RU1802391C - Device for control over multicell d c/d c converter - Google Patents

Abstract

The device for controlling the converter comprises a pulse generator 9, a trigger -11, a control signal amplifier 12, a comparator 13, a feedback circuit 14, a current sensor 15, a delay circuit 16, a trigger 11, a transistor 18, a transformer 20, diodes 23, 24. 3 3-.P. f-ly, 2 ill.

Description

The invention relates to electrical engineering and can be used in secondary power supply systems of various radio-electronic equipment,

The aim of the invention is to increase the reliability of the converter by equalizing the currents of the power cells.

In FIG. 1 shows a circuit diagram of the proposed device; Fig. 2 is a diagram of voltages and currents explaining the operation of the device.

A device for controlling a converter made in the form of power cells 1 and 2, including transistor switches 3 and 4, chokes 5 and 6, and rectifiers 7 and 8, respectively, contains a pulse generator 9, the output of which is connected to the control input 10 of trigger 11 , a control signal amplifier 12, a comparator 13, the first input connected to the output of the feedback circuit 14, and the second input to the current sensor 15. A delay circuit 16 is connected to the output of the comparator 13, the output of which is connected to the blocking input 17 of the trigger 11, and the input of the transistor 18, the collector of which is connected to the potential power bus through the primary winding 19 of the transformer 20. The secondary windings 21 and 22 of the transformer 20 through the diodes 23 and 24, respectively, are connected to the base-collector junctions of the transistor switches 3 and 4..

Delay circuit 16 may include in -. b capacitor 25 and resistor 26. The primary winding 19 of transformer 20 can be shunted by series-connected resistors 27 and diode 28. In addition, the device may include a threshold node 29, the output of which is connected to an additional blocking input 30 of trigger 11, position 31 in FIG. 1 indicates the inverter load.

The device operates as follows.

The generator 9 generates a sequence of short pulses Ug (see Fig. 2) with a constant repetition rate. At time t, the pulse of the generator 9 enters the input 10 of the trigger 11, abruptly translates it into a state in which its output voltage Un, which enters the input of the amplifier 12, transfers the transistor switches 3 and 4 of the power cells 1 and 2 to the open state nie. Further, in the primary winding circuits of the chokes 5 and 6, the current hs starts to increase linearly until t2, when the current reaches the value h, at which the signal of the sensor 15 is compared with the output signal of the circuit 14.

At time t2, the comparator 13 is activated, abruptly changing the polarity of the voltage Ui3 at the output, as a result of which the voltage Uie begins to change

the output of the delay circuit 16 and opens the transistor 18. This leads to a voltage on the primary (19) and secondary (21 and 22) windings of the transformer 20. Further, through the diodes 23, 24 and transistor

switches 3, 4 start to flow currents, as a result of which transistor switches 3, 4 change from a saturation state to a boundary (or close to it) mode.

At time ta, when the transition of keys 3 and 4

5 to the boundary mode ends, the voltage Die at the output of the delay circuit 10, supplied to the input 17 of the trigger 11, reaches the level Ui, and returns the trigger 11 to its initial state. Unsaturated

0, the transistor switches 3 and 4 are closed in a short time and almost simultaneously, since the time of their resorption is zero.

It should be noted that in this case, a sequential RC circuit including a capacitor 25 and a resistor 26 can serve as the simplest and most effective implementation of the delay circuit 16.

0 Further, the current lis in the primary winding circuits of the chokes 5 and 6 becomes equal to zero, and in the secondary winding circuits the current l (8), which flows through the rectifiers 7 and 8, flows to the load 31. Decreasing to

5, the signal of the current sensor 15 at time ta triggers the comparator 13, as a result of which the transistor 18 closes and the voltage across all windings of the transformer 20 becomes zero.

0 It should be noted that in some cases with a sufficiently large power of the device, the transformer 20 can accumulate significant energy during the open state of the transistor

5 to 18, which is typically 1 to 2 microseconds. In such cases, it is advisable. Parallel with the winding 19 of the transformer 20 to include a protective chain, including. sensing resistor 27 and diode 28. Then in

At time ta, the energy stored by the transformer 20 will be dissipated on the resistor 27 and diode 28, without creating overvoltages on the transistor 18 at the time of its closing.

5 at time t4, the reactors 5 and b transfer all the stored energy to load 31 and the current i (8) becomes equal to zero.

At time ts, the next pulse Ug of the generator 9 puts the trigger 11 in a state in which the transistor switches 3 and

4 are opened again and the process is repeated.

If at the moment te the output transforms: ell, a short circuit occurs, then closing at the moment ty the transistor of keys 3 and 4, the current i (B) practically does not decrease, since the voltage at the output is zero. Therefore, at time ts, when the transistor switches 3 and 4 open again, the current lis jumps up from almost to the maximum value reached at time t, and during the delay time fe-tg, the current hs rises to an even larger value.

; At the moment Ho, the transistor switches 3 and 4 sns | open and the current hs jumps up to the value reached in the modept tg, and during the time tto-tn has time to rise to Level 2, at which the signal of the current sensor 15 triggers a threshold node la Ј9. The voltage at the output of the threshold node 29 changes the polarity and, acting on the input 30, puts the trigger 11 in the state - 0, in which the transistor switches 3 and 4 are closed.

j At moments when the transistor switches $ and 4 open again, the current Hs almost instantly reaches level 2, which will trigger the threshold node 29, trigger 11 and close the transistor switches 3 and 4,

 Further, the process is repeated, and the rise in current Ms is stopped.

 Thus, in the proposed device, thanks to the introduction of a transistor, transformer, diodes and a delay circuit, transistor switches are taken out of saturation mode before they are turned off, which makes it possible to reduce resorption time to zero and to ensure that they close almost simultaneously. Due to this, the currents of the power cells are equalized and the reliability of the converter is increased.

I In addition, due to the introduction of the porous node, transistor keys are protected in the short circuit mode at the output of the converter by limiting the current at a given level. This | also contributes to the increase of the reliable ™ converter. . .

Claims (4)

The claims ;1. Device for controlling a multiple constant converter voltage, made in the form of N power cells, each of which contains a transistor switch and an LCD filter containing a current sensor, the potential terminal of which is designed to connect to the corresponding output of N power cells, and the zero terminal - with a common power bus, generator pulses, the output of which is connected to the control input of the trigger, the output of which through the amplifier of the control signal is designed to connect N power cells to the control input, and a feedback circuit, the output of which is connected to the first input an arator, the second input of which is connected to the potential output of the current sensor, characterized in that, in order to increase the reliability of the converter by equalizing the currents of the power cells, a transistor is introduced into it, the emitter of which is connected to a common power bus, and the base is connected to the output terminal of the comparator, a transformer having N secondary windings, each of which through an additional diode is designed to connect to the base-collector junction of the corresponding transistor switch, and a delay circuit connected to the output of the comparator, etc. than the transistor collector through the primary winding of the transformer is connected to the potential supply bus, and the output of the delay circuit is connected to the blocking input of the flip-flop. 2. The device pop. 1, characterized in that the delay circuit is made in the form of a serial RC circuit, the terminals of which are used as input terminals, and the capacitor terminals of an RC circuit as output terminals of a delay circuit. 3. The device according to paragraphs. 1 and 2, characterized in that the primary winding of the transformer is shunted by a chain containing a resistor and a diode connected in series. 4. The device according to paragraphs. 1-3, characterized in that a threshold node is introduced into it, the input of which is connected to the potential output of the current sensor, and the trigger is equipped with a second blocking input, which is connected to the output of the threshold node. cm w &