RU1781804C - Device for control over parallel current inverter with rectifier-inductive compensator - Google Patents

Abstract

The device comprises an input inverter smoothing reactor 1, a gate bridge of the inverter on thyristors 2-7, commutator n, 15 Haii ,, and nbsp; nbsp; A & / # h capacitors 8-10, two rectifier bridges of the compensator on thyristors 11- 16, 17-22, switching reactors 23, 24, current sensors 25, 26, master distribution generator 27, inverter control pulse shapers 28, compensator control pulse shapers 29, control voltage shaper 30, linear voltage generator 31 m inverter, single vibration Orae 33 and 32. The compensator control units 34-39 each of which includes an AND 40, delay element 41 the pulse front, RS- trigger 42, the phase-shifting block 43 and the element 44. The AND-NO 2 yl. w Yo 23 aK, and ntsc.yyy A & / # h VJ 00 00 about 4

Description

The invention relates to a converter technique, in particular to devices for controlling DC / AC converters using a current inverter.

A device is known for controlling a parallel current inverter with a rectifier-inductive compensator, comprising a master pulse distributor, the outputs of which are connected to the inputs of the pulse shapers of the control of the yvertor, control blocks of the compensator according to the number of control channels, each of which contains a phase-shifting block controlling the input of which through the common for all channels the control voltage driver is connected to the terminals for connection to the inverter output, the outputs of the control units to the compensator through the shapers of the control pulses of the compensator are connected to the terminals for connecting to the thyristors of the compensator, and the outputs of the shapers of the control pulses of the inverter are designed to connect to the thyristors of the inverter, the clock generator along the line voltages of the inverter and each control block of the compensator is equipped with an RS trigger, an edge delay element pulse elements And and NAND, and the inputs of the driver of the clock on the linear voltages of the inverter are connected to the outputs of the control voltage converter, adjacent outputs of the inverter of the synchronous pulses along the linear voltages of the inverter are paired with the outputs of the element And in each control unit of the compensator, in which the output of the element And through the delay element of the pulse front is connected to the first input of the AND gate, the output of which is is the output of the compensator control unit, the R-input of the RS-trigger is connected to the corresponding output of the master oscillator - pulse distributor, the output of the RS-trigger is connected to the second input of the AND-NOT element The main input is phase-. flashing unit, the output of which is connected to the S-input of the RS-trigger.

A disadvantage of the device is the possibility of failure of the inverter switching and the emergence of an emergency mode in the converter when the allowed zone of regulation of the angle of control of the compensator thyristor by the thyristor current coming out of operation is blocked.

The purpose of the invention is to increase reliability.

The goal is achieved in that a device for controlling a parallel current inverter with a rectifier-inductive compensator, containing a master generator-distributor

pulses, the outputs of which are connected to the inputs of the pulse shapers for controlling the inverter, the outputs of which are designed to be connected to thyristors

0 inverter, generator of clock pulses according to the linear voltage of the inverter, control units for the compensator according to the number of control channels, each of which contains an RS trigger, delay element

5 pulse edges, AND-AND-NOT elements and a phase-shifting unit, the control input of which is connected to the terminals through the common driver of the control voltage to the terminals for connection to

0 to the inverter output, the inputs of the inverter of the clock pulses are connected to the outputs of the inverter of the control voltage along the linear voltages of the inverter, the adjacent outputs of the inverter are synchronized.

5 pulses along the inverter linear voltages are connected in pairs to the outputs of the And element in each compensator control unit, in which the output of the And element is through the delay element of the pulse front

0 is connected to the first input of an AND-NOT element, the output of which is used as the output of the compensator control unit and connected to the outputs for connecting to the compensator thyristors via the corresponding compensator control pulse generator, the R-input of the RS-trigger is connected to the corresponding output of the master pulse generator , the output of the RS trigger is connected to the second input

0 AND-NOT element with a synchronizing input of the phase-shifting unit, the output of which is connected to the S-input of the RS-trigger, is additionally equipped with two current sensors, each of which is designed to

5 including in the DC circuit of the corresponding compensator bridge, with two single vibrators, in each compensator control unit the NAND element is equipped with two additional inputs, moreover

0 the outputs of the first and second current sensors are connected respectively to the outputs of the first and second single vibrators to the third inputs of the corresponding elements of the NAND control units of the compensator, and the outputs of the first and second single vibrators are connected to the fourth inputs of the same elements of the NAND.

In FIG. 1 is a functional diagram of a device for controlling a parallel current inverter with a rectifier-inductive compensator; Fig. 2 is a voltage diagram illustrating the operation of the device.

The device comprises an input inverter smoothing reactor 1, an inverter valve bridge on thyristors 2-7, switching capacitors 8-10, two rectifier compensator bridges on thyristors 11-1 b and 17-22, switching reactors 23, 24, current sensors 25, 26 specifying the distribution generator 27, inverter control pulse shapers 28, compensator control pulse shapers 29, control voltage driver 30, inverter linear voltage generator 31, single vibrators 32, 33 and computer control units the sensor 34-39, each of which consists of an element And 40, an element 41 of the delay 41 delay of the front of the pulses, RS-flip-flop 42, phase-shifting unit 43 and the element AND-NOT 44.

The outputs of the generator-distributor 27 are connected to the inputs of the formers 28 and the R-inputs of the trigger 42 of the blocks 34-39. The outputs of the formers 28 are connected to the control electrodes of the thyristors 2-7 of the inverter. Voltage is supplied from the output terminals of the inverter to the inputs of the driver 30 (11d, UB, DC) and the driver 31 (UAB UBC UCA). The corresponding outputs of the driver 31 are connected in pairs to the inputs of the element 40, in each block 34-39. The output of element 40 is connected to the input of element 41, the output of trigger 42 is connected to the clock input of the phase-shifting unit 43 and the first input of element 44. The first inputs of blocks 43 in each control unit of compensator 34-39 are connected to the output of former 30. The output of the phase-shifting unit 43 is connected to S- the trigger input 42, the output of the element 41 is connected to the second input of the element 44. The outputs of the blocks 34-39 are connected to the shapers 29, which, in turn, are connected to the control electrodes of the thyristors 11-16 and 17-22 of the compensator. The output of the current sensor 25 included in the DC circuit of the compensator bridge on thyristors 11-16 is connected to the input of the single-shot 32 and the third inputs of the elements 44 of the blocks 34-36. The output of the current sensor 26 included in the DC circuit of the compensator bridge on the thyristors 17-22 is connected to the input of the single-vibrator 33 and to the third inputs of the NAND elements 37-39. The output of the single-shot 32 is connected to the fourth inputs of the AND-NOT element 44 of the blocks 34-36, and the output of the single-shot 33 is connected to the fourth inputs of the AND-NOT elements of blocks 37-39.

To prevent the occurrence of a continuous current mode through the reactors of the rectifier-inverter compensator, which leads to the overturning of the inverter 5, it is necessary that the minimum angle of control of the compensator valves be at least 30 electric degrees, and it is also necessary that the pulse to turn on the thyristor The compensator was applied after a time ts (necessary to restore the shutoff properties of the thyristor) after the current through the thyristor that went out of operation dropped to zero. Since blocks 34-39 are composed of similar elements and have equivalent connections

5 between them, it is enough to consider the work of one of them.

Pulses from the master oscillator-distributor 27 are fed to the R-input of the trigger 42, from the output of which they are fed to

0 input of block 43 for starting a ramp generator. At the moment of comparing the sawtooth voltage with the feedback voltage OOS coming from the shaper 30, a pulse is output from the output of the phase shifting unit 5 to the trigger 42 at the input S. As a result, a pulse with an adjustable cut-off moment is applied to the first input of the element 44 (Fig. . 2).

0 The range is limited as follows.

The linear output voltage of the inverter is supplied to the input of the driver 31, at the input of which a six-channel5 is generated to a system of pulses synchronized with the transition of the linear voltage of the inverter (UAB. UBC, UCA} through zero. Pulses shifted relative to each other by 120 el. on the

0 inputs of element 40. At the output of the latter, 60 electrical pulses are generated, the slice of which is rigidly attached to the point of transition of the linear voltage through zero. The front of these pulses determines

5 the allowed zone for regulating the compensation thyristor control pulse. To eliminate the effects of pulse asymmetry / phase control of the output voltage and the like. it is necessary to narrow the allowed zone for controlling the angle of control of the thyristor compensator, for which a fixed delay (of the order of 1-2 electric degrees) of the phase of the front of the pulses of the formed elements 40 is introduced. This delay is provided by the element 41, from which the pulses are fed to second input of element 44.

In dynamic modes of the inverter (cyclic load shedding, for example, work on the system

direct frequency inverter-asynchronous motor in emergency modes, it is possible to overlap the resolution zone in time with the thyristor current coming out of operation. When the next pair of thyristors is turned on according to the selected control algorithm (for example, after the thyristors 12 is shut down. 14 thyristors 13, 15 are turned on, Fig. 2), a short circuit between the phases of the inverter can occur.

 To eliminate this drawback, an additional sequence of pulses is generated from the current sensor of the compensator thyristors, which is supplied to the third input of element 44 from the output of the current sensor 25. To ensure the recovery time of the thyristors that are out of operation using the single-shot 32, an additional delay (IB) is generated at the trailing edge of the pulse from the output of element 44 (FIG.

2) Thus, the allowed zone for generating the compensator thyristor control signal, determined by the duration of single signals from the outputs of elements 40 and 42 according to the prototype, in some cases is reduced due to overlapping by zero signals from elements 25, 32. determining the conductive state of the thyristors, the output from work (for example, the dashed line in Fig. 2).

The use of the proposed device for controlling a parallel current inverter with a rectifier-inductive compensator with newly introduced elements will eliminate the possibility of a short circuit between the phases of the inverter, thereby providing increased reliability of the converter in dynamic operating modes.

Claims (1)

SUMMARY OF THE INVENTION A device for controlling a parallel current inverter with a rectifier-inductive compensator, comprising a master pulse distributor, the outputs of which are connected to the inputs of the inverter control pulse generators, the outputs of which are intended to be connected to the inverter thyristors, a synchronization generator for the inverter's linear voltage, compensator control units by number control channels, each of which contains an RS-flip-flop, a pulse edge delay element, AND and AND-NOT elements, and fa: a shifting unit whose control input is shared through all channels the control voltage driver is connected to the terminals for connecting to the inverter output, the inverter clock inputs are connected via the inverter line voltage to the control voltage generator outputs, the adjacent sync driver outputs on the inverter line voltage are connected in pairs to the outputs of the element And in compensator control unit, in which the output of the And element through the delay element of the pulse front is connected to the first input of the Y-NOT element, the output of which is used as the output of the block compensator control and connected through the appropriate compensator for pulse control of the compensator to the terminals for connecting to the thyristors by the compensator, the R-input of the RS-trigger is connected to the corresponding output of the master pulse generator-distributor, the output of the RS-trigger is connected to the second input of the NAND element and to the synchronizing input of the phase-shifting unit, the output which is connected to the S-input RS flip-flop, characterized in that, in order to increase reliability, it is equipped with two current sensors, each of which is designed to include in the DC circuit of the corresponding bridge the compensator, two single vibrators, in each control unit of the compensator, the NAND element is equipped with two additional inputs, and the outputs of the first and second current sensors are connected respectively to the outputs of the first and second single vibrators and to the third inputs of the corresponding elements of NAND control units of the compensator, and the outputs of the first and second single vibrators are connected to the fourth inputs of the same elements AND NOT. fax.te Ј & .W t / rf & P / Z