SU653719A1 - Power-diode converter control device - Google Patents

Description

one

The present invention relates to electrical engineering, devices for pulse-phase control of static bridge converters and can be widely used in various electrical installations, in particular - in powerful stabilized power sources based on static converters of direct current, in an electric drive of direct current.

A device for controlling a valve converter 1 is known, which is intended for pulse-phase control of a valve converter with a single-channel formation of antiphase control pulses.

The disadvantage of this device is the asymmetry of the output pulses.

Of the known devices for controlling the valve converter, the closest to the technical essence of this invention is a device for controlling the valve converter 2, which contains a source of synchronization voltage connected to the input of a null indicator, an integrator with a reset switch, connected to the input of the comparator, and an output pulse generator. by duration.

In this device, the synchronizing voltage is rectified by a rectifier and is applied to a null indicator with a constant input offset. The disadvantage of this device is that the time points corresponding to the beginning of the formation of the sawtooth reference voltage by the integrator depend on the voltage drops in the rectifier diodes and their spread, which does not allow for the same phase shift between the reference voltages of different phases. This results in an unequal phase shift between the output pulses of different phases. These drawbacks increase the asymmetry of the output pulses of the device.

The aim of the present invention is to reduce the asymmetry of the output pulses of the device.

Claims (2)

The goal is achieved by the fact that a device for controlling a valve converter, containing a source of synchronization voltage, connected to the input of a null indicator, an integrator with a reset switch, connected to the input of the comparator, and a shaper of output pulses in duration, is additionally equipped with a shaper of synchronizing pulses and RS- trigger, the output of the null indicator is connected to the input of the synchronization pulse generator, and the output of the latter is connected to one of the RS-flip-flop inputs, output d is connected to the control circuit of the integrator reset key and to an input of the output pulse duration, and to another input of RS-flip-flop connected to the output of the comparator. The invention is illustrated in the drawings, where in FIG. 1 is a diagram of a device for controlling a valve converter, and FIG. 2 - timing charts of the device. The device for controlling the valve converter contains a source of synchronization voltage 1 connected to the input of the null indicator 2. The output of the null indicator 2 is connected to the input of the generator of synchronizing pulses 3, the output of which is connected to one of the inputs of the RS flip-flop 4. The output of the trigger 4 is connected to the control the circuits of the reset key 5 of the integrator 6 and to the input of the output pulse shaper by duration 7. The stabilized current Jo arrives at the input of the integrator 6. The output of the integrator 6 is connected to one of the inputs of the comparator 8, to the other input of which the control voltage Uu is fed. The output of the comparator 8 is connected to another input of the RS flip-flop 4. The device operates as follows. In the initial state, when the voltage at the input of the source of the synchronizing voltage 1 is absent, there are no pulses at the output of the generator of the synchronizing pulses 3. The trigger 4 is in a steady state corresponding to the closed state of the reset key 5 of the integrator 6. In this case, the output voltages of the integrator 6 and the comparator 8 are zero. Pulses at the output of the output pulse shaper for duration 7 are absent. When the voltage source 1 is applied to the input of the voltage source of the network, a synchronization voltage is formed at its output (Fig. 2a). At the same time, the zero indicator 2 at the moments of the transition of the synchronizing voltage through zero switches, and a rectangular voltage is formed at its output (Fig. 26), which enters the input of the synchronization pulse generator 3. Short pulses appear at the output of the synchronization pulse generator 3 (Fig. 2c), the front of which corresponds to the transition of the synchronizing voltage through zero. The frequency of these pulses is equal to twice the frequency of the network. The first output pulse from the synchronization pulse generator 3 switches the trigger 4 to the opposite steady state (Fig. 2i), which opens the reset key 5 of the integrator 6. A sawtooth voltage is formed at the output of the integrator 6 (Fig. 2e). At the moment of time corresponding to the instantaneous values of the output voltage of the integrator 6 and the control voltage Ui (Fig. 2e), the comparator 8 switches (Fig. 2e), which causes the switching of trigger 4 (Fig. 2d), the closure of the reset key 5 of the integrator 6 and resetting it (Fig. 2d), forming the output pulse in the pulse shaper of duration 7 (Fig. 2g) and returning the comparator 8 to the initial state (Fig. 2e). At the instants of time, corresponding to the following sync voltage zero crossing, the processes in the device are repeated. At the output of the device (output of the output pulse generator for a duration of 7), double frequency pulses are generated compared to the network frequency, the phase shift of which relative to the time of the synchronizing voltage crossing through zero is determined by the amplitude of the control voltage Ui. When controlling a multiphase converter, the number of control devices must be equal to the number of phases of the converter. If this device is used to control the converter on the triacs, the pulses from the driver 7 are sent directly to the triacs of the respective phases. If this device is used to control the converter on the thyristors, the output pulses from the former 7 are sent to the distributor and pulses (not shown in Fig. 1), where they are distributed across the antiphase thyristors. Thus, the use of a synchronizing pulse and trigger triggered by the integrator-comparator-integrator in the feedback device increases the stability of the formation of the phase shift of the pulses, which reduces the asymmetry of the control pulses of the converter valves by 1.5-2 times. An apparatus for controlling a valve converter, comprising a source of synchronization voltage, connected to the input of a null indicator, an integrator with a reset key, connected to the input of a comparator, and a shaper of output pulses in duration, in order to reduce the asymmetry of the output pulses additionally equipped with a synchronization pulse shaper and an RS trigger, with the output of the indicator connected to the input of the sync pulse generator, and the output n The last one is connected to one of the RS-flip-flop inputs, the output of which is connected to the control circuit of the reset key of the integrator and to the input of the output pulse shaper by duration, and the other RS-flip-flop input is connected to the comparator output. Information sources taken into account during the examination 1. Anisim L. F. Features of the use of semiconductor converters in ship electrical installations - L., “Shipbuilding, 1973, p. 44-47, fig. 210, 211. 2. Express information VINITI, “Automated electric drive. Electrotechnology. Power supply. Power converting technology. Moscow, No. 27, 1976, p. 14, fig. 2 Network I 1 I -one