SU1598083A1 - Rectifier control method - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control AC-to-DC converters. The purpose of the invention is to reduce the influence of the asymmetry of the supply voltage on the output voltage of the rectifier. The variable component of the signal is formed from the voltage, which is proportional to the time interval between the moments of transition through zero phase and linear voltages. This variable component is then collapsed algebraically with the control signal and, using the vertical principle, form the control pulses of the valves. 1 il.

Description

The invention relates to electrical engineering and can be used to control AC-to-DC converters.

The purpose of the invention is to reduce the effect of the asymmetry of the supply voltage on the output voltage of the rectifier.

The drawing shows a diagram of the device for implementing the method.

According to the proposed method of controlling a rectifier, a sweeping periodic voltage is generated, synchronized with the moments of transition through zero of the linear voltages of the supply network. A voltage proportional to the time interval between the moments of transition through zero phase and linear voltages is formed, and a variable component is extracted from it, which is algebraically summed with the control voltage. The summed voltage is compared with the sweeping periodic voltage and at the moments of their equality form the control pulses of the respective rectifier valves.

A device for implementing a method of controlling a rectifier contains a first synchronizer 1, which generates pulses at the moments of a phase voltage network transition through zero, and a second synchronizer 2, which pulses at the moments of linear voltage transition through zero. The output of the first synchronizer 1 is connected to the input of the generator 3 of the sawtooth voltage and to the first input of the time converter 4 to the voltage, the second input of which is connected to the output of the second synchronizer 2. The output of the time converter 4 to the voltage is connected to the information input of the sampling unit 5 and storage, the operation of which is synchronized by the pulses of the synchronizer 1. The output of the block 5 of the sample and storage is connected to the subtractive input

(L

Yu

00 O 00

with

adder 6, the summing input of which is intended to be connected to a control voltage setting device. The output of the sawtooth generator 3 and the output of the adder 6 are connected respectively to the first and second inputs of the comparator 7. The output of the comparator 7 is connected to the input of the distributor 8, the outputs of which are connected to the control electrodes of the valves of the converter 10 through the unit 9.

The device works as follows.

The first 1 and second 2 synchronizers form pulse sequences whose pulse fronts coincide, respectively, with transitions through zero linear and phase voltages of the supply mains. Along the pulse fronts of the first synchronizer, a generator 3 of the saw-tooth voltage is started, which forms a linearly developable voltage. The time interval to voltage converter 4 also forms a linearly developable voltage at intervals between the pulses of the second 2 and first 1 synchronizers, the value of which UK is read by the sampling and storage unit 5 on the pulse front of the first synchronizer 1.

The control voltage is formed by adding the control signal Uy to a voltage of approx. proportional to the time interval between the pulse fronts of the second 2 and first 1 synchronizers, in the absence of asymmetry of the supply voltage, from which the UK voltage at the output of the sampling and storage unit 5 is subtracted from the adder 6. The total voltage at the output of the adder, 6 is compared by the comparator 7 with the voltage of the generator 4 of the saw-tooth voltage, and at the moments of their equality they generate pulses for controlling the valves. The turn

The constancy and correspondence of the supply of control pulses to the valves of the rectifier 10 are determined by the operation of the distributor 8 of pulses. The pulse shaping drivers 9 are designed to amplify the control pulses with the formation of their optimum shape, as well as to provide galvanic isolation of the control circuits from the power unit.

The relationship between amplitude signals and signals proportional to angular magnitudes is linear, since the deviation of the amplitude of the supply voltage is usually small and ranges up to 5%.

Thus, the proposed method makes it possible to reduce the influence of the asymmetry of the mains voltage on the output voltage of the rectifier, and compensation is carried out on the same control cycle as the asymmetry is detected.

Claims (1)

The invention The method of controlling a rectifier, consisting of an HTM, that forms a sweeping periodic voltage synchronized with the moments of crossing the linear voltage of the supply network through zero, is compared with the controlling voltage, and when they are equal, generate pulses of control of the corresponding rectifier valves, characterized in that, in order to reduce the influence of the asymmetry of the supply voltages on the output voltage of the rectifier, a voltage is formed that is proportional to the time interval between By the moments of passing through zero phase and linear voltages of the mains supply, the variable component is extracted from it and the control voltage is adjusted by the value of the variable component by algebraic summation. Ucemu m w ,