JP3008740B2 - Method and apparatus for controlling power supply for electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a power source of an electric discharge machine for supplying machining power between an electrode provided in a machining fluid and a workpiece.

[0002]

2. Description of the Related Art In an electric discharge machine, a workpiece is melted and removed with a discharge energy by supplying a constant current pulse to a machining gap. In order to supply a constant current pulse in the power supply device, the following four types of power supply circuits are conventionally known in general.

That is, as a circuit configuration of the first power supply device,
There is one shown in FIG. The one shown in FIG. 54 is disclosed, for example, in Japanese Patent Publication No. 62-27928 as a "pulse generator used for an electroerosion machine tool". In the figure, 1 is an electrode, 2 is a workpiece, 3 is a control circuit of the switching element 4, 4 is a switching element, 5 is a power supply for supplying a processing current, 6 is a diode for flowing a residual current, and 7 is current detection. Reference numerals 8a and 8b denote stray inductances of wiring, 9 denotes a comparison device, 10 denotes an envelope signal generator, and 18 denotes a servo device that servo-controls the electrode 1.

Next, the operation of this circuit will be described below. Before the discharge is started, the switching element 4 is conductive, and a machining voltage is applied from a power supply 5 to a machining gap between the electrode 1 and the workpiece 2. With the start of electric discharge, a pulse command 16 corresponding to the machining current waveform to be supplied to the machining gap
Are output to the envelope signal generator 10 from a controller not shown in the figure. The pulse command 16 is output by the envelope signal generator 10 as envelope signals 13 and 14. FIG. 55 shows the shapes of the envelope signals 13 and 14. In the comparison device 9, the current flowing in the machining gap is detected by the current detection resistor 7, and the current value of the machining current 15 is detected.
Thus, the envelope signals 13 and 14 are compared with the current machining current value 15, and the control signal 12 to the control circuit 3 is output. The control circuit 3 controls the machining current to be within a certain value by turning on / off the switching element 4 by the control signal 12. That is, the current processing current value 15 is the envelope 1
If it is larger than 3, the switching element 4 is turned off.
F, and when the current machining current value 15 becomes smaller than the envelope 14, the switching element 4 is turned ON to control the machining current.

In the case of this method, the rising speed of the machining current waveform is determined by the magnitude of the current detection resistor 7 and the inductances 8a and 8b of the machining current supply feeder. That is, switching control is performed using the resistance and the inductance as loads.

FIG. 5 shows a circuit configuration of a second power supply device.
8 is shown. The circuit shown in FIG. 58 is disclosed, for example, in Japanese Utility Model Publication No. 57-33949 as a "controlled pulse generating circuit for forming by intermittent electric discharge". The present power supply device can improve the rising and falling speeds of the processing current as compared with the first power supply device and can perform the machining current at a higher speed. In the figure, the auxiliary power supply 28, the first
Switching element 4, current detector 24, reactor 2
2 and the diode 23 constitute a first auxiliary circuit. Also, a power supply 5, an auxiliary power supply 28, a first switching element 4, a current detector 24, a reactor 22, an electrode 1,
The workpiece 2 and the second switching element 20 form a main circuit.

Next, the operation of this circuit will be described below. In the first auxiliary circuit, the switching element 4 is driven by the control circuit 27 based on the detection signal of the current detector 24. The control circuit 27 controls the switching of the switching element 4 so that the current flowing through the current detector 24 becomes constant. In this case, since the reactor 22 is inserted in the circuit, it is possible to keep the current flowing in the first auxiliary circuit more constant.

In the second power supply device, a dedicated second switching element 20 is provided for turning on / off the discharge pulse. Even when the discharge pulse is OFF, a current within a certain range constantly flows through the first auxiliary circuit, and a machining current is supplied from the first auxiliary circuit at the moment when the discharge is started. You. Therefore, the rise of the current can be made very fast.
The current during discharge flows through a main circuit including the power supply 5, the auxiliary power supply 28, the first switching element 4, the current detector 24, the reactor 22, the electrode 1, the workpiece 2, and the second switching element 20. When the discharge ends, the current flowing through the reactor 22 of the main circuit flows through the second diode 23 of the first auxiliary circuit, so that the current in the machining gap can be cut off at high speed.

In the first diode 25, both the first switching element 4 and the second switching element 20 are O
When the FF is formed, a third auxiliary circuit is formed, and the current flowing through the reactor 22 is regenerated to the power supply 5 so that the power supply efficiency is improved. Note that the third auxiliary circuit includes a first diode 25, a current detector 24,
This is a circuit formed by the reactor 22, the second diode 23, and the main power supply 5. FIG. 59 shows a processing current waveform generated by the second power supply device.

FIG. 6 shows a circuit configuration of a third power supply device.
There is one shown as 0. The one shown in FIG. 60 is described, for example, in Japanese Patent Publication No.
32 publication. In the figure, 30a to 3
Reference numeral 0e denotes a drive element for conducting the switching elements 32a to 32e, and constitutes a logic circuit 35. 33a
Reference numerals 30e to 30e denote limiting resistors for controlling the machining current, each having a different value. Electrode 1 and workpiece 2
Between them, a detection device 36 for detecting the start of discharge is provided. The detection device 36 outputs a discharge detection signal 37,
The signal is sent to the logic circuit 35. The logic circuit 35 selects the driving of the switching elements 30a to 30e from the output signal of the oscillator 34 and the discharge detection signal 37.

Next, the operation of this circuit will be described below. The circuit includes a power supply 5 for supplying current. A parallel body in which a series body of switching elements 32a to 32e and current limiting resistors 33a to 33e is connected in parallel is connected to the power supply 5 in series. The resistance values of the current limiting resistors 33a to 33e are configured to be different from each other.
.., 2 times, 4 times,... Now, when it is intended to supply a rectangular wave with a constant current value as shown in FIG. 61, some of the current limiting resistors 33 are selectively turned on and turned on by operating the switching element 32 by the drive circuit 30. . When the discharge starts, a machining current is supplied to the gap through the selected resistor 33. The difference voltage between the output voltage of the main power supply 5 and the discharge voltage generated in the machining gap between the electrode 1 and the workpiece 2 is applied to each current limiting resistor, and the current flowing through the current limiting resistor is determined. . Since the discharge voltage is usually a constant value, the machining current is uniquely determined by selecting the current limiting resistance value.

Further, as shown in FIG. 62, the rising speed of the current waveform can be controlled. Fig. 6
When the switching element 32 has risen to 48, the current can be further increased by successively turning the switching element 32 on and off, and the current can be increased while the gradient is reduced. . Controlling such a discharge current waveform intentionally is usually performed in order to control the machining state more finely.

FIG. 6 shows a circuit configuration of a fourth power supply unit.
3 is shown. The one shown in FIG. 63 is disclosed, for example, in the specification of US Pat. No. 4,306,135. In the figure, 49 is a fixed current limiting resistor, 50 is F
A semiconductor amplifier 51 such as an ET, a discharge pulse ON, an OF
A switching element for turning on and off the semiconductor amplifier 50 to perform the F operation; 52, a digital signal for defining the current waveform shape of the discharge pulse; 53, a D / A converter for converting the digital signal into an analog signal; 55 is a limiting resistor for the amplifier 54.

The operation of this circuit will be described below. A signal is output from the oscillator 21 at the ON / OFF timing of the discharge pulse, and the switching element 51 is driven. After the discharge occurs, the current supplied to the machining gap between the electrode 1 and the workpiece 2 is determined by the resistance values of the fixed resistor 49 and the semiconductor amplifier 50. The semiconductor amplifier 50 can be operated as a variable resistor by using, for example, an FET.

The characteristics of the FET are as shown in FIG. That is, if VGS is arbitrarily determined, ID is kept constant even if VDS fluctuates somewhat. That is, there is a feature that the machining current is always controlled to be constant irrespective of the slight fluctuation of the power supply voltage 5. Therefore, the current during the discharge is stable, and the discharge is interrupted in the middle of the pulse, that is, the so-called pulse crack is unlikely to occur, and extremely stable processing can be realized.

The signal to the gate G of the FET 50 is set to 1
An arbitrary waveform can be obtained by changing within a pulse, and since this also has a constant current characteristic with respect to the command value G, particularly stable machining can be performed.

Since the conventional electric power source for electric discharge machining is configured as described above, there are the following problems.

That is, a "pulse generator used in an electroerosion machine tool" disclosed in Japanese Patent Publication No. 62-27928.
In, in order to essentially control the machining current value within the specified range in the switching control,
The machining current waveform is a waveform having a certain ripple width, as shown in FIG. This ripple width is typically on the order of a few amps. FIG. 56 shows an example of the generated machining current pulse.
FIG. In FIG. 56, the setting of the machining current value is large,
This is a so-called rough machining current setting. In this case, the current waveform 47b has a ripple width with respect to the peak value 13 of the machining current command value (this is approximately the interval between the command values 13 and 14).
Is small, there is no particular problem in processing. However, when the command value of the current peak value becomes small as shown in FIG. 57, not only does the lower limit value 14 of the command value no longer make sense, but also a triangular wave such as 47c originally intended to obtain a rectangular wave. As a result, the pulse cannot be maintained for a certain period of time, and is interrupted. In this case, a desired processing state cannot be obtained.

That is, the current waveform to be controlled by the switching control is not suitable for control of a fine current waveform such as a finishing process due to a ripple of the current waveform, and there is a problem that desired processing cannot be realized. Was.

The "controlled pulse generation circuit for forming by intermittent electric discharge" disclosed in Japanese Utility Model Publication No. 57-33949 solves the problems of the one disclosed in Japanese Patent Publication No. 62-27928 to some extent. I can do it. That is, the reactor 22 in the circuit of FIG.
, The current is easily kept constant, and the ripple width of the current waveform can be considerably reduced as compared with the technique of Reference 1. Normally, when a reactor is inserted, the current can be easily kept constant, but there is a disadvantage that the rising and falling speeds cannot be obtained.
In Reference 2, a peak current value is secured in advance using a first auxiliary circuit, and at the start of a discharge pulse, the discharge circuit is turned on or off using another second switching element 20. By doing so,
The fall speed has been improved. However, this requires the auxiliary power supply 28.

Although the output voltage of the auxiliary power supply 28 may be smaller than that of the power supply 5 which is the main power supply, the output current needs to be substantially the same as the machining current. It is easy to become a big thing. In other words, the point that hinders the construction of the circuit at a low cost,
This is one of the problems of this technology.

Furthermore, in the technique disclosed in Japanese Utility Model Publication No. 57-33949, the discharge pulse waveform is controlled while controlling the rising and falling speeds thereof, as in the technique disclosed in Japanese Patent Publication No. 62-27928. It is almost difficult to obtain such a discharge waveform, and there is a problem that only a square wave as shown in FIG. 23 is obtained.

In the technique disclosed in Japanese Patent Publication No. 2-34732 entitled "Control Method of Power Supply for EDM", Japanese Patent Publication No. 62-27928 and Japanese Utility Model Publication No. 57-339 are disclosed.
For example, the problems disclosed in the Japanese Patent Publication No. 49 can be solved.

In the device disclosed in Japanese Patent Publication No. 2-34732, the machining current value is controlled by a constant voltage power supply and a resistor inserted therein without controlling the electric discharge machining current by switching control. I have. Therefore, the obtained discharge current waveform has almost no current ripple as shown in FIG. 61, and as shown in FIG. 62, by turning on / off the resistors 33a to 33d in the circuit at a high speed as shown in FIG. It is possible to arbitrarily set a rising speed and a current waveform shape.

However, the problem with this technique is that the current is not controlled directly, but is controlled by a resistance value that limits the current. is there. That is, even if a constant current value is set, if the power supply voltage fluctuates, the same machining state cannot be obtained.

Further, it is known that the discharge gap between the electrode 1 and the workpiece 2 is physically a constant voltage load of about 25V. Therefore, most of the difference voltage between the output voltage of the power supply 5 and the voltage drop of 25 V in the discharge gap is applied to the current limiting resistor 33, which is consumed as heat energy. That is, as the power source of the electric discharge machine,
The power supply efficiency is inevitably lower than those disclosed in JP-A-27928 and JP-B-57-33949. This hinders downsizing of the power supply device and makes it difficult to realize the same function at low cost. As described above, in the device of Document 3, it is difficult to keep the machining current constant, the power supply efficiency is poor,
As a result, there has been a problem in increasing the size and cost of the apparatus.

Further, in the specification of US Pat. No. 4,306,135, a part of the problems disclosed in Japanese Patent Publication No. 2-34732 has been solved.

That is, the one disclosed in the specification of US Pat. No. 4,306,135 is different from the one disclosed in Japanese Patent Publication No. 2-34732 in that a plurality of current limiting resistors are installed.
A semiconductor amplifier is used. In the case of this example, since a FET is particularly used as the semiconductor amplifier, a constant current characteristic as shown in FIG. 64 is obtained. In other words, a constant current can be maintained and controlled even when the output voltage of the power supply 5 fluctuates, and the constant current can be controlled even during the duration of the discharge pulse, so that extremely stable machining can be realized.
In the sense that the current in the pulse can be made constant,
More stable processing can be realized than switching power supplies such as those disclosed in JP-A-27928 and JP-B-57-33949. Furthermore, as compared with the one disclosed in Japanese Patent Publication No. 2-37322, since the resistance value at the start of discharge can be extremely small, there is a feature that the rise of the discharge current can be accelerated.

However, the difference voltage between the output voltage of the power supply 5 and the machining gap is all applied to the semiconductor amplifier 50.
That is, the heat energy to be consumed by the semiconductor amplifier 50 is large. Semiconductors are particularly vulnerable to heat as compared with ordinary electric components, and heat dissipation design is important. However, in the technology disclosed in U.S. Pat. No. 4,306,135, heat is particularly large because a semiconductor is used as a variable resistor in an active area in addition to being used as a switching element. . In other words, it is very difficult to design a circuit that can realize rough machining of electric discharge machining that requires a current peak value of tens of amperes or more without allowing a large current to flow.

That is, the technique disclosed in the specification of US Pat. No. 4,306,135 has a problem that a large current suitable for rough machining cannot be controlled.

The present invention has been made in order to solve the above-mentioned problems, and has a small ripple in a processing current pulse, can easily form a small current in finishing processing, and has an extremely high power supply efficiency. Therefore, it is an object of the present invention to obtain a power supply for an electric discharge machine that can be configured to be small and inexpensive.

[0031]

[0032]

According to a first aspect of the present invention, there is provided a power supply device for an electric discharge machine, wherein a power supply for supplying machining energy to a machining gap, a first switching element, and a resistor are connected in series. One processing circuit, current detection means for detecting a current flowing through the first processing circuit, and one or more sets of circuits in which a second switching element and a resistor are connected in series. The first switching element and the resistor of the one processing circuit are connected in parallel to the resistor or a part of the resistor so that the current can be supplied to the processing gap by overlapping with the current from the first processing circuit. A second processing circuit configured, a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to a processing gap, the current command value signal or a partial signal thereof and the current Detection means First signal addition / subtraction means for calculating and outputting a difference from the outputs, and a first signal for outputting a signal to a first switching element of the first processing circuit in accordance with an output of the first signal addition / subtraction means. Control means; second signal addition / subtraction means for calculating and outputting the difference between the current command value signal and the output of the current detection means; and the second processing circuit in response to the output of the second signal addition / subtraction means. Second control means for outputting a signal to one or more second switching elements;
Is provided.

A power supply device for an electric discharge machine according to a second aspect of the present invention includes a power supply for supplying machining energy, a first switching element, and a first machining circuit in which a resistor is connected in series. Current detecting means for detecting a current flowing in the processing circuit of the first and one or a plurality of circuits to which the semiconductor amplifier is connected, the first switching element and the resistance of the first processing circuit or a part of the resistance And a second processing circuit which is connected in parallel with the first processing circuit and is configured to be able to supply current to the processing gap by superimposing the current from the first processing circuit, and to supply the current to the processing gap. Means for setting a current command value signal corresponding to the waveform shape of the current pulse; and a first signal addition / subtraction means for calculating and outputting a difference between the current command value signal or a partial signal thereof and an output from the current detection means. And first control means for outputting a signal to a first switching element of the first processing circuit in accordance with an output of the first signal addition / subtraction means; and a current command value signal and an output of a current detection means. Second to calculate and output the difference of
And a second control means for outputting a signal to the semiconductor amplifier of the second processing circuit in accordance with the output of the second signal addition / subtraction means.

A power supply device for an electric discharge machine according to a third aspect of the present invention includes a power supply for supplying machining energy, a first switching element for intermittently supplying and accumulating electric energy from the power supply, An electric energy storage circuit configured by connecting the reactor and the first diode in series; and an output current from the electric energy storage circuit is connected to be supplied to the machining gap. A third switching element for supplying the output current in a pulse shape, and a third switching element connected to return the residual current generated in the machining gap to the electric energy storage circuit when the third switching element is turned off. A first processing circuit composed of two diodes, a current detection means for detecting a current flowing through the first processing circuit, and a second switch One or a plurality of sets of circuits in which a switching element and a resistor are connected in series are connected in parallel to the electric energy storage circuit of the first processing circuit, and the first processing circuit A second processing circuit configured to be able to supply a current to the machining gap by superimposing the current, and a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to the machining gap. A first signal adding / subtracting means for calculating and outputting a difference between the current command value signal or a part of the signal and an output from the current detecting means; A first control means for outputting a signal to the first switching element of the processing circuit, a second signal addition / subtraction means for calculating and outputting a difference between the current command value signal and the output of the current detection means, Of the signal addition and subtraction means It is obtained by a structure comprising a second control means for outputting a signal to one or more second switching elements of the second processing circuit in response to a force.

A power supply device for an electric discharge machine according to a fourth aspect of the present invention includes a power supply for supplying machining energy, a first switching element for intermittently supplying and accumulating electric energy from the power supply, An electric energy storage circuit configured by connecting a reactor and a first diode in series, and an output current from the electric energy storage circuit being connected to be supplied to the machining gap, And a third switching element for supplying the output current in a pulse form to the electric energy storage circuit, and a residual current generated in the machining gap when the third switching element is turned off. A first processing circuit including a second diode;
One or more sets of a circuit to which a semiconductor amplifier is connected are connected in parallel to an electric energy storage circuit of the first processing circuit, with current detection means for detecting a current flowing through the first processing circuit. A second processing circuit configured to be able to supply a current to the processing gap by superimposing the current from the first processing circuit, and a waveform shape of a current pulse to be supplied to the processing gap. Means for setting a corresponding current command value signal; first signal addition / subtraction means for calculating and outputting a difference between the current command value signal or a part thereof and an output from the current detection means; First control means for outputting a signal to the first switching element according to the output of the addition / subtraction means, second signal addition / subtraction means for calculating and outputting the difference between the current command value signal and the output of the current detection means, This second Second outputting a signal to the semiconductor amplifier of the second processing circuit in accordance with the output of the signal subtraction means
And a control means.

A power supply device for an electric discharge machine according to a fifth aspect of the present invention includes a first current source for supplying a current pulse to a machining gap, and a current supplied to the machining gap by the first current source. A current detecting means for detecting, and the first current being connected in parallel to the first current source and configured to supply a current to a machining gap by superimposing the current from the first current source. A second current source having a response speed of an output current higher than that of the current source; a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to the machining gap; Subtraction means for reducing
A first control unit that outputs an output of the subtraction unit as a current command value to the first current source; and a difference between the current command value signal and an output from the current detection unit. And a second control means for outputting the current command as a current command.

A power supply device for an electric discharge machine according to a sixth aspect of the present invention includes a first current source for supplying a current pulse to the machining gap, and a current supplied to the machining gap by the first current source. A current detecting means for detecting, and the first current being connected in parallel to the first current source and configured to supply a current to a machining gap by superimposing the current from the first current source. A second current source having a higher response speed of the output current than the source, a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to the machining gap, and a value of 1 or less for the current command value signal Multiplying means for multiplying by a value exceeding 0; first control means for outputting an output of the multiplying means as a current command value to the first current source; The difference between the output and the current command of the second current source A second control means for outputting Te is obtained by the comprising the structure.

A power supply device for an electric discharge machine according to a seventh aspect of the present invention includes a first current source for supplying a current pulse to the machining gap, and a current supplied to the machining gap by the first current source. A current detecting means for detecting, and the first current being connected in parallel to the first current source and configured to supply a current to a machining gap by superimposing the current from the first current source. A second current source whose output current response speed is faster than that of the first current source, and a second current source connected in parallel to the first current source and supplying a current in a direction opposite to a current supply direction of the second current source. A third current source having a higher response speed of the output current than the first current source; a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to a machining gap; The command value signal is a current command value to the first current source. First control means for outputting to the first current source, and a positive difference detected by the current command value signal and current detection means of the first current source is output as a current command for the second current source. A second control unit, and a third control unit that outputs a negative difference detected by the current detector of the first current source and the current command value signal as a current command of a third current source. It is configured to be provided.

According to an eighth aspect of the present invention, there is provided a method for controlling a power supply for an electric discharge machine, comprising: a constant current supply unit having at least a first switching element; and an output current interrupting section having a second switching element. In a method for controlling a power supply for an electric discharge machine that supplies machining power between an electrode provided therein and a workpiece, an output current level and an output current ripple of the constant current supply unit are set, and The sum of the output current level and the output current ripple is used as the output current command signal of the constant current supply unit, and the output current command signal is compared with the output current of the constant current supply unit. This controls the switching element of the constant current supply unit.

A power supply device for an electric discharge machine according to a ninth aspect of the present invention comprises a detecting means for detecting an output current of the constant current supply unit;
Output current level setting means for commanding the output current level of the constant current supply unit, ripple current setting means for commanding the output current ripple of the constant current supply unit, and the ripple current setting means for setting the output current level setting means Comparing means for comparing the set value obtained by adding the set value of the above with the detected value of the detecting means;
And means for controlling the switching element to be turned on and off.

According to a tenth aspect of the present invention, in the power supply device for an electric discharge machine according to the ninth aspect , the ripple current setting means sets the ripple current set value in accordance with a set value of the output current level setting means. It has a modulating means for modulating a signal frequency.

Further, a power supply device for an electric discharge machine according to an eleventh aspect of the present invention includes a detecting means for detecting an output current of the constant current supply unit, an output current level setting means for commanding an output current of the constant current supply unit, A ripple current setting means for instructing a ripple current of an output current of the current supply unit; a means for outputting a synchronization signal synchronized with a setting signal of a ripple current setting value of the ripple current setting means; and setting of the output current level setting means Comparison means for comparing a set value obtained by adding a set value of the ripple current setting means to a value and a detection value of the detection means,
Receiving the output of the comparing means and the synchronization signal,
And gate means for removing noise caused by the opening and closing of the switching element, and means for controlling on / off of the first switching element according to the output of the gate means.

A power supply device for an electric discharge machine according to a twelfth aspect of the present invention provides a first constant current supply section, a second constant current supply section, and a first constant current supply section for detecting an output current of the first constant current supply section. (1) detecting means, second detecting means for detecting the output current of the second constant current supply unit, output current level setting means for instructing the output current levels of the first and second constant current supply units, First ripple current setting means for instructing an output current ripple of the first constant current supply unit, and a second ripple current for instructing a setting value 180 degrees out of phase with the setting value of the first ripple current setting means Setting means for comparing a set value obtained by adding a set value of the first ripple current setting means to a set value of the first and second output current level setting means with a detected value of the first detecting means; And a first and second output current level setting means. Second comparison means for setting value obtained by adding the set value of the on setting the second ripple current setting means and comparing the detected value of said second detecting means, the first,
And means for controlling on / off of the first switching element of the first and second constant current supply units in accordance with the comparison of the second comparing means.

A power supply unit for an electric discharge machine according to a thirteenth aspect of the present invention includes a detecting means for detecting an output current of the constant current supply unit, an output current level setting means for commanding an output current level of the constant current supply unit, A comparing means for comparing a set value of the output current level setting means with a detection value of the detecting means, and outputting a signal for turning off a first switching element of the constant current supply section based on the comparison result; After inputting the comparison output, the comparing means outputs a signal for turning off the first switching element of the constant current supply unit, and then outputs a signal for turning on the first switching element of the constant current supply unit after a lapse of a predetermined time. It is configured to include timer means, and means for controlling on / off of the first switching element based on the output of the timer means.

According to a fourteenth aspect of the present invention, there is provided a method for controlling a power supply for an electric discharge machine, comprising: a first direct current power supply, a first switching element, a constant current supply section comprising a diode and a reactor, and In a control method of a power supply for an electric discharge machine for supplying machining power between an electrode provided and a workpiece, a current corresponding to a current command value signal is obtained by switching the first switching element at an arbitrary cycle. While supplying to the machining gap from the first DC power supply,
A current component for suppressing a decrease in the output current generated when the first switching element is turned off during the supply of the current is supplemented.

A power supply device for an electric discharge machine according to a fifteenth aspect of the present invention comprises: a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than a discharge voltage to a machining gap;
A third switching element and a series body of the diode,
It is connected in parallel to the diode of the constant current supply unit.

A power supply device for an electric discharge machine according to a sixteenth aspect of the present invention is the power supply device for an electric discharge machine according to the fifteenth aspect , wherein the first comparison means compares the current command value with the detected current value of the reactor. Second comparing means for comparing the overcurrent command value with the detected current value of the reactor; timer means having an input terminal connected to the output of the first comparing means; First state storage means connected to the output of the means and having a set input terminal connected to the inverted signal of the output of the first comparison means, wherein the output of the timer means and the output of the first state storage means are provided. Controlling the first switching element by the product of
The third switching element is controlled by the product of the output of the first state storage means and the discharge signal, and the second switching element is controlled by the discharge signal, and the current detection value of the reactor exceeds the current command value. When the first switching element is turned off for the time set in the timer means,
When the detected current value of the reactor exceeds the overcurrent command value, the third switching element is also turned off.

A control method of a power supply for an electric discharge machine according to a seventeenth aspect of the present invention includes a constant current supply unit comprising a first DC power supply, a first switching element, a diode and a reactor, In a control method of a power supply for an electric discharge machine for supplying machining power between an electrode provided and a workpiece, when the output current is controlled at a constant current level, the third DC power supply may be higher than a discharge voltage and may be higher than the discharge voltage. A voltage lower than the voltage supplied from the DC power supply is supplied to the machining gap, and at this time, the first switching element is turned off, and a switching element separate from the first switching element is provided. By switching at an arbitrary cycle, the current from the third DC power supply is controlled.

A power supply device for an electric discharge machine according to an eighteenth aspect of the present invention includes: a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap;
A third switching element and a series body of the diode,
A third DC power supply connected in parallel to the diode of the constant current supply unit and having a voltage capable of supplying a voltage higher than the discharge voltage to the machining gap and lower than the voltage supplied from the first DC power supply; 4 switching elements;
A series body with a diode is connected in parallel to the diode of the constant current supply unit.

A power supply device for an electric discharge machine according to a nineteenth aspect of the present invention is the power supply device for an electric discharge machine according to the eighteenth aspect , wherein the first comparing means compares the current command value and the detected current value of the reactor. Second comparing means for comparing the overcurrent command value with the detected current value of the reactor; timer means having an input terminal connected to the output of the first comparing means; First state storage means connected to the output of the means and having a set input terminal connected to the inverted signal of the output of the first comparison means, the sum of the output of the timer means and the current increase signal; Controlling the fourth switching element by the product of the output of the first state storage means and the discharge signal, and controlling the first switching element by the product of the output of the timer means, the current increase signal and the discharge signal; and The third switching element is controlled by the product of the output of the first state storage means and the discharge signal, the second switching element is controlled by the discharge signal, and the detected current value of the reactor exceeds the current command value. In this case, the fourth switching element is turned off for a time set in the timer means, and when the current detection value of the reactor exceeds the overcurrent command value, the third and fourth switching elements are also turned off. .

A power supply device for an electric discharge machine according to a twentieth aspect of the present invention comprises: a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than a discharge voltage to a machining gap;
A third switching element and a series body of the diode,
A fourth DC power supply that can be connected in parallel to the diode of the constant current supply unit and can change the voltage, a fifth switching element, and a series body of the diode are connected to the diode of the constant current supply unit. Are connected in parallel.

[0052] The power supply device for an electrical discharge machine according to the invention of the twenty-first, in the power supply device for an electrical discharge machine according to the twentieth invention, a first comparison means for comparing the current detection value of the current command value and a reactor Second comparing means for comparing the overcurrent command value with the detected current value of the reactor; timer means having an input terminal connected to the output of the first comparing means; First state storage means connected to the output of the means and having a set input terminal connected to the inverted signal of the output of the first comparison means, wherein the output of the timer means and the output of the first state storage means are provided. And the fifth switching element is controlled by the product of
The first switching element is controlled by the product of the no-load voltage signal and the discharge signal, and the third switching element is controlled by the product of the output of the first state storage means and the discharge signal. The second switching element is controlled, and when the current detection value of the reactor exceeds the current command value, the fifth switching element is turned off for the time set in the timer means, and the current detection value of the reactor is changed to the overcurrent command value. When the value is exceeded, the third and fifth switching elements are also turned off.

A power supply device for an electric discharge machine according to a twenty-second aspect of the present invention includes: a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap;
A third switching element and a series body of the diode,
A fifth DC power supply connected in parallel to the diode of the constant current supply unit and having a voltage capable of supplying a voltage higher than a voltage supplied from the first DC power supply to a machining gap; and a sixth switching element. And a series body of a resistor and a resistor are connected in parallel to the machining gap.

[0054] The power supply device for an electrical discharge machine according to the invention of a 23, the power supply device for an electrical discharge machine according to the invention of a 22, a first comparator means for comparing the current detection value of the current command value and a reactor Second comparing means for comparing the overcurrent command value with the detected current value of the reactor; timer means having an input terminal connected to the output of the first comparing means; First state storage means connected to the output of the means and having a set input terminal connected to the inverted signal of the output of the first comparison means, wherein the output of the timer means and the output of the first state storage means are provided. Controlling the first switching element by the product of
The third switching element is controlled by the product of the output of the first state storage means and the discharge signal, the second switching element is controlled by the discharge signal, and the detected current value of the reactor exceeds the current command value. In this case, the first switching element is turned off for the time set in the timer means, and when the current detection value of the reactor exceeds the overcurrent command value, the third switching element is also turned off. The sixth switching element is turned on by a product of the signal and the signal.

In the power supply device for an electric discharge machine according to a twenty- fourth aspect, the first DC power supply is constituted by connecting a plurality of DC power supplies having a predetermined voltage in series, and the first DC power supply is connected to the plurality of DC power supplies. One of them is a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap, and a series body of a third switching element and a diode is provided at one end thereof. Is connected to a connection point between the second DC power supply and another DC power supply, and the other end is connected to a connection point between the first switching element and the reactor.

A power supply device for an electric discharge machine according to a twenty-fifth aspect of the present invention is the power supply device for an electric discharge machine according to the twenty- fourth aspect, wherein the other of the plurality of DC power supplies is discharged to a machining gap. A sixth DC power supply having a voltage higher than the voltage and lower than the voltage supplied from the first DC power supply having a voltage that can be supplied together with the second DC power supply, and one end of a series body of a fourth switching element and a diode; With the sixth
And a connection point between a DC power supply other than the second DC power supply and a DC power supply other than the second DC power supply, and the other end is connected to a connection point between the first switching element and the reactor.

[0057] The power supply device for an electrical discharge machine according to the invention of a 26 is the power supply device for an electrical discharge machine according to the invention of a 24 or 25, serially connected DC power eighth to the first DC power supply In addition, one end of a series body of a sixth switching element and a resistor is connected to one end of the eighth DC power supply, and the other end is connected to an electrode or a workpiece.

[0058]

[0059]

The second processing circuit according to the first to fourth inventions comprises a current corresponding to the difference between the current command value signal and the current generated by the first processing circuit, that is, a ripple generated by switching of the first processing circuit. The current to fill the current is superimposed on the current from the first machining circuit and supplied to the machining gap to reduce the ripple of the discharge current pulse.

The first DC source according to the fifth and sixth aspects of the present invention supplies a current based on a signal obtained by subtracting a predetermined amount from the current command value signal to the machining gap, and the second DC source supplies a current command. A current corresponding to the difference between the value signal and the current from the first DC source is supplied to the machining gap in a manner superimposed on the current from the first DC source, and the ripple of the discharge current pulse is reduced.

The first DC source according to the seventh invention supplies a current based on a current command value signal to the machining gap, and the second current source supplies a current value and a current from the first DC source. A current corresponding to a positive difference from the command value signal is supplied to the machining gap so as to be superimposed on the current from the first DC source, and the third current source further comprises a current value from the first DC source. A current corresponding to the negative difference between the current and the current command value signal is supplied to the machining gap in a manner superimposed on the current from the first DC source to reduce the ripple of the discharge current pulse.

According to the eighth and ninth aspects, the output current level and the output current ripple of the constant current supply unit are set, and the set output current level and the output current ripple are added. Is used as the output current command signal of the constant current supply unit, and the output current command signal is compared with the output current of the constant current supply unit, and the switching element of the constant current supply unit is controlled based on the comparison result to discharge Reduce the ripple of the current pulse.

According to the tenth aspect, the ripple current setting means having the modulation means for modulating the setting signal frequency of the ripple current setting value in accordance with the setting value of the output current level setting means, wherein the setting of the output current level setting means is performed. When the level is high, the setting signal frequency of the ripple current setting value is lowered, and when the setting level of the output current level setting means is low, the setting signal frequency of the ripple current setting value is increased to reduce the ripple of the discharge current pulse. .

According to the eleventh aspect , the output current level and the output current ripple of the constant current supply unit are set, and the sum of the set output current level and the output current ripple is added to the constant current. The output current command signal of the supply unit, and the output current command signal is compared with the output current of the constant current supply unit, and based on the comparison result, the switching element of the constant current supply unit is controlled, and Reduces ripple. Further, the gate means removes noise accompanying opening and closing of the first switching element of the constant current supply unit.

According to the twelfth aspect , the output current level of the constant current supply unit, the first output current ripple, and the second output current which is 180 degrees out of phase with respect to the first output current ripple. A ripple is set, and the sum of the set output current level and the first output current ripple is used as a first output current command signal of a first constant current supply unit. The sum of the level and the second output current ripple is used as the second output current command signal of the second constant current supply unit, and the first output current command signal and the output of the first constant current supply unit are output. And comparing the second output current command signal with the output current of the second constant current supply unit, based on the comparison result, and controlling the switching element of the first constant current supply unit. Do this Comparison result the switching element of the second constant current supply section is controlled on the basis of, reducing the ripple of the discharge current pulse.

According to the thirteenth aspect , the output current level and the output current ripple of the constant current supply section are set, and the sum of the set output current level and the output current ripple is added to the constant current. The output current command signal of the supply unit is compared with the output current command signal and the output current of the constant current supply unit. Based on the comparison result, a signal for turning off the first switching element of the constant current supply unit is output. The timer means outputs a signal for turning on the first switching element of the constant current supply unit after a predetermined time has elapsed after the comparison means outputs a signal for turning off the first switching element of the constant current supply unit. Thus, the ripple of the discharge current pulse is reduced.

According to a fourteenth aspect of the present invention, a current for suppressing a decrease in output current generated when the first switching element is turned off during current supply is supplemented to prevent the current from dropping sharply. Reduce pulse ripple.

According to a fifteenth aspect , the series body of the second DC power supply, the third switching element, and the diode having a voltage equal to or slightly lower than the discharge voltage is provided when the current is supplied to the first switching element. The amount of current that suppresses the decrease in output current that occurs when the device is turned off is supplemented to prevent the current from dropping abruptly, thereby reducing the ripple of the discharge current pulse.

According to the sixteenth aspect , in addition to the function of the fifteenth aspect , even if an overcurrent flows due to a short circuit between the electrode and the workpiece, the current command value and the The output current increases and decreases between the output current value and the overcurrent command value, thereby preventing the short-circuit current from increasing.

According to the seventeenth aspect , when the output current is controlled at a constant current level, the current is prevented from suddenly increasing and the ripple of the discharge current pulse is reduced.

A third DC power supply having a voltage higher than the discharge voltage and lower than the voltage supplied from the first DC power supply to the machining gap according to the eighteenth aspect , and a fourth switching element. When the output current is controlled at a constant current level, the series body with the diode prevents the current from rising sharply and reduces the ripple of the discharge current pulse.

Further, according to the nineteenth aspect, when a high current rise is required immediately after discharge or the like, the output current is controlled by the first switching element and the fourth switching element so that the output current becomes a constant value. After that, the output current is controlled by the fourth switching element, so that current control with little ripple is performed.

Further, according to the twentieth aspect , the series body of the fourth DC power supply, the fifth switching element, and the diode having a voltage corresponding to the gradient of the rise of the current can reduce the ripple when increasing the output current, and can reduce the ripple. Of the current rise.

The twenty-first aspect of the invention operates to eliminate current ripple from the occurrence of discharge until the current reaches the command value.

According to a twenty-second aspect of the present invention, the fifth DC power supply having a voltage capable of supplying a voltage higher than the voltage supplied from the first DC power supply to the machining gap and the sixth switching element are connected in series. In addition, it functions to reduce the ripple of the discharge current pulse and reliably generate the discharge.

According to the twenty- third aspect, when the generation of the discharge is delayed, the sixth switching element is turned on by the high-voltage pulse signal so as to reliably generate the discharge.

According to the twenty-fourth, twenty-fifth, and twenty-sixth aspects of the present invention, the ripples of the discharge current pulse are reduced, and each of the first and fourth DC power supplies has a low voltage. Can be used, and the power supply can be used effectively.

[0078]

[Embodiment 1] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. This embodiment mainly describes the first invention. FIG. 1 is a circuit diagram of a power supply of an electric discharge machine according to a first embodiment of the present invention. In FIG.
1 is an electrode, 2 is a workpiece, 4 is a first switching element, 5 is a power supply, 6 is a diode for flowing a residual current, 7 is a current detector, 100a to 100c are second switching elements, and 101a to 101c are A current limiting resistor having a resistance ratio of 1: 2: 4, which is a factor of 2, 102 denotes a peak value, a duration, a pause, a shape, etc. of a current waveform to a current command value signal generator 103. The current command value signal setting device 103 sets by detecting the start of discharge,
A current command value signal generator 104 for generating a current command value signal set by the current command value signal setting device 102 is the output signal.

A signal converter 105 adds or subtracts a fixed amount to or multiplies the output signal 104 by a fixed ratio.
6, a first signal adder / subtracter for calculating a difference between the output signal 106 and the current value of the detection signal 112 detected by the current detector 7; 108, an output signal;
109 is a logic circuit that outputs a logic signal for turning on and off the first switching element 4 based on the output signal 108, 110 is its output signal, and 111 is the output signal 1
An amplifier 10 drives the first switching element 4.

Reference numeral 112 denotes a detection signal representing the current value of the current obtained from the current detector 7, and 113 denotes a command value by the current command value signal generator 103 and a detection signal 1 by the current detector 7.
A second signal adder / subtracter for calculating a difference from the current value of twelve;
114 is an A / D converter that digitizes the output of the second signal adder / subtractor 113; 115a to 115c are amplifiers that amplify each bit of the digital signal of the A / D converter 114 and drive the switching elements 100a to 100c; 116 is a machining gap voltage signal for detecting the start of electric discharge, and 117 is a resistor.

In this embodiment, the power supply 5 and the first
The first processing circuit is constituted by connecting the switching element 4, the current detector 7, the resistor 117 and the processing gap in series. Also, current limiting resistors 101a-1
01c and the second series of switching elements 100a to 100c constitute a second processing circuit. The second processing circuit overlaps a current from the first processing circuit with a processing gap. Are connected in parallel to the first processing circuit so that current can be supplied to the first processing circuit. Further, a first control circuit is constituted by the logic circuit 109 and the amplifier 111, and a second control circuit is constituted by the A / D converter 114 and the amplifiers 115a to 115c.

Next, the operation of this circuit will be described with reference to FIGS. First, at the start of machining, an operator who operates the electric discharge machine sets in advance the shape of the current waveform, the continuation time, the pause time, and the like for the current command value signal generation device 103 from the setting device 102. These may be given by a program from an NC control device or the like. The current command value signal generator 103 generates a signal required as a power supply device in actual machining, such as timing for applying a voltage to the machining gap, based on the conditions of the setting device 102. In other words, after the voltage is applied to the machining gap, if the discharge is started, the machining current waveform is output for a certain period of time. A current command value signal that defines an operation such as application is generated.

The signal 104 output from the current command value signal generator 103 is also common in the power supply of a conventional electric discharge machine. This output signal 104 is converted into an output signal 106 by a signal converter 105. The output signal 106 is converted so that it is equal to or slightly lower in signal level than the output signal 104. The difference between the output signal 106 and the signal 112 (the current flowing in the first processing circuit) detected from the current detector 7 is calculated by the first signal adder 107 and the output signal 1
08.

The output signal 108 is further applied to the logic circuit 10
It is sent to 9. The logic circuit 109 outputs the output signal 108
To output the operation timing of the first switching element 4 based on the first switching element 4 when the current value detected by the current detector 7 is smaller than the command value given by the signal 106. 4 to turn on the first switching element 4 when the current value detected by the current detector 7 is larger than the command value given by the signal 106. , Output signals 110 respectively. The amplifier 111 outputs the first switching element 4 based on the output signal 110 thereof.
Drive.

FIG. 2A shows the above description in the form of operating current waveforms. The shape surrounded by 104a to 104c corresponds to the output signal 104 in FIG. 1 and is a current waveform command value. Now, assuming that the signal converter 105 does not particularly perform signal conversion, the output signal 106 also becomes the output signal 10.
4 is obtained. When the discharge is started with the first switching element 4 turned on and the discharge current starts to flow, the current supplied from the first switching element 4 starts to rise as indicated by 121 in FIG.

The logic circuit 109 has a preset threshold value. When the difference signal 108 becomes “0”, the output shifts from “1” to “0” and the first switching element 4 OFF [Timing 119 in FIG. 2 (a)]
When the difference signal 108 becomes the lower threshold value 118b, the output shifts from "0" to "1" and the first switching element 4 is turned ON (timing 120 in FIG. 2A). Is output. That is, the first switching element 4
Causes the current to flow between 118a and 118b in FIG. The difference between the so-called 118a and 118b corresponds to the threshold value. At the end of the pulse duration, the current decreases toward zero as indicated by 122. As described above, the current waveform supplied by the first switching element 4 is represented by reference numerals 121, 119 and 12 in FIG.
A jagged waveform indicated by 0, 122, etc. is obtained. That is, this is the current ripple.

In the present embodiment, in order to approach the original output signal 104, that is, the current waveform command value, by compensating for the current ripple, in the present embodiment, the first processing circuit of the first switching element 4 and the like is used. In addition, a second processing circuit composed of a series body of the second switching elements 100a to 100c and the resistors 101a to 101c is provided in parallel with the first processing circuit.

The output signal 104, which is the current command value, and the detection signal 11, which is the current current value, due to the current ripple or the rise delay of the current from the first switching element 4.
2 is detected by the second adder / subtractor 113, and A
/ D converter 114. That is, the difference is digitally converted by the A / D converter 114. In this embodiment, the resistors 101a to 101c are configured so that the ratio is 1: 2: 4. Therefore, each of the resistors 101a to 101c
Are 4: 2: 1, respectively. As described above, since the resistance values of the resistors 101a to 101c are a factor of 2, the three outputs of the A / D converter 114, that is, the logic signals of the logic signals sent to the second switching elements 100a to 100c are output. Eight different current values can be set by combination. By switching this, the current corresponding to the difference between the current command value and the current current value is set to a value corresponding to each of the resistors 101a to 101a.
00c.

FIG. 4 shows the operation timings. FIG. 4A shows the voltage waveform of the machining gap.
(B) is a current waveform of the machining gap, which is indicated by a hatched portion 29
Is a portion supplied with current from the second processing circuit and compensated. FIG. 4C shows the operation timing of the first switching element 4, and FIG.
Operation timings 0a to 100c are shown. FIG. 4E shows an ON / OFF table of the second switching elements 100a to 100c which are turned ON / OFF by signals output from the logic circuits 115a to 115c. In this table, "1" indicates that the switching element is ON. ,
“0” indicates that it is off. First, in a state where a voltage is applied to the machining gap before the start of electric discharge, the first switching element 4 and the second switching elements 100a to 100a.
100c are both ON.

When the start of the discharge is detected at 124 shown in FIG. 4A, the current waveform starts rising as shown in FIG. 4B. At the same time, resistor 10
Since the currents dependent on 1a to 101c decrease, the second switching elements 100a to 100c
As shown in (e), the resistor 101a is switched as appropriate (so that the current component corresponding to the difference between the current command value and the current current value due to the rise delay of the current from the first switching element 4 is compensated). The current supply from to 101c is reduced. When the current value has almost reached the command value, the current from the first switching element 4 becomes higher
8a, the first switching element 4 becomes OF
F (timing 131 in FIG. 4C). Then the first
From the switching element 4 of the lower threshold 118
Begins to drop towards b.

The ripple generated here is detected by the second adder / subtractor 113 in FIG. 1, and the second switching elements 100a to 100c are selectively turned on through the A / D converter 114, and the resistors 101a to 101c A current is supplied that more compensates for the current ripple. FIG. 4D shows an example in which the ripple is filled by turning ON / OFF only the switching element 100a. However, when the ripple is further increased, it goes without saying that another resistor is also selected. . Alternatively, a second switching element and a resistor capable of providing a smaller current compensation, that is, 101a to
If a resistor having a resistance value ratio corresponding to 0.5 with respect to 101c is provided, the current is compensated by a plurality of switching elements, and the ripple is further reduced.

Now, current waveforms when the current set value is small are shown in FIGS. 2 (b) to 2 (d). In FIG. 2B, although the current set value is small, the operation is the same as when the large current value as shown in FIG. 2A is used. FIG. 2C shows a case where the current set value is further reduced and becomes equal to or less than the switching threshold width. Switching threshold is 13
2a and 132b, especially 13
In the lower threshold value of 2b, if it is set to be a value that is different from the current peak value by a certain value, the value may become “0” or less. In this case, control can be performed by changing the lower threshold value, which is originally 132b, to 132c.
At this time, since the threshold width is small, the switching frequency of the first switching element 4 is as shown in FIG.
It is higher than (b).

As the switching frequency increases, the loss due to switching increases in the case of a semiconductor amplifier. For this reason, a more reliable circuit operation can be obtained by setting as shown in FIG. 2D than by raising the switching frequency by inadvertently reducing the threshold width. That is, in a small current setting equal to or smaller than the switching threshold width, the first switching element 4 is always turned off, and the second switching elements 100a to 100c and the resistors 101a to 101 are set.
This is a method in which current is supplied only from the second processing circuit consisting of a series body with c. At this time, since the current set value is small, a decrease in power supply efficiency due to not using power supply switching control does not cause a serious problem.

There is another problem regarding the setting of the switching threshold. FIG. 3 shows a case where the upper switching threshold value 133b is set smaller than the set current peak value 133a. So far, it has been described that the two are set at the same position. That is, FIG.
The coefficient of the signal converter 105 is "1", and no conversion is performed.

When the upper threshold value of the switching is made to coincide with the peak value of the current command value, the switching is actually performed after the upper threshold value is exceeded. Occurs. That is, the switching current flows more than the upper threshold. The shortage of the current command value and the switching current is determined by the second switching elements 100a to 100c and the resistor 101a.
It is compensated and supplied from the second processing circuit composed of a series body with -101c, but the excess cannot be compensated. For this reason, there is a method in which the overshoot of the current value due to the switching delay is calculated in advance, and the upper threshold is somewhat lower than the peak value of the current command value. FIG.
, The current value at 134a is
3b. However, since the upper threshold value 133b is set somewhat smaller than the peak value 133a of the current command, the entire current value does not exceed the current command value.

Although the above description has been made by treating a rectangular wave as the current command waveform, the current waveform used in electric discharge machining is not limited to a rectangular wave. Using a kind of triangular wave current waveform having an arbitrary rising speed as shown in FIG.
It is known that electrode wear can be kept very small. The present invention and the present embodiment can easily create a current waveform having such an arbitrary shape. Of course, since the power supply efficiency is high, it is easy to reduce the size and cost of the power supply, and it is possible to obtain an accurate actual waveform for a desired waveform. In FIG. 5, the switching threshold 135a,
135b is set according to a desired waveform shape 135a. That is, the upper threshold 135a is matched with the waveform shape, and the lower threshold 135b is set as the upper threshold 135a.
Is set to a smaller value by a certain amount. This makes it possible to easily obtain a waveform shape other than a rectangular wave.

As described above, the power supply device of the electric discharge machine according to the first embodiment uses the switching type power supply having high power supply efficiency, so that the power supply can be easily reduced in size and cost. Further, since a resistance type circuit for compensating for the current ripple of the switching power supply is added, there is no current ripple and stable processing can be realized even with a small current.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment mainly describes the second invention. This embodiment is different from the first embodiment in that the second switching elements 100a to 100a used for current compensation are used.
c and a plurality of series circuits of resistors 101a to 101c are connected to one FET 136 and a resistor 137.
And a second processing circuit composed of a series body of FET 136 is a fourth conventional example shown in FIGS.
As described above, by changing the control method, it can be made to function as a variable resistor itself. Therefore, in the first embodiment, the second switching element 10
In the first embodiment, the three second switching elements 1a to 100c are used for the purpose of switching only, and are controlled by analog control.
00a to 100c, three resistors 101a to 101c
Can be replaced with one FET 136 and one limiting resistor 137 as shown in FIG. The other configuration is the same as that of the first embodiment.

Since the FET 136 is driven by an analog voltage signal, the A / D converter 1 required in the first embodiment is required.
14 is unnecessary. After the output signal of the second subtractor 113 is amplified by the amplifier 139, the gate of the FET 136 can be directly driven. That is, the number of components can be reduced, and at the same time, the current can be compensated while keeping the analog signal.
That is, insufficient current compensation due to a so-called quantization error as shown in FIG. 4 of the first embodiment does not occur. The shortage current can be compensated to the last.

Further, the constant current characteristic of the FET 136 can be made constant current not only in the switching control section (first processing circuit) by the first switching element 4 but also in the compensation circuit (second processing circuit). Therefore, it is possible to make the current supplied to the machining gap constant. For this reason, processing becomes stable, and very good processing characteristics can be obtained.

The constant current characteristic of the FET 136 is as follows.
As compared with the method using the resistor in the case of the first embodiment, it is also possible to increase the current response speed, and it is possible to configure a machining power supply device which is excellent in both the accuracy with respect to the command value of the waveform and the ripple.

Even when the FET 136 is used, the problems with respect to the drive timing of the switching element 4 and the upper and lower thresholds for the same are the same as in the first embodiment.

As described above, the power supply device of the electric discharge machine according to the second embodiment uses the switching type power supply having high power supply efficiency, so that the power supply can be easily reduced in size and cost. Further, since a semiconductor amplifier circuit for compensating for the current ripple of the switching power supply is added, a stable current can be supplied even with a small current without a current ripple with a small number of components. Also, the current rise speed is very fast. Even in the processing of any current value for this, it can realize stable machining.

Embodiment 3 FIG. Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment mainly describes the third invention. In this embodiment, a power supply 5 for supplying machining energy, an auxiliary power supply 28, a first switching element 4 for intermittently supplying and storing electric energy from the power supply 5, a current detector 7, a reactor 22, and An electric energy storage circuit configured by connecting the first diode 23 in series, and an output current from the electric energy storage circuit are connected so as to be supplied to the machining gap. A third switching element 20 for supplying an output current in a pulse shape;
A second processing circuit is constituted by the second diode 6 connected to return the residual current generated in the processing gap to the electric energy storage circuit when the switching element 20 is turned off.

Further, similarly to the first embodiment, the current limiting resistors 101a to 101c and the second switching element 10
A plurality of series members 0a to 100c constitute a second processing circuit, and the second processing circuit can supply a current to the processing gap by superimposing the current from the first processing circuit. , And the first processing circuit. Regardless of whether or not a current is flowing in the machining gap, a current is constantly flowing in the electric energy storage circuit, and the current is turned ON and OFF by the third switching element 20. The current O
The time related to N and OFF, that is, the rise time and fall time of the current in the machining gap are reduced. The rising and falling speeds can be higher than those of the switching power supply not using the reactor 22 shown in the first and second embodiments, and the processing can be made more stable.

In FIG. 7, reference numeral 29 denotes a capacitor;
141 is an amplifier for detecting the current value of the current flowing through the reactor 22 based on the output of the detector 7. Reference numeral 142 denotes a third adder / subtracter for calculating a difference between the current value of the electric energy storage circuit and the current command value 104, and 143 turns on / off the third switching element 20 according to the sign of the output signal 104. Logic circuit that outputs a timing signal for The other configuration is the same as that of the first embodiment, and the description is omitted. Further, in FIG.
Although the switching elements 4, 20, and 100a to 100c are represented by using switch symbols, they are not different from the switching elements shown before FIG. 6 and describe the switching elements more generally. .

FIG. 8 shows the timing relationship between the third switching element 20 and the current waveform when a rectangular wave is formed using this embodiment. In the case of this embodiment, the upper and lower thresholds 145a and 145b for switching are set even during the idle time,
6 is set within a certain width. This has the advantage that, when the next pulse rises after the pause time, the current waveform can rise very quickly to the command value.

FIG. 9 is a timing chart when an attempt is made to form, for example, a kind of triangular wave as shown in FIG. In this waveform, the return current 146 exceeds the current command value at the initial rise 147 of the current waveform in order to intentionally set the rise of the current later.
For this reason, at the initial stage, the switching element is turned OFF as indicated by 144 so as not to supply current from the return circuit to the machining gap. A desired waveform can be obtained by supplying a necessary current at the beginning of the current waveform from the resistance circuit side. This could not be realized by the conventional switching circuit and freewheeling circuit alone.

As described above, the power supply device of the electric discharge machine according to the third embodiment uses the switching type power supply and has the circuit for returning the excess current to the power supply. Very high efficiency, miniaturization of power supply,
Cost reduction can be easily realized. In addition, since a resistance type circuit for compensating for the current ripple of the switching power supply is added, there is no current ripple, and it works to realize stable machining even with a small current. Further, the addition of the recirculation circuit allows the width of the machining current pulse to be accurately controlled, thereby realizing stable and highly reproducible machining.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described below with reference to FIGS. This embodiment mainly describes the fourth invention. In FIG. 10, a power supply 5 for supplying processing energy, a first switching element 4 for intermittently supplying and storing electric energy from the power supply 5, a current detector 7, a reactor 22, and a third switching element 20 and the first diode 23 are connected in series, and the electric energy storage circuit is configured to store the residual current generated in the machining gap when the third switching element 20 is turned off. A second processing circuit is composed of the second diode 6 connected back to the circuit. The third switching element 20 is connected so that the output current from the electric energy storage circuit can be supplied to the machining gap.
The output current is supplied in a pulse shape to the machining gap.

Also, as in the second embodiment, one FET
A series body of 136 and the resistor 137 constitutes a second processing circuit, and the second processing circuit superimposes the current from the first processing circuit to supply current to the processing gap.
It is connected in parallel to the first processing circuit. FIG.
In this embodiment, the electric energy storage circuit does not have the auxiliary power supply 28 required in the third embodiment shown in FIG.
However, since the rising of the current of the FET circuit can be performed sufficiently fast, it is not necessary to constantly perform the reflux. Rather, assisted by the high-speed operation by the FET, it is possible to eliminate the auxiliary power supply 28 for reflux and further reduce the size and cost.

FIG. 11 is a diagram showing the operation of the circuit of this embodiment. Although the command current waveform is a rectangular wave, the return current value gradually decreases as indicated by 150 because there is no auxiliary power supply 28 to supply energy during the idle time.
However, due to the rest of the return current and the high-speed operation by the FET, a sufficiently fast speed of rising and falling of the current can be obtained. In FIG. 11, 148a indicates an upper threshold, and 148b indicates a lower threshold.

FIG. 12 shows the operation when a kind of triangular wave is given as a current command. Although the return current decreases during the idle time as indicated by 153, a sufficient current is supplied because the rising current value of the next pulse is small. In FIG. 12, 151a is the upper threshold,
1b indicates a lower threshold.

FIG. 13 shows a case where the return current is higher than the rising current value of the pulse. In this case, the current is supplied from the FET circuit side until the return current value 156 exceeds the current command value 155. Although the current supplied from the FET is large, the time is short,
The element temperature does not rise so much as to cause a problem in operation as a semiconductor. Also, as shown in FIG. 6 of the second embodiment, in order to divide the amount of heat and the resistor directly inserted into the FET, it is not necessary to perform temperature design to prevent the temperature of the FET element from rising. Not difficult.
In this case, thermal energy consumed in the FET as a whole circuit can be minimized, high-speed response can be achieved with a simple circuit configuration, and current can be supplied according to an arbitrary waveform command. Further, since the circuit itself is constituted by a constant current circuit, extremely stable processing can be realized even when a minute current is supplied. 13, 154a is the upper threshold, 15
4b indicates a lower threshold.

As described above, the power supply device of the electric discharge machine according to the fourth embodiment uses a switching type power supply and has a circuit for returning excess current to the power supply. Very high efficiency, miniaturization of power supply,
Cost reduction can be easily realized. In addition, since a circuit using a semiconductor amplifier for compensating the current ripple of the switching power supply is added, there is no current ripple and stable processing can be realized even with a small current. Furthermore, since the semiconductor amplifier circuit is provided, the rise of current is sufficiently fast without using an auxiliary power supply in the freewheeling circuit, and the number of circuit components can be reduced and the circuit can be configured at low cost. Furthermore,
Since the width of the machining current pulse can be accurately controlled by adding the reflux circuit, stable and highly reproducible machining can be realized.

Embodiment 5 FIG. Next, a fifth embodiment of the present invention will be described below with reference to FIGS. This embodiment mainly describes the fifth invention. 14, the processing circuit includes a first current source 157 and a second current source 158. Here, the first current source 157 is the second current source 1
This is a power supply system with higher power supply efficiency than
The current source 158 is of a power supply type having a higher responsiveness than the first current source 157. In this embodiment,
The two current sources are superimposed on each other and supplied to the machining gap in order to take advantage of their respective features and compensate for other disadvantages.

In FIG. 14, reference numeral 102 denotes a current waveform command value,
161 is a signal representing the signal, 162 is a setting circuit, 174 is a subtraction circuit that subtracts δ1 from the command value signal 161 to obtain a new command value signal 163, and 190 is a command value signal 163.
And the first current source 15 detected by the current detector 160
7, a first signal adder / subtracter 165 for calculating a difference from a signal 164 representing the current supplied to the machining gap, an output signal 165 thereof, a signal 167 based on the signal 165, and a first current source 167. A first control circuit for controlling 157;
171 is a second signal adder / subtracter for calculating a difference between the command value signal 161 and the signal 164, 168 is an output signal thereof,
A second control circuit 169 outputs a signal 170 based on the signal 168 and controls the second current source 158.
The first current source 157 is a switching element that controls ON / OFF of the current supplied from the second current source 158 at a predetermined timing.

Next, the operation of this embodiment will be described with reference to FIG. That is, the signal 161 representing the current waveform command value is used as a reference, and the reference value is divided into two and the respective current sources 15
7, 158. At this time, the one first current source 157 subtracts the amount δ1 set by the setting circuit 162 from the reference signal 161 by the subtracting circuit 174 to obtain a new command value 163.
Supply as command value. Further, the difference between the reference current waveform command signal 161 and the current value supplied from the first current source 157, that is, the difference in the reference current waveform, is supplied as a command value to the second current source 158. This allows
The current value to the machining gap, which was insufficient in the first current source 157, is supplied from another second current source 158 capable of high-speed response, supplies a stable current to the machining gap, and realizes stable machining. can do.

The reason why the value subtracted from the reference command value by δ1 by the subtraction circuit 174 is used as the command value for the first current source 157 is to generate a shortage of current to some extent. Here, if there is no shortage current to be compensated by the second current source 158 and the current value of the first current source 157 exceeds the command value of the reference current waveform, the second current source with good responsiveness 158 cannot compensate,
That is, the current response to the machining gap becomes slow and machining becomes unstable.

Embodiment 6 FIG. Next, a sixth embodiment of the present invention will be described below with reference to FIGS. This embodiment mainly describes the sixth invention. In FIG. 15, the processing circuit comprises a first current source 157 and a second current source 158, as in the fifth embodiment. Here, the first current source 157 is of a power supply type having a higher power supply efficiency than the second current source 158, and the second current source 158 has a higher responsiveness than the first current source 157. It is of a good power supply type. In the present embodiment, the two current sources are superimposed and supplied to the machining gap in order to take advantage of their respective characteristics and to compensate for other disadvantages. In FIG. 15, reference numeral 172 denotes a setting circuit; and 173, a multiplying circuit which multiplies the command value signal 161 by an amount "k" exceeding "1" and exceeding "0" to obtain a new command value signal 163.
The other configuration is the same as that of the fifth embodiment, and the description is omitted.

Next, the operation of this embodiment will be described with reference to FIG. That is, the reference is made based on the original current waveform command value 102 and the signal 161 representing the same, and the reference value is divided into two and used as command values for the respective current sources 157 and 158. At this time, the first current source 157 includes the multiplication circuit 17
At step 3, a command value 163 is obtained by multiplying a reference signal 161 by a constant ratio "k" exceeding "1" and exceeding "0". Furthermore, the reference current waveform command signal 161 and the first
Is supplied as a command value to the second current source 158. As a result, the current value to the machining gap, which was insufficient in the first current source 157, is supplied from another second current source 158 capable of high-speed response, and a stable current is supplied to the machining gap. Processing can be realized.

The reason why the multiplication circuit 173 multiplies the value by “1” or less and exceeds “0” to obtain the command value for the first current source 157 is to generate a shortage of current to some extent. is there. Here, if there is no shortage current to be compensated by the second current source 158 and the current value of the first current source 157 exceeds the command value of the reference current waveform, the second current source with good responsiveness 158 cannot be compensated for, that is, the current response to the machining gap becomes slow and machining becomes unstable. By further multiplying by a constant, even if the shape of the reference current waveform 102 has a shape in which the current value is changed in the middle, the power supply of the first current source 157 is It can maximize the efficiency.

As described above, the power supply device of the electric discharge machine according to the fifth and sixth embodiments comprises a power supply having a current control method with high power supply efficiency and a power supply having a current control method with fast response. By combining them, it is possible to realize a power supply having high power supply efficiency, high responsiveness, and no current ripple or the like. For this reason, there is an effect that a small, inexpensive and stable processing can be realized.

Embodiment 7 FIG. Next, a seventh embodiment of the present invention will be described below with reference to FIGS. The seventh embodiment mainly describes the seventh invention. In FIG. 16, the processing circuit includes a first current source 157, a second current source 158, and a third current source 175. In particular, the third current source 175 has a Current source 157 and second
Are connected so as to supply a current in the opposite direction to the current source 158. Here, the first current source 157 is
8, a power supply system having higher power supply efficiency than the third current source 175, and the second current source 158 and the third current source 17
Reference numeral 5 denotes a power supply system having better responsiveness than the first current source 157.

In this embodiment, two types of current sources are used to take advantage of their respective characteristics and to compensate for other disadvantages.
Each current is superimposed and supplied to the machining gap while being superimposed negatively so as to reduce the excess. In FIG. 16, reference numeral 177 denotes a command value signal 161 and a signal 1 representing the current supplied to the machining gap from the first current source 157 detected by the current detector 160.
A first signal adder / subtracter for calculating and outputting the difference from
66 is a first control circuit that outputs a signal 167 based on the output signal of the first signal adder / subtractor 166 and controls the first current source 157. Second signal adder / subtracter for operation, 179
Is an output signal thereof, and 180 outputs signals 170 and 176 based on the signal 179, and outputs the second and third current sources 158, 158.
175 is a second control circuit.

Next, the operation of this embodiment will be described with reference to FIG. The reference current waveform command value 102 is simultaneously set to the first
Is the current command value to the current source 157. In the case of a switching power supply as shown in FIG. 16, the first current source 157
As a result, the waveform of the current supplied to the machining gap is represented by 167a and 167b as shown in FIG. That is, the waveform is different from the reference current waveform 102. Thus, the shortage 170 is supplied to the second current source 158 as a command value, and the excess 176 is supplied to the third current source 175 as a command value. The third current source 175 has a command value generated by the first current source 157 for any reason because the directions in which current can be supplied to the first and second current sources 157 and 158 are opposite. The difference between the current value and the current value can be compensated through the second and third current sources 158 and 175. Compensation by these power supplies with high response speeds improves the rise and fall speeds of the current supplied to the machining gap.Besides, the current supply becomes extremely constant, so that machining is stabilized and high-speed Processing can be realized.

As described above, the power supply device for an electric discharge machine according to the seventh embodiment combines a power supply with a current control method with high power supply efficiency and two power supplies with a current control method with fast response. Thus, a power supply with high power supply efficiency, high responsiveness, no current ripple, and the like, and a simple control circuit system can be realized. Therefore, a small, inexpensive and stable processing can be realized.

Embodiment 8 FIG. Next, an eighth embodiment of the present invention will be described with reference to FIGS. This embodiment mainly describes the eighth and ninth inventions. 20, a constant current supply unit 200 including a first switching element 201, a first diode 202, and a reactor 203 includes:
It is connected to a power supply E0 that supplies a DC voltage, and outputs a current to the output current interrupting unit 210. The constant current supply unit 200
, A step-down chopper including a first diode 202 and a reactor 203, and a second diode 204 is connected between the output and the input. Further, a current detector 205 for detecting a current of the reactor 203 is provided. Also, the output current intermittent unit 210
Comprises a second switching element 211, a series circuit of a third diode 212 and a voltage source 213, and a fourth diode 214. The output of the output current interrupting unit 210 supplies machining power between the electrode 1 provided in the machining fluid and the workpiece 2 to perform electric discharge machining.

In this device, the current of reactor 203 of constant current supply section 200 is detected by current detector 205, and signal 208 of output current command section 230 is added to signal 209 of ripple current setting section 250, and the sum is added. Signal 21
6 and the comparator 23 for comparing the signal of the current detector 205
2 Further, in this device, the first switching element 201 is controlled by the gate drive circuit 206, the output current of the constant current supply unit 200 is controlled to a predetermined current value, and the signal of the discharge command unit 240 is controlled by the gate drive circuit 215. By turning on / off the second switching element 211, the output current interrupting unit 210 is controlled.

In FIG. 21, (a) shows the discharge command section 24.
0 signal. The switching element 211 of the output current interrupting unit 210 is turned on by the pulse signal 260, and a no-load voltage 261 is applied between the electrode 1 and the workpiece 2 as shown in FIG. Thereafter, when a discharge occurs between the electrode 1 and the workpiece 2,
The no-load voltage is a discharge voltage like 262 in (b).

When a discharge occurs, the first switching element 201, the reactor 203, and the second switching element 2
11, a current flows from the power supply E0 to the electrode 1 and the workpiece 2 through the fourth diode 214. 208 in FIG. 21C
Indicates a signal of the output current level setting unit 230, and is output in synchronization with the start of discharge. Reference numeral 209 in FIG. 21D indicates a signal from the ripple current setting means 250, which is also output from the ripple current setting means 250 in synchronization with the start of discharge. Further, reference numeral 216 in FIG. 21E indicates a signal obtained by adding the signal 208 of the current level setting unit 230 and the signal 209 of the ripple current setting unit 250 (hereinafter, referred to as an addition signal).

When the discharge is started, the output current of the constant current supply unit 200 increases with the time constant of the inductance of the reactor 203 in the circuit, and the detected value of the output current is indicated by the signal 207. Addition signal 216 and current detection value 20
7 are continuously performed, and the detection signal 207 is
If it is less than 16, the comparator 232 outputs a signal that always turns on the first switching element 201, and outputs the detection signal 2
07 is greater than the sum signal 216, the comparator 232
Of the switching element 201 is output.

Next, the details of the constant current control will be described. FIG.
2 (a) is an enlargement of the waveform 263 of FIG. 21 (e) , and when the current value is smaller than the addition signal 216, 264
As shown in FIG. 7, the current detection value 207 is constantly increasing, and increases due to the time constant of the inductance. Addition signal 216
Is constantly changed from the start of discharge, and as shown by 265, if the current detection value 207 intersects with the waveform of the addition signal 216 during the increase, it becomes less than the addition signal 216 and turns off. Therefore, switching is forcibly repeated in the vicinity of the current level command unit 207, and finally falls within the current ripple set peak value 266. Current ripple setting value 2
Regarding the example 09, a triangular wave was used as the oscillation signal in the description of the present embodiment.
Even if a rectangular wave 267 and a sine wave 268 are used as shown in FIG.
Similar effects can be obtained.

Embodiment 9 FIG. Next, a ninth embodiment will be described with reference to FIGS. This embodiment mainly describes the eighth and tenth inventions. The current ripple setting means 270 in FIG. 23 has a Vf conversion unit that converts a signal of the current command unit 230 into a frequency (hereinafter, Vf conversion), and converts a signal 208 of the current setting unit 230 into a V-f. The circuit is configured to input a signal obtained by adding the Vf-converted signal 209 and the current setting value 208 to the comparator 232, and to input the signal to the comparator 232. The configuration is such that the frequency of the transmission signal 209 is changed. The other configuration is the same as that of the eighth embodiment, and the description is omitted.

FIG. 24 shows an example of Vf frequency conversion characteristics. The level of the signal 208 of the current setting unit 230 and the frequency of the transmission signal 209 are almost inversely proportional.
Is set so that the lower the level of the current is, the higher the frequency of the current is. When the level of the signal 208 is the maximum, the ripple is set to the maximum. When the level of the signal 208 is lowered to some extent, the frequency response of the first switching element 201 is limited, so that the frequency maximum value fmax is set so that the frequency does not increase even if the level of the signal 208 becomes lower than a certain level. Conversely, the frequency minimum value fmin is set so that the frequency does not exceed a certain value.

FIG. 25A shows the addition current 210 and the current detection signal 207 when the current peak is high. Addition signal 2
10 has a high peak and therefore has a low frequency, and therefore the switching period 271 of the first switching element 201 is long as shown in FIG. 2B, so that the on-time and off-time are long and the ripple ΔI1 is large. FIG.
(C) shows the addition current 216 and the current detection signal 207 when the current peak is low. When the current peak is low, the frequency of the addition signal 216 increases, and as shown in (d), the switching cycle 271 of the first switching element 201
Is shortened, and therefore the on-time and the off-time are shortened, so that the ripple ΔI2 can be reduced. By modulating the frequency of the addition signal according to the peak current in this manner,
Ripple can be reduced, and finally, uniform processing accuracy can be obtained.

Embodiment 10 FIG. Next, a tenth embodiment will be described with reference to FIGS. This embodiment mainly describes the eighth and eleventh inventions. In FIG. 26, the current ripple setting means 270 has a means for outputting a synchronization signal 273. Then, the synchronization signal 273 and the comparator 23
The second output signal 272 is input to the gate, and the first switching element 201 is driven by the gate output 281. The gate is connected to the first NA for inputting the synchronization signal 273 output from the current ripple setting means 270 and the output signal 272 of the comparator 232.
An ND circuit 276, a second NAND circuit 277 for inputting a synchronization signal 273 and an output signal 272 via an inverter 285, an output 279 of the first NAND circuit 276 to a reset terminal, and a second NAND circuit 277 And an RS-flip-flop for inputting the output 280 to the set terminal. Note that the other configuration is the same as in the ninth embodiment, and a description thereof will not be repeated.

FIG. 27 shows a timing chart according to the tenth embodiment, and the operation will be described. (A) is a rectangular wave synchronization signal 273 from the ripple current setting means 270;
(B) shows the signal 20 from the ripple current setting means 270.
9, (c) shows the detection signal 207 of the current waveform and the addition signal 2
16, (d) is an output signal 272 of the comparator 232.
When the current detection value 207 exceeds the addition signal 216, the output of the comparator goes low and the first switching element 201 is turned off. However, during normal switching, noise 274 is generated as shown in (c). I do.

For this reason, as shown in FIG.
Always compares the current detection value 207 with the addition signal 216, so that the noise 274 is compared with the addition signal 216,
In the output signal 272 of 32, an on / off repeated portion 275 occurs due to the influence of the noise 274, which causes a malfunction. Therefore, as shown in (e) and (f), the output signal 272 of the comparator 232 and the current ripple setting means 27
The first NAND circuit 276, the inverter 285, and the second NAND circuit 27
7 and the first and second NAND circuits 276 and 277
27 (g) by inputting the output signals 279 and 280 to the flip-flop 278 so that the flip-flop 278 is inverted only once for H and L of the rectangular wave. 281 can be obtained, and the unstable operation of the noise 274 can be eliminated. Therefore, noise 274 is input to the input of the comparator 232.
Even if it enters, accurate switching operation can be expected.

Embodiment 11 FIG. Next, an eleventh embodiment will be described with reference to FIGS. This embodiment mainly describes the eighth and twelfth inventions. Since the configuration of the first circuit 290 and the configuration of the second circuit 291 are the same as the circuit configuration described in the eighth embodiment, detailed description will be omitted. FIG.
8, the first circuit 290 and the second circuit 291 are connected in parallel to the machining gap, and the detecting means 20 for detecting the output current of the first constant current supply unit 200
5, and a detection unit 205 for detecting the output current of the second constant current supply unit 300. The output of the output current level setting means 230 for instructing the output currents of the first and second constant current supply units is used as the first ripple current setting means for instructing the ripple current of the output current of the first constant current supply unit 200. 250 (hereinafter referred to as a first added signal 35).
1) The output of the detection means 205 for detecting the output current of the first constant current supply unit 200 (hereinafter, the first detection signal 35
2) is compared with the first comparison device 232.

The output of the detecting means 305 for detecting the output current of the second constant current supply unit 300 (hereinafter, a second detection signal 353) and the ripple current of the output current of the first constant current supply unit 200 Is inverted by the inverting means 354. The set value of the inverting means 354 commands a set value having a phase difference of 180 degrees, and the inverted signal is added to the set values of the first and second output current level setting means (hereinafter, a second added signal 355). , And the second comparator 332 compares the sum signal 304 with the value detected by the second detector.

Next, the operation will be described with reference to the timing chart of FIG. (A) is an ON signal of the second switching element 215 of the first constant current circuit 200 and the second switching element 315 of the second constant current circuit 300, which are turned on by a command 360 of the discharge command unit 240. 3B, the output signal 208 is output from the output current level setting means 230 in synchronization with the start of the discharge. At this time,
The output current level signal 208 is set to a value that is about 1/2 times the desired output value. (C) shows the detection signal 352 of the first constant current supply unit and the first constant current supply unit.
Of the first comparison device 232
Is compared with the first addition signal 351. If the detection signal 352 of the first constant current supply unit 200 is equal to or smaller than the first addition signal 351, the gate drive circuit 206 causes the first switching element When the first output signal 352 is equal to or more than the first addition signal 351, the gate drive circuit 206 turns off the first switching element 201.

(D) shows the second output signal 353 and the second addition signal 355. The second comparator 332 compares the second output signal 353 with the second addition signal 355, and
Is less than or equal to the second addition signal 355,
In the gate drive circuit 306, the second constant current supply device 30
On the other hand, if the second output signal 353 is equal to or larger than the second addition signal 355, the gate drive circuit 306 turns off the first switching element 301.

30A shows the output current 362 of the first circuit, and FIG. 30B shows the output current 363 of the second circuit. FIG. 30B shows the output current of the circuit. By the two switching elements 211 and 311, a pulse having a desired pulse width determined by the output 360 of the discharge command section 250 flows through the gap formed between the electrode 1 and the workpiece 2. Output 35 of constant current supply unit 200 of first circuit 290
2, the ripple is determined by the addition signal 351.
The output current 362 of the first circuit 290 has a ripple width of ΔI1. The output 353 of the constant current supply unit of the second circuit 291 is based on the addition signal 351 for controlling the ripple of the constant current supply unit 200 of the first circuit 290 and the second addition signal 355 which is 180 ° out of phase. Controlled, the second
The ripple of the output current 363 of the circuit 291 of the first circuit is flowed between the poles 180 ° out of phase with the ripple of the output current 362 of the first circuit.

At this time, the ripple ΔI2 of the output current 363
Has substantially the same width as the ripple ΔI1 of the first output current. Therefore, the machining gap current 361 flowing between the poles is a current obtained by adding the output currents 362 and 363, and shows a role of canceling out the ripples of the output currents 362 and 363. The ripple ΔI3 is so incomparable as ΔI1 and ΔI2. Will be very small. With this circuit method, a low ripple current can be obtained, and a discharge current having a shape almost similar to the current level command setting can be obtained.

Embodiment 12 FIG. A twelfth embodiment will be described with reference to FIGS. This embodiment mainly describes the thirteenth invention. In FIG. 31, 400 is a timer,
It outputs a signal 401 as shown in FIG. The other configuration is substantially the same as that of the eighth embodiment except that the ripple current setting means 250 is not provided, and the description is omitted.

Next, the operation will be described with reference to the timing chart of FIG. Reference numeral 208 in (a) denotes a signal from the output current level setting unit 230, which is output in synchronization with the start of discharge. Reference numeral 401 in FIG. 32B indicates the output of the timer 400. When the discharge is started, the output current of the constant current supply unit 200 increases by the time constant of the inductance of the reactor 203 in the circuit, and if the detection signal 207 exceeds the signal 208, the comparator 232 switches the first switching element 201 A signal for turning off is output. When a predetermined time has elapsed after the turning off, the timer 400 outputs a signal for turning on the first switching element 201. Then, the detection signal 207 becomes the signal 2
08, the comparator 232 outputs a signal for turning off the first switching element 201. As a result, the detected value of the current is indicated by the signal 207 in FIG. Also in this circuit system, the inductance value of the reactor 203, the ON / OF of the timer,
By appropriately selecting the F time, a low ripple current can be obtained, and a discharge current having a shape close to the current level command setting can be obtained.

Embodiment 13 FIG. Hereinafter, a thirteenth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the fourteenth, fifteenth, and
And a sixteenth invention will be mainly described. FIG.
Shows a main circuit diagram according to a thirteenth embodiment.
E1 is a first DC power supply, 201 is a first switching element, and the first switching element 201 is switched by a gate drive circuit 206. Reactor 203
Is connected between the first switching element 201 and the second switching element 211, and the electrode 1 and the workpiece 2 are connected to the second switching element 211 and the first DC power supply E1. The first diode 202 is connected between a connection point between the first switching element 201 and the reactor 203 and the first DC power supply E1.
Is connected between a connection point between the first power supply E1 and the first switching element 201 and a connection point between the reactor 203 and the second switching element 211 in a direction in which current flows to the first DC power supply E1. .

A series body of the third diode 212 and the DC power supply 213 is connected between the electrode 1 side of the second switching element 211 and the negative voltage side of the first DC power supply E1. The current detector 205 is connected to detect a current flowing through the reactor 203. The series body of the second DC power supply E2, the third switching element 501, and the diode 502 having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap is provided by the first diode 2
02 in parallel. This third switching element 5
01 is switched by the gate drive circuit 503.
In this embodiment, the first switching element 2
01, the first diode 202 and the reactor 203 constitute a constant current supply unit 200. The output current intermittent unit 210 is a series circuit of the second switching element 211 and the third diode 212 and the DC power supply 213. It consists of.

FIG. 34 shows the gate drive circuit 50 shown in FIG.
In the figure, a first comparator 504 compares a current command value S1 with a current detection value I1 of a current detector 205, and a timer circuit 5
A signal is output to twelve input terminals. The second comparator 505 compares an overcurrent command value 507 obtained by connecting a DC voltage 506 in series with the current command value S1 to a current detection value I1 of the current detector 205, and resets the reset terminal R of the first flip-flop 508. Output to The first comparator 5
The output of 04 is inverted by an inverter 509 and connected to the set terminal S of the first flip-flop 508.

On the other hand, the discharge signal H output from the NC device
1 switches the second switching element 211 by the gate drive circuit 215. Further, the discharge signal H1, the output of the timer circuit 512, and the first flip-flop 5
The AND condition with the output 08 is taken by the AND circuit 511, and the first switching element 201 is switched by the gate drive circuit 206. The AND condition between the discharge signal H1 and the output of the first flip-flop 508 is set to A.
The third switching element 501 is switched by the gate drive circuit 503 by the ND circuit 510.

FIGS. 35 and 36 show specific examples of the timer circuit 512 in FIG. An example of the timer circuit 512 in FIG. 35 is that the first comparator 50 is connected to the input terminal IN.
4 output is connected. The MOSFET 512A is connected to the resistor 5
The capacitor 512C of the time constant circuit constituted by the capacitor 12B and the capacitor 512C is short-circuited and opened. FIG. 37 shows the input signal (a) and the output signal (b). In the input (a), when the output of the first comparator 504 becomes H at 600, the MOSFET 512A turns on and shorts the capacitor 512C. Therefore, the output (b) becomes L.

Also, in the input (a), at 601 the first
When the output (b) of the comparator 504 becomes L, MO
Since the SFET 512A is turned off and the capacitor 512C is opened, the threshold of the buffer 512D is exceeded after a predetermined time 603 by the time constant circuit constituted by the resistor 512B and the capacitor 512C, and the output (b) becomes H at 602. That is, the output of the first comparator 504 is H
, The output OUT becomes L, and the output OU is output after a certain time from when the output of the first comparator 504 becomes L.
T becomes H. Timer circuit 512 operates in this manner. The example of the timer circuit 512 in FIG. 36 is configured by a logic circuit including a monostable multivibrator 512E and a flip-flop 512F. The operation of the output OUT according to the time set in the monostable multivibrator 512E is illustrated in FIG. Is equivalent to

The timing chart and waveform chart shown in FIG. 38 show the operation of the thirteenth embodiment. In FIG. 38, (a) is a discharge signal H1, (b) is an output voltage waveform, (c) is a waveform of a current command value S1 output from a control device (not shown) of the electric discharge machine, (d) Is the output current waveform, and (e) is the ON / O of the first switching element 201.
FF situation, (f) shows O of third switching element 501
N / OFF situation, (g) is a current passing situation of the diode 202, (h) is a current passing situation of the diode 502,
(I) is the output state of the first comparator 504, (k)
Indicates the output status of the timer circuit 512, (l) indicates the output status of the first flip-flop 508, and (m) indicates the output status of the second comparator 505.

When the discharge signal H1 is turned on at 700 in FIG. 38A, the second switching element 211 is turned on by the gate drive circuit 215. At this time, the first in FIG.
Since the switching element 201 is turned on as shown in (e), the voltage of the first DC power supply E1 is applied between the electrode 1 and the workpiece 2 as shown in (b). The space between the electrode 1 and the workpiece 2 is filled with a working liquid such as oil or water, and the gap is very precisely controlled by a servo mechanism and a numerical controller or the like, which are not described. When dielectric breakdown of the minute gap occurs, the electrode 1
A discharge is generated between the workpiece 2 and the workpiece 2. In this case, FIG.
701 of (a), the output voltage of (b) becomes the discharge voltage of 702. This discharge voltage is almost constant at about 25 to 30 volts. A current starts to flow between the electrode 1 and the workpiece 2 at the same time as the occurrence of the discharge, but 703 in (d) passes through the first DC power source E1, the first switching element 201, the reactor 203, and the second switching element 211. Since the voltage of the first DC power supply E1 is about 80 volts, which is higher than the discharge voltage 702, the rise of the current is fast.

When the output current, that is, the current of the reactor 203 reaches the current command value S1, the output of the first comparator 504 becomes H as shown at (i) in 704. Therefore, the output of the timer circuit 512 shown in (k) becomes L, and the first switching element 201 is turned off as shown in (e). When the output of the first comparator 504 becomes H, the output of the timer circuit 512 becomes L for a preset time indicated by 705 in (k), and thereafter becomes H at 706, so that the first switching element 201 is turned on again. Turn on.

The set time of the timer circuit 512, that is, the period 70 during which the first switching element 201 is off.
In 5, a current is supplied between the electrode 1 and the workpiece 2 from the second DC power supply E <b> 2 through the third switching element 501, the diode 502, and the reactor 203 which are already turned on. Since the second DC power supply E2 is set to be equal to or slightly lower than the discharge voltage 702, the output current decreases little as indicated by 707 in (d). This is reactor 203
This is because the change in current is small because the voltage between the terminals becomes low. By repeating this, the output current follows as shown in (d) according to the value of the current command value S1.

When the value of the current command value S1 becomes a constant value as indicated by 703 in (c), the output current decreases slowly as indicated by 709 in (d), but increases slowly as indicated by 710 in (d). It will be faster. At this time, the decreasing time of 709 is the same setting time of the timer circuit 512 as that of 707. Therefore, even if the value of 710 becomes close to zero, the switching frequency of the first switching element 201 becomes less than 70.
It does not fall below 9 cycles. Further, since the current 709 is slowly reduced, the ripple of the output current is reduced. Therefore, by connecting the second DC power supply E2 while the first switching element 201 is off for a certain period of time, a power supply device for an electric discharge machine having an output current waveform with little ripple can be configured.

FIG. 39 is a waveform chart and a timing chart for explaining an operation when a short circuit occurs between the electrode 1 and the workpiece 2 during generation of electric discharge. When a short circuit occurs at 711 when the discharge current flows as in FIG. 38, the output voltage (b) becomes equal to or lower than the voltage of the second DC power supply E2. To increase. Since this is also the current of the reactor 203,
This current increases and the overcurrent detection value 507 (d) 71
3, the overcurrent command value 5 obtained by adding the DC power supply 506 to the current detection value I1 of the current detector 205 and the current command value S1.
The output of the second comparator 505 for comparing 07 becomes H.

Therefore, the output Q of the first flip-flop 508 becomes L, and the third switching element 501 becomes A
It is turned off by the ND circuit 510. At this time, the first
Of the switching element 201 is already off. Therefore, the output current is the second diode 202, the reactor 20
3, supplied through the second switching element 211,
It decreases like 14. When the output current further decreases and decreases to the current command value S1, the output of the first comparator 504 becomes L at (i) at 715, and the signal inverted by the inverter 509 sets the first flip-flop 508. The output Q is set to H. As a result, the third switching element 501 turns on, and the output current increases. In this manner, when the electrode 1 and the workpiece 2 are short-circuited, the current command value S1 and the overcurrent command value 507
Since the output current increases and decreases between them and does not increase rapidly as a short-circuit current, it is possible to prevent the electrode 1 or the workpiece 2 from being damaged by a large current.

When the short-circuit state is recovered for some reason,
At 716, the output voltage returns to the discharge voltage as indicated by 717 in (b). Therefore, the output current of (d) decreases rapidly, and when the output current decreases to 718 of the current command value S1, the output of the first comparator 504 becomes L,
9, the first flip-flop 508 is set, the output Q of the first flip-flop 508 becomes H, and the third switching element 5
01 turns on, and the output current slowly decreases as indicated by 719. The timer circuit 512 includes a first comparator 504
Is output for L for a set time after the output becomes low, and returns to the normal operation.

FIG. 40 shows the gate drive circuit 2 shown in FIG.
FIG. 3 shows a modified example of the control circuit of FIG.
34 shows a method of adding the DC voltage 506 of the circuit 4 to the current command value S1 by the adder 513 to obtain the overcurrent command value 507, and can perform the same operation as the circuit of FIG.

FIG. 41 is a waveform chart showing the measured actual output current when the peak value of the current command value S1 is 35 A in the device according to the thirteenth embodiment. (A)
Represents a change in the current command value S1, and the peak value is 35A. (B), when the first DC power supply E1 is 80V and the voltage of the second DC power supply E2 is 0V, (c) is when the first DC power supply E1 is 80V and the voltage of the second DC power supply E2 is 15V
(D) shows that the first DC power source E1 is
Shows the respective waveforms when the voltage of the DC power supply E2 is 30V. (B) When the voltage of the second DC power supply E2 is 0 V, that is, in the conventional case where the second DC power supply E2 does not exist,
When the voltage of the second DC power supply E2 in FIG.
Is 7 A, and when the voltage of the second DC power supply E <b> 2 in (d) is 30 V, the ripple 606 is 2 A, and it can be seen that the ripple is extremely small.

FIG. 42 is a waveform chart showing the measured actual output current when the peak value of current command value S1 is 10 A in the device according to the thirteenth embodiment.
(A) is a change in the current command value S1, and the peak value is 10A.
It is. (B) shows a case where the first DC power supply E1 is 80 V and the second
(C), when the voltage of the first DC power supply E1 is 80V and the voltage of the second DC power supply E2 is 1
(D) when the first DC power supply E1 is 80 V,
The respective waveforms when the voltage of the second DC power supply E2 is 30 V are shown. (B) The voltage of the second DC power supply E2 is 0 V
At that time, the ripple 604 was close to 10A,
When the voltage of the second DC power supply E2 in (c) is 15 V, the ripple 605 is 5 A, and when the voltage of the second DC power supply E2 in (d) is 30 V, the ripple 606 is almost zero, and the ripple becomes very small. Understand that

In particular, in (b), the output current value is zero in the rising portion 607 of the current, and when the electric discharge machining is performed with such a waveform, the generated discharge is stopped and the command value (a ) Cannot be output. On the other hand, the second DC power supply E2 shown in FIG.
In this case, a current waveform close to the command value can be obtained as shown by 608, and the ripple is almost zero as shown by 606. Here, the second DC power supply E2 is selected to be 30 V, but the third switching element 501, the diode 50
2. Since there is a DC resistance value of the reactor 203 and an ON voltage of the second switching element 211, actually, a voltage of a value obtained by subtracting the ON voltage from 30V of the second DC power supply E2 is applied to the electrode 1 and the workpiece. It becomes a DC voltage source that tries to flow a current with respect to the voltage between the two. The intended purpose can be achieved even when the voltage supplied between the electrodes from the second DC power supply E2 is higher than the discharge voltage by about 1 to 2 V.

Embodiment 14 FIG. Next, a fourteenth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the fourteenth, the seventeenth, and the first
This mainly describes the eighth and nineteenth inventions.
FIG. 43 shows a main circuit diagram according to the fourteenth embodiment, in which E1 is a first DC power supply, 201 is a first switching element, and this first switching element 201 is switched by a gate drive circuit 206. . Reactor 2
03 is connected between the first switching element 201 and the second switching element 211, and the electrode 1 and the workpiece 2 are connected to the second switching element 211 and the first DC power supply E1. The first diode 202 is connected between the connection point between the first switching element 201 and the reactor 203 and the first DC power supply E1, and the second diode 20
4 is a first power supply E1 and a first switching element 201
Is connected between the connection point of the first DC power supply E1 and the connection point of the reactor 203 and the second switching element 211.
Connect in the direction of flow.

Further, the series body of the third diode 212 and the DC power supply 213 is connected between the electrode side of the second switching element 211 and the negative voltage side of the first DC power supply E1. The current detector 205 is connected to detect a current flowing through the reactor 203. The series body of the second DC power supply E2, the third switching element 501, and the diode 502 having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap is provided by the first diode 2
02 in parallel. This third switching element 5
01 is switched by the gate drive circuit 503.
A series body of a third DC power supply E3, a fourth switching element 514, and a diode 515 having a voltage capable of supplying a voltage higher than the discharge voltage to the machining gap and lower than the voltage supplied from the first DC power supply, One diode 20
2 in parallel. This fourth switching element 51
4 is switched by the gate drive circuit 516.

FIG. 44 shows the gate drive circuit 50 shown in FIG.
3, 516, 206, and 215. In the figure, a first comparator 504 compares a current command value S1 with a current detection value I1 of a current detector 205, and outputs a signal to an input terminal of a timer circuit 512. Is output. The second comparator 505 includes an overcurrent command value 507 obtained by connecting a DC voltage 506 in series to the current command value S1 and a current detector 205
And outputs the result to the reset terminal R of the first flip-flop 508. The output of the first comparator 504 is inverted by an inverter 509 and connected to the set terminal S of the first flip-flop 508.

On the other hand, the discharge signal H1 is
15 switches the second switching element 211. The AND condition of the current increase signal H2, the output of the timer circuit 512, and the discharge signal H1 is determined by the AND circuit 519.
Then, the first switching element 201 is switched by the gate drive circuit 206. An OR circuit 5 for obtaining an OR condition of the discharge signal H2 and the output of the timer circuit 512
An AND condition between the output of the output signal 17, the discharge signal H 1, and the output of the first flip-flop 508 is taken by the AND circuit 518, and the fourth switching element 514 is switched by the gate drive circuit 516. Also, the discharge signal H1
An AND condition between the output of the first flip-flop 508 and the output of the first flip-flop 508 is taken by the AND circuit 510, and the gate drive circuit 503
Switches the third switching element 501.

The timing chart and waveform chart shown in FIG. 45 show the operation of the fourteenth embodiment. In FIG. 45, (a) is a discharge signal H1, (b) is an output voltage waveform, (c) is a waveform of a current command value S1 output from a control device (not shown) of the electric discharge machining device, (d) Is the output current waveform, and (e) is the ON / O of the first switching element 201.
FF situation, (f) shows O of third switching element 501
N / OFF situation, (g) is a current passing situation of the diode 202, (h) is a current passing situation of the diode 502,
(I) is the output state of the first comparator 504, (j)
Is the current increase signal H2, (k) is the output state of the timer circuit 512, and (n) is the ON state of the fourth switching element 514.
The OFF state and (o) show the current passing state of the diode 515, respectively.

When the discharge signal H1 is turned on at 700 in FIG. 45A, the second switching element 211 is turned on by the gate drive circuit 215. Also, the current increase signal H
2 also turns on at 700. At this time, the first switching element 201 in FIG. 43 is turned on as shown in FIG. 43E, and the voltage of the first DC power supply E1 is applied between the electrode 1 and the workpiece 2 as shown in FIG. Join as. The space between the electrode 1 and the workpiece 2 is filled with a working liquid such as oil or water, and the gap is very precisely controlled by a servo mechanism and a numerical controller or the like, which are not described. When dielectric breakdown occurs in the minute gap, discharge occurs between the electrode 1 and the workpiece 2. At this time, the output voltage is 701 in FIG. 45A, but the output voltage in FIG. This discharge voltage is 25 to 3
It is almost constant at about 0 volt. A current starts to flow between the electrode 1 and the workpiece 2 at the same time as the occurrence of electric discharge.
3 is a first DC power supply E1, a first switching element 20
1, reactor 203, second switching element 211
And the voltage of the first DC power supply E1 is about 80 volts, which is higher than the discharge voltage 702, so that the current rises quickly.

When the output current, that is, the current of the reactor 203 reaches the current command value S1, the output of the first comparator 504 becomes H as shown in (i) in 704. Therefore, the output of the timer circuit 512 shown in (k) becomes L, and the first switching element 201 is turned off as shown in (e). When the output of the first comparator 504 becomes L, the output of the timer circuit 512 becomes L for a preset time indicated by 705 in (k) and then becomes H at 706, so that the first switching element 201 restarts. Turn on.

The set time of the timer circuit 512, that is, the period 70 during which the first switching element 201 is off.
5 is the fourth switching element 514 and the diode 5 already turned on from the third DC power source E3 because the fourth switching element 514 shown in (n) is already on.
15, reactor 203, second switching element 21
1, an electric current is supplied between the electrode 1 and the workpiece 2. Since the third DC power supply E3 is set slightly higher than the discharge voltage 702, the output current gradually increases as indicated by 707 in (d). This is because the voltage between terminals of the reactor 203 is slightly higher, and the current gradually increases. By repeating this, the output current follows as shown in (d) according to the value of the current command value S1.

If the current increase signal H2 in (j) is changed to L at 720 in which the current command value S1 in (c) of FIG. 45 becomes constant from an increase, the output current decreases when the third switching element 501 is turned on. The third DC power supply E3 is connected to the fourth switching element 51
4 is turned on, so the increase 721 is also slow. At this time, the decreasing time of 709 is the same setting time of the timer circuit 512 as that of 707, and the rate of current increase is slow. Therefore, the switching frequency is about twice the cycle of 709, and the ripple of the output current is reduced. Is small,
Even if the switching frequency is low and the inductance value of the reactor 203 is small, a power supply device for an electric discharge machine having an output current waveform with little ripple can be configured.
In particular, when the current increase signal H2 is turned on and the current command value is increased, the third switching element 201 is turned off even if the first switching element 201 is turned off.
Since the current is supplied from the DC power supply E3 and the output current is constantly increasing, it is possible to configure a power supply device for an electric discharge machine having an output current waveform with little ripple.

Embodiment 15 FIG. Next, a fifteenth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the fourteenth, twentieth and
This mainly describes the twenty-first invention. FIG. 46 shows a main circuit diagram according to the fifteenth embodiment.
1 is a first DC power supply, 201 is a first switching element, and the first switching element 201 is switched by a gate drive circuit 206. The reactor 203 is connected between the first switching element 201 and the second switching element 211, and the electrode 1 and the workpiece 2 are connected to the second switching element 211 and the first DC power supply. The first diode 202 is a first switching element 201
The second diode 204 is connected between a connection point between the power supply and the reactor 203 and the first DC power supply E1.
Between the power supply E1 of the first switching element 201 and the reactor 203 and the second switching element 211.
Are connected in a direction in which a current flows to the first DC power supply E1.

Further, a series body of the third diode 212 and the DC power supply 213 is connected between the electrode 1 side of the second switching element 211 and the negative voltage side of the first DC power supply E1. The current detector 205 is connected to detect a current flowing through the reactor 203. The series body of the second DC power supply E2, the third switching element 501, and the diode 502 having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap is provided by the first diode 2
02 in parallel. This third switching element 5
01 is switched by the gate drive circuit 503.
Variable fourth DC power supply E4 and fifth switching element 5
A series body of 21 and a diode 522 is connected in parallel to the first diode 202. The fifth switching element 521 is switched by the gate drive circuit 520.

FIG. 47 shows the gate drive circuit 50 shown in FIG.
In the drawing, a first comparator 504 compares a current command value S1 with a current detection value I1 of a current detector 205 and outputs a signal to an input terminal of a timer circuit 512. I do. The second comparator 505 compares the overcurrent command value 507 obtained by connecting the DC voltage 506 in series to the current command value S1 with the current detection value I1 of the current detector 205, and outputs the result to the reset terminal R of the first flip-flop 508. I do. The first comparator 5
04 output is inverted by an inverter 509 and
To the set terminal S of the flip-flop 508.

On the other hand, the discharge signal H1 is supplied to the gate drive circuit 21.
5, the second switching element 211 is switched. An AND condition between the no-load voltage signal H3 and the discharge signal H1 supplied from the control device of the electric discharge machine is taken by the AND circuit 524, and the first switching element 201 is switched by the gate drive circuit 206. An AND condition of the output of the timer circuit 512, the discharge signal H1, and the output of the first flip-flop 508 is taken by the AND circuit 523, and the fifth switching element 521 is switched by the gate drive circuit 520. Also, the discharge signal H
An AND condition between AND 1 and the output of the first flip-flop 508 is taken by the AND circuit 510, and the gate drive circuit 50
3, the third switching element 501 is switched.

The timing chart and waveform chart shown in FIG. 48 show the operation of the fifteenth embodiment. 48, (a) is a discharge signal H1, (b) is an output voltage waveform, (c) is a waveform of a current command value S1 output from a control device (not shown) of the electric discharge machining device, (d) Is the output current waveform, and (e) is the ON / O of the first switching element 201.
FF situation, (f) shows O of third switching element 501
N / OFF situation, (g) is a current passing situation of the diode 202, (h) is a current passing situation of the diode 502,
(I) is the output state of the first comparator 504, (j)
Is the no-load voltage signal H3, (k) is the output state of the timer circuit 512, and (n) is the output state of the fifth switching element 521.
N · OFF status, and (o) shows the current passing status of the diode 522, respectively.

When the discharge signal H1 is turned on at 700 in FIG. 48A, the switching element 211 is turned on by the gate drive circuit 215. Also, the no-load voltage signal H3 is turned on at 700. At this time, the switching element 201 in FIG. 46 is turned on as shown in FIG. 46E, so that the voltage of the first DC power source E1 is applied between the electrode 1 and the workpiece 2 as a no-load voltage as shown in FIG. The current command value S1 in this embodiment may have a waveform that commands only the peak of the discharge current as shown in (c).

The space between the electrode 1 and the workpiece 2 is filled with a working fluid such as oil or water, and the gap is very precisely controlled by a servo mechanism and a numerical controller, etc., which are not described. When dielectric breakdown occurs in the minute gap, discharge occurs between the electrode 1 and the workpiece 2. At this time, the output voltage is 701 in FIG. 48, but the output voltage in FIG. This discharge voltage is almost constant at about 25 to 30 volts. A current starts to flow between the electrode 1 and the workpiece 2 simultaneously with the occurrence of the discharge, and the no-load voltage signal H3 becomes L as shown in (j). Therefore, the first switching element 201 is turned off as shown in FIG.

722 of (d) is the fourth DC power supply E4, the fifth switching element 521, the reactor 203, the second
, The voltage of the fourth DC power supply E4 is a preset voltage (about 25 to 100 volts), so that the voltage of the fourth DC power supply E4, 7 of (d) determined by the difference voltage between the voltage between the object 2 and the inductance value of the reactor 203
The output current increases at the rise of the output current 22.
723 of (d) shows a case where the voltage of the fourth DC power supply E4 is increased. By changing the voltage of the fourth DC power supply E4, an output current rising with an arbitrary gradient can be obtained. Further, since there is no ripple at the rise of the output current, the output current does not become zero even when the output current is very small, and stable electric discharge machining can be performed.

Next, when the output current, that is, the current of the reactor 203 reaches the current command value S1, the first
The output of the comparator 504 becomes H as shown in (i). Therefore, the output of the timer circuit 512 shown in (k) is L
, And the fifth switching element 521 is turned off as shown in (n). When the output of the first comparator 504 becomes L, the output of the timer circuit 512 becomes L for a preset time indicated by 705 in (k).

The set time of the timer circuit 512, that is, the period 70 during which the fifth switching element 521 is off.
5 shows that, since the third switching element 501 shown in (f) is already turned on, the second DC power supply E2 passes through the third switching element 501, the diode 502, the reactor 203, and the electrode 1 and the workpiece. Current is supplied between the two. Since the second DC power supply E2 is set slightly lower than the discharge voltage 702, the output current gradually decreases as indicated by 727 in (d). Thereafter, the output of the timer circuit 512 becomes H at 726, so that the fifth switching element 521
Turns on again and the current increases. By repeating this, the output current follows as shown in (d) according to the value of the current command value S1.

According to the fifteenth embodiment, when the current increases, there is no ripple since the current increases at a constant gradient like 722 and 723, and the fifth switching element 521 is always turned on during this period. Therefore, there is no need to perform switching. After the output current reaches the command value, the output current decreases slowly as indicated by 727, and the time during which 727 decreases is the set time of the timer circuit 512 at 705, and the switching frequency is about 705. Even when the cycle is short, the ripple of the output current is small, the switching frequency is low, and the inductance value of the reactor 203 is small, it is possible to configure a power supply device for an electric discharge machine having an output current waveform with a small ripple.

Embodiment 16 FIG. Next, a sixteenth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the fourteenth, the twenty-second, and the twenty-second
This mainly describes the twenty-third invention. FIG. 49 shows a main circuit diagram according to the sixteenth embodiment.
In the thirteenth embodiment, a series body of a fifth DC power supply E5, a sixth switching element 526, and a resistor 529 is connected in parallel to a machining gap formed by the electrode 1 and the workpiece 2. is there. The second switching element 211 is provided with a diode 527 for preventing reverse current. Fifth DC power supply E
5 has a voltage capable of supplying a voltage higher than the voltage supplied from the first DC power supply to the machining gap.
In the figure, reference numeral 525 denotes a gate drive circuit of the switching element 526.

FIG. 50 shows the gate drive circuit 50 shown in FIG.
3, 206, 215, and 525. In the figure, the control circuit shown in FIG.
The AND condition between the high voltage pulse signal H4 and the discharge signal H1 is A
The sixth switching element 526 is controlled by the gate drive circuit 525 by the ND circuit 528. Note that the other configuration is the same as that of the control circuit shown in FIG. 34 according to the thirteenth embodiment, and a description thereof will not be repeated.

The timing chart and waveform chart shown in FIG. 51 show the operation of the sixteenth embodiment. Note that FIG.
(A) is the discharge signal H1, (b) is the output voltage, (d)
Shows the output current, (e) shows the ON / OFF state of the first switching element 201, (f) shows the high-voltage pulse signal, and (g) shows the ON / OFF state of the sixth switching element 526. When the discharge signal H1 is turned on at 700 in FIG. 51A, the switching element 211 is turned on by the gate drive circuit 215. At this time, since the switching element 201 in FIG. 49 is turned on as shown in FIG. 49E, the voltage of the first DC power source E1 is applied between the electrode 1 and the workpiece 2 as shown in FIG.
It is applied as a no-load voltage like 28.

The space between the electrode 1 and the workpiece 2 is filled with a working fluid such as oil or water, and the gap is very precisely controlled by a servo mechanism and a numerical controller which are not described. When dielectric breakdown occurs in the minute gap, discharge occurs between the electrode 1 and the workpiece 2. However, in rare cases, electric discharge may not easily occur, and an unstable electric discharge machining state may occur. In order to prevent such a situation, if the discharge does not occur even after the elapse of the time 729 from the turning on of the discharge signal H1, the high voltage pulse signal H4 is output at 730 as shown in FIG. , (G) turn on the sixth switching element 526 to output the voltage of the fifth DC power supply E5. This voltage is shown at 731 in FIG. The actual voltage of the fifth DC power supply E5 is as high as 150 to 300 volts.

When a discharge occurs, the high-voltage pulse H4 becomes 70
At 1, the voltage becomes L, the sixth switching element 526 in (g) is turned off, and the voltage of the first DC power supply E 1 is applied between the electrode 1 and the workpiece 2 by the already turned on first switching element 201. And the output current increases.
At the moment when this discharge occurs, a current flows through the resistor 529, but since the sixth switching element 526 is turned off immediately, the resistor 529 consumes little power. The voltage of the DC power supply E5 is 150 to 300 volts and the first DC power supply E5.
Since the voltage of 1 is higher than 80 volts, electric discharge is reliably generated and electric discharge machining becomes stable. The other operations are the same as in the thirteenth embodiment, and a description thereof will not be repeated.

The sixteenth embodiment is different from the thirteenth embodiment in that a series body of a fifth DC power supply E5, a sixth switching element 526 and a resistor 529 is added to the electrode 1 and the workpiece 2 In the fourteenth embodiment or the fifteenth embodiment, the connection in parallel with the processing gap formed by
In this embodiment, a series body of a fifth DC power supply E5, a sixth switching element 526, and a resistor 529 is connected in parallel to a machining gap formed by the electrode 1 and the workpiece 2. Has the same effect. Even in this case, the fifth
DC power supply E5 is connected to other DC power supplies E1, E2, E3, E
It is needless to say that the voltage is set to be higher than that of No. 4.

Embodiment 17 FIG. Next, a seventeenth embodiment of the present invention will be described with reference to FIG. In this embodiment, the fourteenth, twenty-fourth, twenty-fifth, and
This mainly describes the twenty-sixth invention. FIG. 52 shows a main circuit diagram according to the seventeenth embodiment.
The second DC power source E2, the sixth DC power source E6, the seventh DC power source E7, and the eighth DC power source E8 are connected in series,
Further, a third switching element 501 and a diode 502
Is connected to a connection point between the second DC power supply E2 and the sixth DC power supply E6, and the other end is connected to a connection point between the reactor 203 and the diode 202. The fourth switching element 514 and the diode 5
15 is connected to the connection point between the sixth DC power supply E6 and the seventh DC power supply E7, and the other end is connected to the connection point between the reactor 203 and the diode 202. Also, one end of the first switching element 201 is
It is connected to a connection point between the seventh DC power supply E7 and the eighth DC power supply E8, and the other end is connected to a connection point between the reactor 203 and the diode 202. Further, one end of a series body of the sixth switching element 526 and the resistor 529 is connected to one end of the eighth DC power supply E8, and the other end is connected to the electrode 1 (or the workpiece 2). FIG. 52
527 is a diode.

Therefore, in the thirteenth, fourteenth and sixteenth embodiments, the first, second, third and fifth DC power supplies E
1, E2, E3, E5 and the discharge voltage are expressed by E
5>E1> E3 ≧ discharge voltage ≧ E2, the voltage of the sixth DC power supply E6 is E3-E2, the voltage of the seventh DC power supply E7 is E1-E6-E2, and the eighth DC power supply E8 Can be E5-E7-E6-E2 = E5-E1, and specifically, each DC voltage is 20-30 volts for E2, 5-15 volts for E6, 40-60 volts for E7,
E8 is about 70 to 230 volts, and a low voltage can be used as each DC power supply, and the power supply can be used effectively.

In this embodiment, when it is desired to perform the operation of the thirteenth embodiment, the fourth switching element 514 and the sixth switching element 526 are turned off, and the first switching element 201 and the first switching element 201 are turned off. The ON / OFF control of the third switching element 501 may be performed in the same manner as in the thirteenth embodiment. If the operation of the fourteenth embodiment is to be performed, the sixth switching element 526 is turned off. , The first switching element 201, the third switching element 501, and the fourth switching element 514
May be controlled in the same manner as in the fourteenth embodiment, and when the operation of the sixteenth embodiment is desired to be performed, the fourth switching element 514 is turned off.
The ON / OFF control of the first switching element 201, the third switching element 501, and the sixth switching element 526 may be performed in the same manner as in the sixteenth embodiment, and the detailed operation is easier than the operation described above. Therefore, the description is omitted.

Embodiment 18 FIG. Next, an eighteenth embodiment of the present invention will be described with reference to FIG. FIG. 53 shows a main circuit diagram according to the eighteenth embodiment. This embodiment is a combination of the fourteenth embodiment and the sixteenth embodiment. That is, the first embodiment is different from the sixteenth embodiment in that
The series circuit of the third DC power supply E3, the fourth switching element 514, and the diode 515 in the fourth embodiment includes:
It is connected to the first diode 202 in parallel.
Since the operation can be easily understood from the operation explanation already described, the explanation is omitted.

Embodiment 19 FIG. In the thirteenth to eighteenth embodiments, the switching element has been described as a transistor. However, the switching element may be any element that can be electrically turned on and off.
The same effect can be obtained even with a switching element such as T. The control circuits of the eighth to seventeenth embodiments include a comparator, a timer circuit, a flip-flop, each command value, A
Although the ND circuit and inverter are configured in analog,
The same effect can be obtained even if a digital configuration is used by using an SP (digital signal processor) or a microcomputer.

[0197]

[0198]

As described above , according to the first invention,
If, because the circuit for superimposing compensate the current ripple configured by the on-off control of the resistive circuit, the effect of ripple less control is easy discharge machining device is obtained.

[0199] According to the second invention, a circuit for superimposing compensate the current ripple since it is configured by a semiconductor amplifier circuit,
There is an effect that an electric discharge machine having less ripple and a simple circuit configuration as compared with the first invention can be obtained.

According to the third and fourth aspects of the present invention, the switching power supply is constituted by an energy storage circuit comprising a switching element, a reactor, and a diode .
As compared with the first and second aspects, there is an effect that an electric discharge machining power source having higher power source efficiency can be obtained.

According to the fifth and sixth aspects of the invention, the current value of the discharge current pulse from the switching power supply is controlled together with the subtraction command for subtracting a certain amount from the current value command signal, and the subtraction command and the switching power supply are controlled. Since the current value for compensating for the ripple is supplied from the superimposing circuit, the current value of the switching power supply can be set so as not to exceed the command value. effective.

According to the seventh aspect of the present invention, the circuit for reducing the excess current when the current value of the discharge current pulse from the switching power supply exceeds the command signal, and the insufficient current component when the current value is equal to or less than the command value. Since the superimposing circuit is provided, there is an effect that the machining surface roughness is not deteriorated and an electric discharge machining apparatus with less ripple can be obtained.

According to the eighth and ninth aspects, the switching of the switching power supply is controlled by a signal obtained by adding the current value command signal of the discharge current pulse and the signal of the ripple setting means. There is no need for a circuit for compensating and superimposing ripples as in the seventh invention, and there is an effect that an electric discharge machining method and apparatus with little ripple can be obtained.

According to the tenth aspect , the frequency of the ripple setting means in the ninth aspect can be varied. For example, by increasing the frequency in the case of machining with a small current value, the discharge current with little ripple and no interruption can be obtained. Pulses are obtained, and there is an effect that an electric discharge machining apparatus capable of performing machining with good machining surface roughness can be obtained.

According to the eleventh aspect , even if noise occurs in the comparison circuit between the current command signal of the discharge current pulse and the actual current detection value, the switching control of the switching power supply can be performed reliably, and the ripple can be reduced. There is an effect that a small number of electric discharge machines can be obtained.

According to the twelfth aspect , two sets of switching power supplies are connected in parallel, and the switching of the switching power supplies is controlled by a signal obtained by shifting the phase of the signal of the ripple setting means by 180 degrees. This has the effect of obtaining an electric discharge machining apparatus capable of generating a discharge current pulse with a small number of pulses.

According to the thirteenth aspect , the switching is turned off for a predetermined time by the timer after the current value signal of the discharge current pulse matches the actual current detection signal. Since the command value is not exceeded, there is an effect that a machining surface roughness is not deteriorated and an electric discharge machining apparatus with little ripple is obtained.

According to the fourteenth and fifteenth aspects, the switching power supply is constituted by an energy storage circuit including a switching element, a reactor, and a diode, and the current that decreases when the switching of the switching power supply is off is reduced.
Since the second power supply having a voltage equal to or lower than the discharge voltage is supplied from the connection point between the reactor and the switching element through the third switching element, the discharge current pulse has less ripple and the power supply efficiency is high. There is an effect that a processing method and an apparatus can be obtained.

[0209] According to the sixteenth aspect , in addition to the fifteenth aspect , the driving of the third switching element is turned off when the detected current value of the reactor exceeds the overcurrent command value. Can be controlled to be equal to or less than the overcurrent command, and there is an effect that an electric discharge machining apparatus which has less ripple and does not deteriorate the machining surface roughness can be obtained.

According to the seventeenth and eighteenth aspects, the first
According to the fourth to sixteenth aspects of the present invention, a ripple is supplied from a power supply lower than the switching power supply and higher than the discharge voltage through the switching element from a connection point between the reactor and the switching element. The present invention has an effect that a current pulse can be obtained, and an electric discharge machining method and apparatus having less ripple and a good machining speed can be obtained.

[0211] According to the nineteenth aspect, since the switching of the fourth switching element performs the timer, 20th
According to the invention of the seventeenth to nineteenth aspects, the power supply voltage of the circuit for replenishing ripples is made variable, so that an optimal discharge current pulse with little ripple with respect to the current value command is obtained, and There is an effect that a good electric discharge machining device can be obtained.

According to the twenty-first aspect , the seventeenth through the second aspects
In the invention of No. 0 , when the current detection value of the reactor exceeds the overcurrent command value, the circuit for supplementing the ripple is controlled to be turned off, so that the current value of the discharge current pulse is always controlled to be equal to or less than the overcurrent command value. It is possible to obtain an electric discharge machining apparatus which has little ripple and does not deteriorate the machining surface roughness.

[0213] According to the invention of a 22, further to the fifteenth aspect, since there is provided in parallel circuit for applying a first voltage higher than the power supply with the machining gap, in addition to reduce the ripple, the discharge This has the effect of facilitating the occurrence of erosion and providing an electric discharge machining apparatus with high machining efficiency.

[0214] According to the invention of a 23, Aspect 22, when the current detection value of the reactor exceeds the over-current command value, since to control off the circuit to replenish ripple, discharge current The current value of the pulse can always be controlled to be equal to or less than the overcurrent command, the ripple is small, the generation of electric discharge is ensured, and there is an effect that an electric discharge machining apparatus which does not deteriorate the machining surface roughness can be obtained.

According to the twenty-fourth, twenty-fifth, and twenty-sixth inventions, the power supplies of the fourteenth to twenty-third inventions are constituted by a combination of a plurality of low-voltage power supplies. There is an effect that the device can be configured at low cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a current waveform diagram obtained by the first embodiment.

FIG. 3 is a current waveform diagram obtained by the first embodiment.

FIG. 4 is an operation timing chart showing the operation of the circuit of the first embodiment.

FIG. 5 is a current waveform diagram obtained by the first embodiment.

FIG. 6 is a circuit diagram showing a second embodiment of the present invention.

FIG. 7 is a circuit diagram showing a third embodiment of the present invention.

FIG. 8 is a rectangular current waveform diagram in the third embodiment.

FIG. 9 is a triangular wave current waveform diagram in the third embodiment.

FIG. 10 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 11 is a rectangular current waveform diagram in the fourth embodiment.

FIG. 12 is a triangular wave current waveform diagram in the fourth embodiment.

FIG. 13 is a triangular wave current waveform diagram in the fourth embodiment.

FIG. 14 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 15 is a circuit diagram showing a sixth embodiment of the present invention.

FIG. 16 is a circuit diagram showing a seventh embodiment of the present invention.

FIG. 17 is a current waveform diagram obtained by the fifth embodiment.

FIG. 18 is a current waveform diagram obtained by the sixth embodiment.

FIG. 19 is a current waveform diagram obtained by the seventh embodiment.

FIG. 20 is a circuit diagram showing an eighth embodiment of the present invention.

FIG. 21 is a waveform chart and a time chart for explaining the operation of the eighth embodiment.

FIG. 22 is a waveform chart for explaining a modification of the eighth embodiment.

FIG. 23 is a circuit diagram showing a ninth embodiment of the present invention.

FIG. 24 is Vf for explaining the operation of the ninth embodiment;
It is a characteristic diagram.

FIG. 25 is a waveform chart and a time chart for explaining the operation of the ninth embodiment.

FIG. 26 is a circuit diagram showing a tenth embodiment of the present invention.

FIG. 27 is a waveform chart and a time chart for explaining the operation of the tenth embodiment.

FIG. 28 is a circuit diagram showing an eleventh embodiment of the present invention.

FIG. 29 is a waveform chart for explaining the operation of the eleventh embodiment.

FIG. 30 is a waveform chart for explaining the operation of the eleventh embodiment.

FIG. 31 is a circuit diagram showing a twelfth embodiment of the present invention.

FIG. 32 is a waveform chart and a time chart for explaining the operation of the twelfth embodiment.

FIG. 33 is a main circuit diagram showing a thirteenth embodiment of the present invention.

FIG. 34 is a circuit diagram showing a control circuit according to a thirteenth embodiment of the present invention.

FIG. 35 is a circuit diagram showing an example of a timer circuit according to a thirteenth embodiment of the present invention.

FIG. 36 is a circuit diagram showing another example of the timer circuit according to the thirteenth embodiment of the present invention.

FIG. 37 is a time chart for explaining the operation of the timer circuit according to the thirteenth embodiment of the present invention.

FIG. 38 is a waveform chart and a time chart for explaining a main operation according to a thirteenth embodiment of the present invention.

FIG. 39 is a waveform chart and a time chart for explaining the operation at the time of short-circuit between poles according to the thirteenth embodiment of the present invention.

FIG. 40 is a circuit diagram showing another example of the control circuit according to the thirteenth embodiment of the present invention.

FIG. 41 is a waveform chart for explaining an actual operation according to a thirteenth embodiment of the present invention.

FIG. 42 is a waveform chart for explaining an actual operation according to a thirteenth embodiment of the present invention.

FIG. 43 is a main circuit diagram showing a fourteenth embodiment of the present invention.

FIG. 44 is a circuit diagram showing a control circuit according to a fourteenth embodiment of the present invention.

FIG. 45 is a waveform chart and a time chart for explaining a main operation according to a fourteenth embodiment of the present invention.

FIG. 46 is a main circuit diagram showing a fifteenth embodiment of the present invention.

FIG. 47 is a circuit diagram showing a control circuit according to a fifteenth embodiment of the present invention.

FIG. 48 is a waveform chart and a time chart for explaining a main operation according to the fifteenth embodiment of the present invention.

FIG. 49 is a main circuit diagram showing a sixteenth embodiment of the present invention.

FIG. 50 is a circuit diagram showing a control circuit according to a sixteenth embodiment of the present invention.

FIG. 51 is a waveform chart and a time chart for explaining a main operation according to a sixteenth embodiment of the present invention.

FIG. 52 is a main circuit diagram showing a seventeenth embodiment of the present invention.

FIG. 53 is a main circuit diagram showing an eighteenth embodiment of the present invention.

FIG. 54 is a circuit diagram showing a first conventional example.

FIG. 55 is a current waveform diagram generated by the circuit of FIG. 33.

FIG. 56 is a current waveform diagram for explaining a problem of the first conventional example.

FIG. 57 is a current waveform diagram for describing a problem of the first conventional example.

FIG. 58 is a circuit diagram showing a second conventional example.

FIG. 59 is a current waveform diagram generated by the circuit of FIG. 58.

FIG. 60 is a circuit diagram showing a third conventional example.

FIG. 61 is a current waveform diagram generated by the circuit diagram of FIG. 60;

FIG. 62 is a diagram showing a current waveform generated by the circuit diagram of FIG. 60;

FIG. 63 is a circuit diagram showing a fourth conventional example.

FIG. 64 is a current characteristic diagram of the semiconductor amplifier used in the circuit of FIG. 63;

[Explanation of symbols]

Reference Signs List 1 electrode 2 workpiece 4 first switching element 5 power supply 6 diode 7 current detector 100a to 100c second switching element 101a to 100c resistor 102 current command value signal setting device 103 current command value signal generator 105 signal conversion Device 107 first signal adder / subtracter 109 logic circuit 113 second signal adder / subtractor 114 A / D converter E1 to E8 first to eighth power supply H1 discharge signal H2 current increase signal H3 no-load voltage signal H4 high voltage pulse signal I1 Current detection value S1 Current command value 201, 211, 501, 514, 521, 526 Switching element 504 First comparator 505 Second comparator 506 DC power supply 507 Overcurrent command value 508 First flip-flop 509 Inverter 510, 511 , 518, 519, 523 , 524 A
ND circuit 517 OR circuit 512 Timer circuit 200 Constant current supply unit 202, 212, 204, 502, 515, 522, 5
27, Diode 203 Reactor 205 Current Detector 210 Output Current Interruption Unit 1 Electrode 2 Workpiece

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshihide Kanehara 5-1-1, Yadaminami, Higashi-ku, Nagoya-shi Nagoya Works, Mitsubishi Electric Corporation (56) References JP-A-62-44317 (JP, A) JP-A-55-79679 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23H 1/02 B23H 7/14

Claims (26)

(57) [Claims] 1. A power supply device of an electric discharge machine for melting and removing a workpiece by supplying a pulsed electric power between an electrode provided in a machining fluid and the workpiece, wherein machining energy is supplied to a machining gap. Power supply, first
The first switching element in which a switching element and a resistor are connected in series
A set of a circuit in which a second switching element and a resistor are connected in series; The first switching element and the resistor of the processing circuit of (1) are connected in parallel to the resistor or a part of the resistor, and are configured to supply the current to the processing gap by overlapping with the current from the first processing circuit. A second processing circuit, a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to a processing gap, the current command value signal or a part thereof and the current detection First signal addition / subtraction means for calculating and outputting the difference from the output from the means; and a first signal output to a first switching element of the first processing circuit in accordance with an output of the first signal addition / subtraction means.
Control means; second signal addition / subtraction means for calculating and outputting the difference between the current command value signal and the output of the current detection means; and the second processing circuit in response to the output of the second signal addition / subtraction means. And a second control means for outputting a signal to one or more of the second switching elements. 2. A power supply device for an electric discharge machine for melting and removing a workpiece by supplying pulsed electric power between an electrode provided in the machining fluid and the workpiece. A first processing circuit in which a power supply, a first switching element, and a resistor are connected in series; a current detection means for detecting a current flowing in the first processing circuit; and a set of circuits to which a semiconductor amplifier is connected Alternatively, a plurality of sets are connected in parallel to the first switching element and the resistor of the first processing circuit or a part of the resistor, and the processing is performed by overlapping with the current from the first processing circuit. A second processing circuit configured to supply a current to the gap, means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to the processing gap, and the current command value signal or A first signal addition / subtraction unit for calculating and outputting a difference between a part of the signal of the first circuit and the output from the current detection unit; and a first processing circuit of the first processing circuit according to an output of the first signal addition / subtraction unit. First to output a signal to the switching element
Control means, a second signal addition / subtraction means for calculating and outputting a difference between the current command value signal and the output of the current detection means, and a second processing circuit of the second processing circuit according to an output of the second signal addition / subtraction means. And a second control means for outputting a signal to the semiconductor amplifier. 3. A power supply device for an electric discharge machine for melting and removing a workpiece by supplying pulsed electric power between an electrode provided in the machining fluid and the workpiece. A first switching element, a reactor, and a first power supply for intermittently supplying and storing electric energy from the power supply.
And an electric energy storage circuit configured by connecting the diodes in series, the output current from the electric energy storage circuit is connected to be supplied to the machining gap, and the output current is supplied to the machining gap. A third switching element for supplying pulses, and a second diode connected to return the residual current generated in the machining gap to the electric energy storage circuit when the third switching element is turned off. A first processing circuit comprising: a first processing circuit, a current detection means for detecting a current flowing through the first processing circuit, and a set or a plurality of circuits in which a second switching element and a resistor are connected in series. A set is connected in parallel to the electrical energy storage circuit of the first processing circuit, and superimposes a current from the first processing circuit to supply a current to the processing gap. A second processing circuit configured to supply the current command value signal corresponding to the waveform shape of the current pulse to be supplied to the processing gap; and a current command value signal or a part thereof. First signal addition / subtraction means for calculating and outputting a difference between a signal and an output from the current detection means; and a signal to a first switching element of the first processing circuit in response to an output of the first signal addition / subtraction means. Output the first
Control means, a second signal addition / subtraction means for calculating and outputting a difference between the current command value signal and the output of the current detection means, and a second processing circuit of the second processing circuit according to an output of the second signal addition / subtraction means. And a second control means for outputting a signal to at least one second switching element. A power supply device for an electric discharge machine, comprising: 4. A power supply device for an electric discharge machine for melting and removing a workpiece by supplying pulsed electric power between an electrode provided in the machining fluid and the workpiece. A first switching element, a reactor, and a first power supply for intermittently supplying and storing electric energy from the power supply.
And an electric energy storage circuit configured by connecting the diodes in series, and an output current from the electric energy storage circuit is connected to be supplied to the machining gap. And a second diode connected to return the residual current generated in the machining gap to the electric energy storage circuit when the third switching element is turned off. A first processing circuit comprising: a first processing circuit, a current detection means for detecting a current flowing through the first processing circuit, and a set or a plurality of circuits connected to a semiconductor amplifier, the first processing circuit comprising: The electric energy storage circuit of the circuit is connected in parallel with the electric energy storage circuit, and is configured to be able to supply a current to the machining gap by overlapping with the current from the first machining circuit. A second processing circuit, a means for setting a current command value signal corresponding to a waveform shape of a current pulse to be supplied to the processing gap, and a signal from the current detection means or a part of the current command value signal. First signal addition / subtraction means for calculating and outputting the difference from the output; first control means for outputting a signal to a first switching element in accordance with the output of the first signal addition / subtraction means; Signal addition / subtraction means for calculating and outputting the difference between the signal and the output of the current detection means; and a second signal output to the semiconductor amplifier of the second processing circuit in accordance with the output of the second signal addition / subtraction means. A power supply device for an electric discharge machine, comprising: a control unit. 5. A power supply device of an electric discharge machine for melting and removing a workpiece by supplying pulsed power between an electrode provided in a machining fluid and the workpiece, wherein a current pulse is supplied to a machining gap. A first current source for supplying; a current detecting means for detecting a current supplied to the machining gap by the first current source; a first current source connected in parallel to the first current source; A second current source configured to be able to supply current to the machining gap by superimposing the current from the second current source and having a faster response speed of the output current than the first current source; and to supply the current to the machining gap. Means for setting a current command value signal corresponding to the waveform shape of the current pulse; subtracting means for subtracting a certain amount from the current command value signal; and outputting the output of the subtracting means to a current command to the first current source. First control means for outputting as a value, And a second control means for outputting a difference between the current command value signal and an output from the current detection means as a current command of the second current source. . 6. A power supply device of an electric discharge machine for melting and removing a workpiece by supplying pulsed power between an electrode provided in a machining fluid and the workpiece, wherein a current pulse is supplied to a machining gap. A first current source for supplying; a current detecting means for detecting a current supplied to the machining gap by the first current source; a first current source connected in parallel to the first current source; A second current source configured to be able to supply current to the machining gap by superimposing the current from the second current source and having a faster response speed of the output current than the first current source; and to supply the current to the machining gap. Means for setting a current command value signal corresponding to the waveform shape of the current pulse; multiplying means for multiplying the current command value signal by a value less than 1 and greater than 0; an output of the multiplying means to the first current source Control means for outputting as a current command value of And a second control means for outputting a difference between the current command value signal and the output from the current detection means as a current command of a second current source, comprising: a power supply for an electric discharge machine. apparatus. 7. A power supply device of an electric discharge machine for melting and removing a workpiece by supplying pulsed power between an electrode provided in a machining fluid and the workpiece, wherein a current pulse is supplied to a machining gap. A first current source for supplying; a current detecting means for detecting a current supplied to the machining gap by the first current source; a first current source connected in parallel to the first current source; A second current source configured to be able to supply a current to the machining gap by superimposing the current from the second current source, the second current source having a faster response speed of the output current than the first current source; A third current source that is connected in parallel and can supply current in the opposite direction to the current supply direction of the second current source, and has a faster response speed of the output current than the first current source; Current corresponding to the shape of the current pulse to be supplied to the gap Means for setting a command value signal; first control means for outputting the current command value signal to the first current source as a current command value to the first current source; A second control means for outputting a positive difference detected by the current detection means of the current source as a current command for the second current source; and a current command value signal and a current detector for the first current source. And a third control means for outputting a negative difference detected as a current command of a third current source, the power supply device for an electric discharge machine. 8. A processing apparatus comprising: a constant current supply unit having at least a first switching element; and an output current intermittent section having a second switching element, wherein processing power is supplied between an electrode provided in a processing liquid and a workpiece. In a method of controlling a power supply for an electric discharge machine to be supplied, an output current level and an output current ripple of the constant current supply unit are set, and a value obtained by adding the set output current level and the output current ripple is determined. The output current command signal of the current supply unit, and comparing the output current command signal with the output current of the constant current supply unit, and controlling the switching element of the constant current supply unit based on the comparison result. Control method of power supply for electric discharge machine. 9. A processing apparatus comprising: a constant current supply unit having at least a first switching element; and an output current intermittent section having a second switching element, wherein processing power is supplied between an electrode provided in a processing liquid and a workpiece. Detecting means for detecting an output current of the constant current supply unit, output current level setting means for commanding an output current level of the constant current supply unit, and output current ripple of the constant current supply unit Ripple current setting means for instructing the output current level setting means, and comparing the set value obtained by adding the set value of the ripple current setting means to the set value of the output current level setting means with the detection value of the detection means. Means for controlling on / off of the first switching element of the constant current supply unit according to the comparison. Wherein said ripple current setting means, according to claim 9, characterized in that it comprises a modulation means for modulating the set signal frequency of the ripple current set value according to the set value of the output current level setting means Power supply unit for electric discharge machine. 11. A processing apparatus comprising: a constant current supply unit having at least a first switching element; and an output current intermittent unit having a second switching element, wherein processing power is supplied between an electrode provided in a processing liquid and a workpiece. Detecting means for detecting the output current of the constant current supply unit, output current level setting means for commanding the output current of the constant current supply unit, and ripple of the output current of the constant current supply unit A ripple current setting means for instructing a current; a means for outputting a synchronization signal synchronized with a setting signal of a ripple current setting value of the ripple current setting means; and a setting value of the output current level setting means. Comparing means for comparing the set value obtained by adding the set value with the detected value of the detecting means; inputting the output of the comparing means and the synchronization signal;
A power supply device for an electric discharge machine, comprising: gate means for removing noise accompanying the opening and closing of the switching element; and means for turning on and off the first switching element in accordance with the output of the gate means. . 12. A constant current supply unit having at least a first switching element, and an output current interrupting unit having a second switching element, wherein processing power is supplied between an electrode provided in a processing liquid and a workpiece. In the power supply device for an electric discharge machine to be supplied, a first constant current supply unit, a second constant current supply unit, first detection means for detecting an output current of the first constant current supply unit, Second detection means for detecting the output current of the constant current supply section, output current level setting means for instructing the output current levels of the first and second constant current supply sections, and First to command output current ripple
Ripple current setting means, second ripple current setting means for instructing a setting value 180 degrees out of phase with the setting value of the first ripple current setting means, and the first and second output current level setting means First comparing means for comparing a set value obtained by adding the set value of the first ripple current setting means to the set value of the first ripple current and the detected value of the first detecting means; and the first and second output current levels Second comparing means for comparing a set value obtained by adding a set value of the second ripple current setting means to a set value of the setting means and a detected value of the second detecting means; and the first and second comparisons A power supply device for an electric discharge machine, comprising: means for controlling on / off of the first switching element of the first and second constant current supply units according to the comparison of the means. 13. A processing apparatus comprising: a constant current supply unit having at least a first switching element; and an output current intermittent section having a second switching element, wherein processing power is supplied between an electrode provided in a processing liquid and a workpiece. Detecting means for detecting an output current of the constant current supply unit, output current level setting means for instructing an output current level of the constant current supply unit, and setting of the output current level setting means. Means for comparing a value with a value detected by the detecting means, and outputting a signal for turning off the first switching element of the constant current supply section based on the result of the comparison; A means for outputting a signal for turning off the first switching element of the constant current supply unit after the means outputs a signal for turning off the first switching element of the constant current supply unit, and outputting a signal for turning on the first switching element of the constant current supply unit after a predetermined time has elapsed. Means and, power supply device for an electrical discharge machine, characterized by comprising means for the first on-off control of the switching element based on the output of the timer means. 14. A constant current supply unit comprising a first DC power supply, a first switching element, a diode, and a reactor, and supplies processing power between an electrode provided in a processing liquid and a workpiece. In the control method of the power supply for the electric discharge machine, by switching the first switching element at an arbitrary cycle, a current corresponding to the current command value signal is supplied from the first DC power supply to the machining gap. A control of a power supply for an electric discharge machine, wherein a current for suppressing a decrease in an output current generated when the first switching element is turned off during supply is supplemented from a connection point between the first switching element and the reactor. Method. 15. A first DC power supply, a first switching element connected to one of the first DC power supplies,
And a diode having one end connected to the other electrode of the first DC power supply and the other end connected to a connection point between the first switching element and the reactor. A power supply device for an electric discharge machine, comprising: a constant current supply unit having a constant current supply unit; and an output current intermittent unit having a second switching element, and supplying machining power between an electrode provided in a machining fluid and a workpiece. A second direct-current power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the gap, a third switching element, and a diode in series with the diode of the constant current supply unit. A power supply device for an electric discharge machine, which is connected in parallel. 16. A first comparing means for comparing a current command value with a detected current value of a reactor, a second comparing means for comparing an overcurrent command value with a detected current value of the reactor,
Timer means having an input terminal connected to the output of the first comparing means, a reset input terminal being connected to the output of the second comparing means, and a set input terminal being connected to an inverted signal of the output of the first comparing means. A first state storage means for controlling a first switching element by a product of an output of the timer means, an output of the first state storage means, and a discharge signal; The third switching element is controlled by the product of the output of the first switching element and the discharge signal, and the second switching element is controlled by the discharge signal. When the current detection value of the reactor exceeds the current command value, the first switching element is controlled. as well as the set time off timer means, when the current detection value of the reactor exceeds the over-current command value claims, characterized in that the third switching element is also turned off 5 power supply device for an electrical discharge machine according to. 17. A processing apparatus comprising: a first direct-current power supply, a first switching element, a constant current supply unit including a diode and a reactor, and supplying processing power between an electrode provided in a processing liquid and a workpiece. In the control method of the power supply for the electric discharge machine, when controlling the output current at a constant current level,
A voltage higher than the discharge voltage and lower than the voltage supplied from the first DC power supply is supplied to the machining gap from the third DC power supply, and at this time, the first switching element is turned off. Controlling the current from the third DC power supply by switching a switching element that is separate from the first switching element at an arbitrary cycle. 18. A first DC power supply, a first switching element connected to one of the first DC power supplies,
And a diode having one end connected to the other electrode of the first DC power supply and the other end connected to a connection point between the first switching element and the reactor. A power supply device for an electric discharge machine, comprising: a constant current supply unit having a constant current supply unit; and an output current intermittent unit having a second switching element, and supplying machining power between an electrode provided in a machining fluid and a workpiece. A second direct-current power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the gap, a third switching element, and a diode in series with the diode of the constant current supply unit. A third DC power supply connected in parallel and having a voltage higher than the discharge voltage and lower than the voltage supplied from the first DC power supply to the machining gap; A switching element, a series of a diode, the power supply device for an electrical discharge machine, characterized in that to the constant current supply of the diode connected in parallel. 19. A first comparing means for comparing a current command value with a detected current value of a reactor, a second comparing means for comparing an overcurrent command value with a detected current value of the reactor,
Timer means having an input terminal connected to the output of the first comparing means, a reset input terminal being connected to the output of the second comparing means, and a set input terminal being connected to an inverted signal of the output of the first comparing means. Controlling the fourth switching element based on the sum of the output of the timer means and the current increase signal and the product of the output of the first state storage means and the discharge signal. Controlling the first switching element by the product of the output of the timer means, the current increase signal and the discharge signal, and controlling the third switching element by the product of the output of the first state storage means and the discharge signal The second switching element is controlled by the discharge signal, and when the current detection value of the reactor exceeds the current command value, the fourth switching element is set to the time set by the timer means. As well as the off, when the current detection value of the reactor exceeds the over-current command value claims, characterized in that the third and fourth switching elements also off
19. The power supply device for an electric discharge machine according to 18 . 20. A first DC power supply, a first switching element connected to one of the first DC power supplies,
And a diode having one end connected to the other electrode of the first DC power supply and the other end connected to a connection point between the first switching element and the reactor. A power supply device for an electric discharge machine, comprising: a constant current supply unit having a constant current supply unit; and an output current intermittent unit having a second switching element, and supplying machining power between an electrode provided in a machining fluid and a workpiece. A second direct-current power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the gap, a third switching element, and a diode in series with the diode of the constant current supply unit. A series of a fourth DC power supply, a fifth switching element, and a diode connected in parallel and capable of changing a voltage is connected to a diode of the constant current supply unit. Power supply device for an electrical discharge machine being characterized in that connected in parallel to the. 21. A first comparing means for comparing a current command value with a detected current value of a reactor, a second comparing means for comparing an overcurrent command value with a detected current value of the reactor,
Timer means having an input terminal connected to the output of the first comparing means, a reset input terminal being connected to the output of the second comparing means, and a set input terminal being connected to an inverted signal of the output of the first comparing means. A first state storage means for controlling a fifth switching element by a product of an output of the timer means, an output of the first state storage means, and a discharge signal, and a no-load voltage signal and a discharge signal. And the first
And the third switching element is controlled by the product of the output of the first state storage means and the discharge signal, and the second switching element is controlled by the discharge signal. When the detected value exceeds the current command value, the fifth switching element is turned off for the time set in the timer means, and when the current detection value of the reactor exceeds the overcurrent command value, the third and fifth switching elements are turned off. The power supply device for an electric discharge machine according to claim 20 , wherein the element is also turned off. 22. A first DC power supply, a first switching element connected to one of the first DC power supplies,
And a diode having one end connected to the other electrode of the first DC power supply and the other end connected to a connection point between the first switching element and the reactor. A power supply device for an electric discharge machine, comprising: a constant current supply unit having a constant current supply unit; and an output current intermittent unit having a second switching element, and supplying machining power between an electrode provided in a machining fluid and a workpiece. A second direct-current power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the gap, a third switching element, and a diode in series with the diode of the constant current supply unit. A fifth DC power supply connected in parallel and having a voltage capable of supplying a voltage higher than the voltage supplied from the first DC power supply to the machining gap;
A power supply device for an electric discharge machine, wherein a series body of a switching element and a resistor is connected in parallel to a machining gap. 23. A first comparing means for comparing a current command value with a detected current value of a reactor, a second comparing means for comparing an overcurrent command value with a detected current value of the reactor,
Timer means having an input terminal connected to the output of the first comparing means, a reset input terminal being connected to the output of the second comparing means, and a set input terminal being connected to an inverted signal of the output of the first comparing means. A first state storage means for controlling a first switching element by a product of an output of the timer means, an output of the first state storage means, and a discharge signal; Controlling the third switching element by the product of the output of the first switching element and the discharge signal, controlling the second switching element by the discharge signal, and furthermore, the first switching element when the current detection value of the reactor exceeds the current command value. Is turned off for a time set in the timer means, and when the detected current value of the reactor exceeds the overcurrent command value, the third switching element is also turned off, and the high-voltage pulse signal is turned off. Power supply device for an electrical discharge machine according to claim 22, wherein turning on the sixth switching element by the product of the discharge signal. 24. A first DC power supply, a first switching element connected to one electrode of the first DC power supply, a reactor connected in series with the first switching element, and one end connected to the first DC power supply. A constant current supply unit having a diode connected to the other electrode of the first DC power supply and having the other end connected to a connection point between the first switching element and the reactor, and an output current having a second switching element A power supply device for an electric discharge machine, comprising an intermittent portion and supplying machining power between an electrode provided in the machining fluid and the workpiece, wherein the first DC power supply is a plurality of DC power supplies having a predetermined voltage. Are connected in series, and one of the plurality of DC power supplies is a second DC power supply having a voltage capable of supplying a voltage substantially equal to or lower than the discharge voltage to the machining gap, and One end of a series body of a third switching element and a diode is connected to a connection point between the second DC power supply and another DC power supply, and the other end is a connection point between the first switching element and the reactor. A power supply device for an electric discharge machine, wherein the power supply device is connected to a power supply. 25. A voltage capable of supplying a voltage higher than the discharge voltage to the machining gap and lower than the voltage supplied from the first DC power supply together with the second DC power supply to another one of the plurality of DC power supplies. And connecting one end of a series body of a fourth switching element and a diode to a connection point between the sixth DC power supply and another DC power supply other than the second DC power supply. 25. The power supply device for an electric discharge machine according to claim 24 , wherein the power supply device is connected, and the other end is connected to a connection point between the first switching element and the reactor. 26. An eighth DC power supply is connected in series to the first DC power supply, and one end of a series body of a sixth switching element and a resistor is connected to one end of the eighth DC power supply. , power supply device for an electrical discharge machine according to claim 24 or claim 25, characterized in that connecting the other end to the electrode or the workpiece.