SU1148573A3 - Device for controlling static frequency converter - Google Patents

Abstract

1. A CONTROL DEVICE FOR STATIC FREQUENCY CONVERTER with an inverter, an inverter and an inductance coil with a diversion from the midpoint containing the master oscillator, pulse distributor, control pulse generator, amplifiers of the main thyristors and thyristors with separation pulse generators, pulse generators, pulse amplifiers of the main thyristors and quench thyristors with pulse transformers, pulse generators, pulse amplifiers of the main thyristors and thyristors with pulse transformers, pulse generators, pulse amplifiers of the main thyristors and thyristors with positioning transformers, pulse generators, pulse amplifiers of the main thyristors and thyristors with positioning transformers, pulse generators, pulse amplifiers of the main thyristors and thyristors with positioning transformers, pulse control, pulse amplifiers of the main thyristors and thyristors with sectional pulses protection, the start-up and shut-down circuit of the statistical converter, characterized in that, in order to increase the reliability of operation, the first input of the central node is protected It is connected to the inserted internal short circuit detector via an inverter, the second input is connected to the output of the inserted protection unit when the voltage deviates from the permissible limits, the third input to the output of the external short circuit protection unit, a quarter to the output of the protection unit against the constant component, but. the output of the central protection node is connected to the first input of the pulse distributor, and with the input power supply circuit and with the input short circuit, which is connected between the center point of the inductor and the common point of the output of the rectifier and input, the inverter, and the input circuit of the starting and switching off static converter with the first output of the pulse distributor, the output of this circuit is connected to the inserted switch of the converter and the second input of the pulse distributor. The third input of the pulse distributor (/) is connected to the output of the master (Generator, the fourth input of the pulse distributor is connected to the output of the control pulse generator, and the other outputs of the pulse distributor are connected to the pulse amplifiers thyristor, the quench level, and the main pulse amplifiers of the thyristors and with the inputs-blockers of the amplifiers of the pulses of the main thyristors, ate 2. Device pop. 1, distinguished: 00, because the distributor of pulses contains two frequency dividers, the midpoint of which is connected to the input and tegriruyuschey circuit, the output of which is connected to the input of the Schmitt trigger, the second input of which is connected to a potentiometer and the outputs of the flip-flop and a second frequency divider connected to the input of first and second logical AND gates whose outputs are connected to the input of first and second differentiating circuits and two input yn

Description

The circuits whose outputs are connected to the inputs of the third and fourth differentiating circuits, the outputs of each of the differentiating circuits are connected to the inputs of the instability circuits, the outputs of which are the second output of the pulse distributor and connected to the inputs of the first pulse amplifiers that are connected to the primary windings of the first four separation circuits the thyristor pulse transformers are quenched, the third and fourth AND logic circuits, whose outputs are the third output of the pulse distributor, are connected of the two inputs to the outputs

the first logic circuits And, and the outputs of the third and fourth logic circuits

And they are connected via pulse amplifiers to the primary windings of the other four isolation pulse transformers of the main inverter thyristors, a trigger whose first input is connected to the start and stop circuit output, a second trigger input is connected to the output of the central protection node, and the trigger output is connected pulses of the main thyristors of the inverter and is the fourth output of the pulse limiter.

The invention relates to static frequency converter control systems with a DC link, which convert the variable frequency electrical energy of a primary source into a predetermined frequency electrical energy to power the heating circuits of railway passenger cars, as well as to provide electrical energy to some auxiliary units, such as battery charging, driving. engines of air conditioning equipment and the like, which are part of the equipment for electric heating of trains.

Known static frequency converters are used for electric heating of passenger trains in which electronic protection of the inverter is provided.

The disadvantages of such converters are design complexity and high cost.

The closest to the proposed technical entity is a frequency converter control unit comprising sequentially connected to each other via a coil of inductance, a rectifier and an inverter, main thyristors and quenching thyristors, protective circuits, and also a control unit including a master oscillator, a control oscillator pulses, amplifiers of the main thyristors and quenching thyristors with separation pulse transformers at the output, the central protection node and the start-up circuit Transducer Switches

However, the known device is characterized by insufficient reliability of operation.

The purpose of the invention is to increase the reliability of work.

The goal is achieved by the fact that in a control device with a top; a driver, an inverter and an inductance with a tap from the midpoint containing a master oscillator, a pulse distributor, a generator of control impulses, main thyristor and thyristor pulse amplifiers with output pulse transformers, a central node protection circuit, start and stop the static converter, the first input of the central node of the protection is connected to the internal short circuit detector through the inverter, the second input - with the output entered. € Loka protection when the voltage deviates from permissible limits, the third - with the output from the external short circuit, the fourth with the output of the protection unit from the constant component, and with the first input of the pulse distributor, with the input power supply circuit and with the input short-circuit, which is connected between the middle point of the inductor and the common point of the output of the rectifier and the inverter input, and the input of the start and trip circuit The static converter is connected to the first output of the pulse distributor, the output of this circuit is connected to the input switch of the converter and the second input of the pulse distributor, the third input of the last is connected to the output of the master oscillator, the fourth input is connected to the output of the control pulse generator, and the other pulse distributor it is connected respectively to the amplifiers of pulses of the thyristor, from the amplifiers of the pulses of the main thyristors, and with the inputs of blocking the amplifiers of the pulses of the main thyristors oops. In addition, the pulse distributor contains two frequency dividers, the midpoint of which is connected to the input of the integrating circuit, the output of which is connected to the Schmitt trigger input, the second input of which is connected to the potentiometer, and the outputs of the trigger and the second frequency divider are connected to the input of the first and The second logic circuits AND, 9INDITIONS of which are connected to the input of the first and second differentiating circuits and the inputs of two inverse circuits, the outputs of which are connected to the inputs of the third and fourth differentiating circuits, the outputs of each of the differentials The connecting circuits are connected to the inputs of the instability circuits, the outputs of which are the second output of the pulse distributor and connected to the inputs of the first four pulse amplifiers, which are connected to the primary windings of the first four separation pulse thyristor transformers, the third and fourth logic circuits AND, the outputs of which are third the output of the pulse distributor connected by two inputs to the outputs of the first logic circuits And, and the outputs of the third and fourth logic circuits 73 And connected through amplification whether there are pulses with primary windings d) of the four separating pulse transformers of the main thyristors of the inverter, the trigger, the first input of which is connected to the output of the start and stop circuit, the second input of the trigger is connected to the output of the central protection node, and the output of the trigger of the main thyristors and is the fourth output of the pulse distributor. FIG. Figure 1 shows a block diagram of a static frequency converter with a constant input voltage of a DC inverter; FIG. 2 is a schematic diagram of an inverter; Fig. 3 is a block diagram of the electronic circuit of the control and control; in fig. 4 is a block diagram of a static converter control device; in fig. 5 pulse diagram. A static frequency converter (Fig. 1) with an intermediate DC circuit consists of a full-wave three-phase bridge diode rectifier 1, an inverter 2 with forced switching of thyristors, a power supply switch 3, a load switch 4, a current transformer 5, a protective current transformer 6, a transformer 7 voltage, block 8 of automation and control, filter inductance coil 9 with the removal from the midpoint, filter capacitor 10, protective short circuit 11, limiting the load current to power inductance 12, recovery diode 13, limiting resistor 14, buffer capacitor 15, unit 16 for detecting the change of polarity of the intermediate circuit voltage. The static frequency converter is powered by a synchronous generator of heating equipment that provides a three-phase variable frequency voltage system depending on the number of revolutions of the drive diesel engine of this generator, and the magnitude of the voltage is stabilized at a predetermined level. The voltage is applied by means of a switch 3. The output DC voltage in the rectifier of converter 1 has a constant value regardless of what the generator voltage is. An inductance-type filter — capacitance 9, 10 provides, in addition to continuous adjustment, also the disconnection of the inverter in the event of failure in the system. The exclusion of overvoltage of the charge of the filtering capacitor is provided by a protection unit formed by diode 13 and RC elements 14 and 15. In the event of a failure in the inverter or in the load, short connector 11 is activated, which relieves the power supply voltage at the inverter terminals the time is up to 4 ms, commanding de-energizing the generator and turning off the static frequency converter. An inverter, 2, is supplied with a constant voltage of direct current and provides at its output a single-phase alternating voltage of a rectangular shape of constant magnitude and constant frequency. The control and automation unit 8 provides, through its electronic control equipment, the pulses necessary to operate the inverter with the selected frequency; it receives voltage information from transformer 7 and output current information from transformer 6 for protection against voltage and from an external com- short circuit, as well as the command to change the polarity of the voltage in the intermediate DC circuit from unit 16 to protect against internal short circuits in the inverter. This unit provides the connection and disconnection of the converter by activating switches 3 and 4 during start-up or the required shutdown sequence with responsibly wi-off during shutdown due to a fault in the system. The output current of the inverter is measured by the current transformer 5. This inverter is implemented according to a variant with forced (artificial) switching, which is provided with auxiliary extinguishing thyristors and condensers of the blanking circuit. The suppression of the main thyristors 17-20 (Fig. 2), which are currently in the conducting state, is achieved by removing the current going 73 through the main thyristors, simultaneously with the supply of the blocking voltage to their terminals. The inverter load is connected to the middle points of the bridge, formed by the main thyristors 17, 20, 18, and 19. Let the thyristors 17 and 20 unlock simultaneously, which determines the load current to flow during this half period. At the point in time when the unlocking of the thyristors 17 and 20, the damping capacitors 21-24 are charged by means of the auxiliary thyristors 25-28, to which the control impulse comes from the valve. These capacitors are charged in oscillatory circuits, which form elements 17, 26, 29, 22 and 20, 27, 30 and 23. Suppressing capacitors 22 and 23 are prepared to extinguish the main thyristors 17 and 20, at the time of arrival of the command the auxiliary thyristors 25 and 28j due to the charge of the capacitors, an oscillatory process begins to stop the conductance of the main thyristors 17 and 20. The discharge currents of the capacitors are closed in the aforementioned circuits. During the switching process of the oscillating circuit, the load current peaks the discharge current is closed by diodes 31 and 32 connected in parallel with the thyristors and the direct voltage drop across the thyristors is applied as a block voltage to the terminals of the main thyristors 17 and 20 after the end of the switching period the main thyristors are unlocked 18 and 19 and simultaneously suppressing thyristors 25 and 28. During the other half period, the load is connected through the main thyristors 18 and 19, and at the same time the charge boiling capacitors with appropriate polarity in chains, analogous to those specified above. Thus, the operation of the quenching circuit is prepared for the purpose of controlled quenching of the main thyristors 18 and 19. With a reactive load, when the main thyristors 17 and 20 (18 and 19) are quenched, the reactive load current is received by regenerative diodes 31 and 32 (33 and 34), which pass an electric current during a time proportional to the power factor of the load. The electronic control circuit of the inverter (Fig. 3) contains two parts: informational and amplifying, and it switches its main thyristors with a forced frequency. The operating frequency of the inverter is set by a clock pulse generator 35, which produces square stimulated frequency pulses (Fig. 5a). The trigger circuit 36 with two stable states divides the frequency of the pulses of the generator 35 into two and reaches a constant filling factor of 1/2 (Fig. 5.6). The Trigger 37 circuit with two stable states again divides into two the frequency generated by circuit 36 (Fig. 5c). The rectangular pulses at the output of the circuit 36 are integrated by the integrating circuit 38, which forms a triangular voltage with peak protective pulses (Fig. Supplied to the input of the comparator assembled according to Wygtt flip-flop 39, together with a variable voltage signal from the potentiometer 40. At the output the comparator 39 produces pulses separated by pauses, the duration of which is determined by the level of the DC voltage from potentiometer 40 (Fig.). These pulses are fed to the input of the first 41 and second 42 logic circuits along with the signal E of latch 37. The output of logic cxeiM 41 and 42 which are diagrams of coincidence and are obtained pulses (Fig. 5, f and g), which have a duration of at luperiodu, and frequency equal to the operating

inverter frequency.

These half-period pulses are differentiated by the first 43 and second 44 differentiating chains, resulting in short differentiated pulses, phased from the beginning of the half-period pulses (Fig. 5h, i).

The inversion of these pulses is carried out by the logic circuits HE 45 and 46, their output signal is differentiated by the third 47 and fourth 48 differentiating circuits. At the output of these differentiating circuits, short pulses are obtained, phased with the end of the half-period pulses (Fig. 5J and k). one

All control pulses of the main thyristors 17-20 can be blocked by a constant voltage signal of the corresponding polarity, supplied from a trigger 72 circuit with two stable states, which is controlled by an OR 73 circuit. The OR 73 circuit is controlled by an input defined in this way control of the main thyristors from the following blocks. A start-up delay unit 74, which controls the fifth logic circuit 75 and blocks the pulses starting from the moment the power supply is connected to the electronic circuitry and up to a certain point after the delay time has elapsed, setting 738. The resulting differentiated pulses are fed to circuits 49-52 with one stable state, which create pulses of constant duration, then amplified by the first - fourth pulse amplifiers 53-56, which feed the primary windings of the first to fourth pulse transformers 57-60. In the secondary windings of these transformers, control pulses are received for extinguishing thyristors. The Schmitt trigger circuit inputs 61 and 62 are fed with 500 Hz pulses generated by the self-oscillating circuit 63, which are transmitted to the two output circuits of the Istta 61 and 62 only during the half-period existence of the signal (Fig. And t). The pulses at the output of the circuits 61 and 62 are opposite in phase and are fed to the input of the fifth to eighth pulse amplifiers 64-67, which feed the fifth to eighth pulse transformers 68-71. The secondary windings of the fifth and sixth transformers 68 and 69 are connected in pairs and are designed for controlling the main thyristors 17 and 20 in the diagonal of the converter with a pulse duration equal to the duration of the conduction of the main thyristors. The secondary windings of the seventh 70 and eighth 71 transformers are pairwise connected and designed to control the main thyristors 18 and 19 in another diagonal of the converter with a pulse duration equal to the duration of the state of conduction of the main thyristors. It is the beginning of the appearance of a half-period pulse. This o6pa30Mj after the expiration of some time after switching on the power supply of the electronic circuits ensures the simultaneous existence of control pulses of the main thyristors (plot i) and a charge pulse of the extinguishing capacitors (Fig. 5JnJ). An internal short circuit protection unit 76, to the input of which a voltage signal is supplied from a resistive divider 16 (FIG. 1). At the time of polarity reversal of the supply voltage of the converter in the event that an internal short circuit is formed, this unit generates a pulse to control the OR circuit 73 The voltage protection unit 77 from the output of the converter, to the input of which the voltage signal from the transformer 7 arrives (Fig. 1), which determines if the voltage at the output of the converter is within certain limits. If these limiting values are exceeded, then the circuit 77 controls the OR circuit 73 and blocks the main thyristors 17-20 and, through the circuit 78 controls the tripping of switch 3 (FIG. 1) after a period of approximately 3s. The stop button 79 is activated when the sequence of the converter is turned off, which consists in blocking the main pulses through the OR circuit 73 and the trigger 72 and in the control of the circuit 78 to disconnect the switch 3 (Fig. 1). The DC protection unit 80 in the output voltage of the converter, to the input of which the output voltage of the converter 2 arrives. If the difference between the positive and negative half-cycles of the output voltage exceeds the value determined with a given accuracy, block 80 protection generates a voltage signal after a predetermined period of time, and commands are given to block the main pulses, as well as turn off the converter. The protection of the converter from an external short for 1 scan is achieved by the protection unit 81 against an external short circuit, which is controlled by a current transformer 6 (Fig. 1). If the load current exceeds the maximum predetermined value, the circuit 81 generates a voltage signal that controls the control circuit 82 of the short-circuit switch 11 (FIG. 1) and the signal circuit 83. The operating frequency of the converter is set by the frequency switch 84 (FIG. 3). If the switch is shifted from a frequency of 16 2/3 Hz to a frequency of 22 Hz during operation of the converter, this means that the O position has been passed, the pulses are blocked and the converter is turned off by the circuit OR 73. The operating frequency changes while the converter does not work. The load of the converter is connected by means of closing the switch 4 (Fig. 1), which is controlled by the circuit 85 (Fig. 4). A static frequency converter with a DC link, including the proposed control device, is highly reliable due to the presence of the necessary protective equipment for each individual case and is characterized by relatively low costs in its manufacture.

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Claims (2)

1. CONTROL DEVICE 'STATIC FREQUENCY CONVERTER with rectifier, inverter and inductor with a tap from the midpoint, containing a master oscillator, pulse distributor, control pulse generator, pulse amplifiers of main thyristors and quenching thyristors with output pulse protection transformers, central unit , a start-up and shutdown circuit of a statistical converter, characterized in that, in order to increase the reliability of operation, the first input of the central protection node is connected it is connected with an internal short circuit detector through an inverter, the second input - with the output of the input protection unit when the voltage deviates from the permissible limits, the third - with the output of the external short circuit protection unit, the fourth - with the output of the protection unit from the DC component, and the output of the central the protection node is connected to the first input of the pulse distributor, and with the entered power-off circuit and with the short-circuit introduced, which is connected between the midpoint of the inductor and the common exit point and a rectifier input, an inverter, and the input and disable tsepi.zapuska static converter connected to the first output of the pulse distributor, the output of this circuit is connected to the switch converter load inputted and a second input pulse distributor. § owls, the third input of the pulse distributor is connected to the output of the master (generator, the fourth input of the pulse distributor is connected to the output of the control pulse generator, and the others ₍ outputs of the pulse distributor are connected · ^{: are} connected to the pulse amplifiers of the thyristor SU 1148573 ₄ damping pulses, with pulse amplifiers (Main thyristors and with inputs - blocking of amplifiers of impulses of the main thyristors. 2. Device pop. 1, distinguished by the fact that the pulse distributor contains two frequency dividers ^:: you, whose midpoint is connected · 'to the input of the integrating circuit, the output of which is connected to the trigger input Schmitt, whose second input is connected to a potentiometer, and the outputs of the trigger and the second frequency divider are connected to the input of the first and second logic circuits AND, the outputs of which are connected to the input of the first and second differentiating circuits and the inputs of two in ¹¹⁴ version circuits, the outputs of which are connected with the inputs of the third and fourth differentiating circuits, the outputs of each of the differentiating circuits are connected to the inputs of the instability circuits, the outputs of which are the second output of the pulse distributor and connected to the inputs of the first four amplifiers pulses that are connected to the primary windings of the first four dividing pulse transformers of the quenching thyristors, the third and fourth logic circuits Й, the outputs of which are the third output of the pulse distributor connected by two inputs to the outputs 573 of the first logic circuits And, and the outputs of the third and fourth logic circuits And connected through pulse amplifiers to the primary windings of the other four isolation transformer transformers of the main inverter, a trigger, the first input of which is connected to the output of the start and stop circuit, the second input of the trigger is connected to the output of the central protection unit, and the output of the trigger is connected to the outputs of the block of pulse amplifiers the main thyristors of the inverter and is a quarter-hour output of the dec., pulse limiter.