SU1244760A1 - Stabilized d.c.voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power sources. The purpose of the invention is to increase efficiency. The device contains an inverter 1, a rectifying and filtering unit 3, a control unit (CU) 5, a switching unit (CU) 10. The execution of the switch 9 of the CU 10 at the switching contacts of the electromechanical relay and connecting through the breaking contacts 13, 14 and the ballast resistor 15 of the capacitor 1 1 to the input, and through the closing contacts 7, 8 - to the power supply buses of the CU 5 provide an increase in efficiency. This improvement automatically simultaneously polls the output state of the stabilized inverter, and also when the overload or short circuit is removed, the inverter automatically switches on. With low voltage, power supply, the device is simple and cheap. In BP 10, a clock pulse generator (GTI), a control signal generator and a two-level comparator are inserted, which allows the signal on the comparator to change as the output voltage decreases to the second trigger threshold. An option for performing a GTI on a single junction transistor is shown. ZP f-ly, 4 ill. from $ (L to 4 ijib od

Description

one

The invention relates to electrical engineering and can be used in the construction of sources of secondary power. ...

The purpose of the invention is to increase efficiency.

FIG. 1 is a schematic of a stabilized DC converter in FIG. 2 shows a circuit of a switching unit with advanced functions according to the magnitude of the current and the charging time of the capacitor; in FIG. 3, a functional electrical circuit of the switching unit allowing setting the rotation period of its connection to busbars. in fig. four . schematic diagram of the switching unit.

The stabilized DC voltage converter (Fig. 1) contains an inverter 1 connected by a power input to the input-outputs 2. The output of the inverter 1 is connected via output block 4 to the output pins 4, which are simultaneously connected to the output of the unit 5 control directly and the power supply bus of this unit through a rectifier (diode) 6 ..

The output of the control unit 5 is connected to the control input of the inverter 1. The power supply busses of the control unit 5 are connected through a trailing electromagne. Chanical contacts 7, 8, included in the switch 9 of the switching unit 10, to the capacitor 11. The capacitor 11, in parallel with which the measuring element 12 of the switching unit is connected, by means of disconnecting electromechanical contacts 13, 14, included in the switch 9 of the switching unit 10, connected to the input and terminals 2 through the ballast resistor 15.

Stabilized Converter works as follows.

At the moment of switching on the stabilized converter, the source of the input terminals 2 is supplied simultaneously to the inverter 1 and through the ballast resistor 15 and the normally closed contacts 13 and 14 to the capacitor 11 and the measuring element 12 of the switching unit 10.

Inverter 1 does not work, because the necessary input signal is missing at its control input, because of the 44760 2 supply to control unit 5

no yielding. The capacitor 11 is charged through the ballast resistor 15. When it reaches the specified

the voltage values of the measuring 5 element 12 is triggered, opens

pins 13, 14 and closes the pins

7, 8J of the connection is thus charged, the capacitor 11 to the power busbars of the control circuit 5. By electric

0 of the charge accumulated by the capacitor 11, the control unit 5 starts operating and sends the corresponding signals to the control input of the inverter 1. which is starting to convert pos /

15 This voltage is applied to input pins 2 to AC. The alternating voltage of the required value from the output of the inverter 1 is supplied to the rectifying and filtering unit 3, where it is

20 is converted to the desired constant voltage and where the variable components are filtered. Filtered DC voltage is applied to output pins 4, input

25 of the control unit 5 and through diode 6 to the power supply buses of the unit 5. 1 If there is no overload or short circuit, then the power supply of the control unit 5 after start-up takes 30 s from the stabilized output 4, which is maintained by the measuring element 12 of the switch 9 in the state when the contacts 7, 8 are closed and the condenser.or 1 1 is connected

35 to the power buses of the control unit 5. If on the stabilized inverter code there is a short circuit or overload, i.e. voltage at stabilized output does not reach

40 of the required size, the measuring element 12 opens. Contacts 7, V

and closes the contacts .13, 14. The capacitor 11 begins to charge and the process is repeated. Consequently,

45, the switching unit 10 in this case also performs the role of a device automatically polling the output state of the stabilized inverter. When the overload or short circuit of the stabilized converter is removed, the switching unit 10 switches it on automatically.

In the case where the switch 55 is a low-voltage electromagnetic direct current relay, the device is extremely simple and has the least cost.

However, for direct current relays, the thresholds for switching it on and off are not sufficient, and from sample to sample they vary within wide limits. This is a significant disadvantage of this device, since, when the switching voltage of the relay is low, the energy stored in the capacitor 11 and the voltage across it may be insufficient to start the control unit 5 and, accordingly, the inverter 1. A low voltage - switching off the relay is dangerous in that when the inverter is overloaded, the power to the control circuit is supplied for some time from the capacitor 11. Active elements, such as inverter transistors, enter active mode of operation, which can lead to failure.

More sophisticated. is a switching unit 1, the functional scheme of which, besides the winding of the electromagnetic relay 16 of a constant current with electromechanical contacts G 7, 8 and 13, 14, contains an electronic key

17 and a two-level constant-voltage comparator 18, the relay coil being connected to a capacitor

11 via an electronic switch 17, the control input of which is connected to the output of a constant voltage comparator 18.

The device works as follows. .

The capacitor 11 is charged, as before, through normally closed contacts 13, 14 and the ballast resistor 15, when the voltage on the capacitor 11 reaches a predetermined value — the first level of 1 parator

18 constant voltage. Comparato 18 generates a signal that opens the electronic key 17 and turns on the relay coil 16, which opens the contacts 13, 14 and closes the contacts

7 and 8, supplying power to the control unit 5. If the voltage on the capacitor 11 has decreased, but has not reached a certain predetermined value - the second level of the constant voltage comparator 78, then the state of the relay does not change and the capacitor 11 remains connected to the power buses of the control unit 5 (Fig. 1). the capacitor 11 is reduced to the second level of triggering of the comparator 18, the signal

at the output of the comparator 18, it changes in a jump-like manner so that the electronic switch 17 closes and interrupts the coil through the winding of the electromagnetic relay 16, as a result of which the contacts 7, 8 open and the contacts 13, 14 close. The capacitor 11 starts to charge again through the ballast resistor 15 and closed contacts 13, 14. The process of switching the capacitor 11 is repeated. If there is an overload at the output of the converter, then, as before, the switching unit 10 automatically switches it on after a certain period.

However, using this scheme, it is impossible to regulate this period over a wide range, since the charging time of capacitor 11 cannot be very large due to the large leakage currents of capacitor 11, which, as a rule, is an electrolytic capacitor.

This disadvantage is eliminated in the circuit of block 10, where an additional generator, 19 clock pulses, and a control signal generator 20 are introduced. In this case, the control input of the electronic capacitor 17 is connected to the outputs of a two-level DC voltage comparator 18 and to the generator of 19 clock pulses through the control signal generator 20..

The difference between the operation of this device and that described above is that after the voltage on the capacitor 11 reaches the first threshold of the comparator 18, it is connected to the power supply of the clock generator 19 and at the same time, from the output of the comparator 18, a signal to the driver 20 of the control signal. However, the signal at the output of the driver 20 of the control signal is changed only when the second output of the generator also receives a signal from the output of the 19 clock pulse generator. Thereafter, the control signal at the input of the electronic key 17 opens this key and keeps it open until the signal at the output of the comparator 18 changes. The signal at the output of the comparator 18 is changed only when the output voltage of the converter decreases to the second threshold for the comparator 18 to operate.

In the switching unit 10, the clock pulse generator 19 is made on a single junction transistor 21, a trigger on the tunnel diode 22 is used as the control signal generator 20. The electronic key 17 is a bipolar transistor, a two-level comparator 18 is made on zener diodes 23, 24 and a bipolar transistor .25.

Formula Invention

Claims (1)

1. A stabilized DC / DC converter containing an inverter, a straightening and filtering unit, a capacitor, a ballast resistor, a switching unit with a measuring input and a switch, and a rectifier connected to the output terminals connected through a straightening unit and a phi i with an output of an inverter connected by a power input to the input pins, and a control input to the output; a control unit, connected to the output pins, and power buses through a switching unit switch with cond The sensor is connected to the measuring input of the switching unit, and the ballast resistor is connected to the first input terminal by the first output, which is connected with the fact that, in order to increase the CCT, the specified switch is made on at least one pair of switching contacts elect0 five 0: five 0 a romechanical relay, the capacitor is connected to the output terminals through the breaker contacts of the switch and the brigade resistor, and to the control unit connected to the output of the rectifier, through the switching resistors. 2, the converter according to claim 1, o-t, in that the switching unit is made on an electromagnetic relay with two pairs of switching contacts, the winding of which is connected parallel to the capacitor. 3 "Converter according to claim 1, that is: the switching unit is provided with an electrode key, a two-level DC voltage comparator and an electromagnetic relay with at least one pair of change-over contacts, the winding of which through the electronic key is connected in parallel with a capacitor, The control input of the electronic key is connected to the output of a DC voltage comparator, the input of which is connected in parallel to a capacitor. 4 „Converter on PP. 1 and 3, characterized in that., The switching unit is equipped with a clock pulse generator and a control signal generator, wherein the control input of said electronic key is connected to the output of a constant voltage comparator and with the code of the clock pulse generator management fi $ .2 .-. . . . zn fig.Z.