SU836754A1 - Bridge converter control device - Google Patents

Description

(54) DEVICE FOR CONTROLLING THE BRIDGE CONVERTER

Claims (3)

 I,. The invention relates to a conversion technique and can be used to control multiphase semiconductor rectifiers. A conventional device for controlling multi-phase converters is known, which allows automatic control of voltage by changing the control angle. It contains a clock generator, a master, a slave and a reversible counter, two decoders, a code equality circuit and a unit for automatically determining the phase angle D1. The drawback of the device is the complexity and the large number of functional units. The closest in technical essence and the achieved result to the proposed device is a device for controlling a bridge converter, which contains a clock pulse generator connected to the counting input of the first counter. the second counter, a comparator, the inputs of which are connected to the mains, and the output to the first input of the logic unit 2. A disadvantage of this device is its complexity due to the need to convert digital signals to analog signals and then convert them in a pulse, which reduces the reliability of the device. invention - improving the reliability of the device. This is achieved by the fact that a device for controlling a bridge converter, containing a clock pulse generator, connected to the counting input of the first counter, a second counting comparator whose inputs are connected to the supply network, and the output to the first input of the logic unit is provided with a key element and a memory element, and the first counter is provided with an installation and an additional input, and the output of the first counter is connected to the installation input of the second counter and the second input of the logic unit, the output of the second counter connects with the first input of the memory element and the control input of the claochion element whose output is connected to the second counter, and the input to the output of the clock generator, the comparator output is connected to the secondary input of the first counter and the second input of the memory element, output which is connected to the third input of the logic unit. FIG. 1 is a schematic diagram of a device for controlling a l bcTOBHM converter; 2, a diagram of the operation of the proposed device for controlling a three-phase rectifier circuit is shown in Fig. 2. Counter J has two inputs: counting input 2, connected to the output of key element 3, and setup input Reset 4, connected to input 5 of logic unit 6. The output of counter 1 is connected to input 7 of memory element 8 and control input 9 of the key element 3. The output of the memory element 8 is connected to the input 10 of the logic unit. The input 4 of the counter 1 is also connected to the output of the first counter 11, which is made with the possibility of setting the initial code on the input 12 and stopping during the overflow. The counting input 13 of the counter 11 and the input 14 of the key element are connected to the output of the clock generator (not shown in the drawings). Auxiliary input Starting 15 counting clock 11, input 16 of memory element 8 8 input 17 of logic unit 6 of SV1 with the output of comparator 18, the input of which is connected to mains 19. The input of comparator 18 is fed by a network. With the aid of the comparator, three sequences of pulses of duration 180 e are formed. degrees, whose fronts are synchronized with zero linear stresses Uj. The leading fronts directly start counter 11. Counter 10 is re-mixed after passing 13 UsA-Gl to its input & clock generator, where A is the counter capacity U is the regulation of the ball, equal to the required value of the angle of adjustment ct in the inverse code. The frequency of the clock generator is chosen based on the ratio, 360fc Ai 4 where is the frequency of the mains supply; d sA, (el.grad.) - the step of changing the angle of regulation. For example, to obtain a step of adjusting the angle oi equal to 1 al., With ff. 50 Hz f-18 kHz required. Thus, the overflow signal and on. The output of counter 11 appears at time t. corresponding to a given control angle cc, counted from zero linear voltage. At this time, the counter 11 is stopped. The leading edge of the overflow signal is reset by the counter 1. The signal at its output becomes a logical zero. The key element 3 opens and transmits the clock pulses to the counting input 2 of counter I. When n pulses pass at the output of counter 1, a signal appears that locks the key element 3 and stops the flow of clock pulses to the counting input 2 of counter 1. In this case, the pulse n is determined by the necessary sharp angular shift of os, the control voltages on the control circuit of the valves of the anodic and cathodic transducer groups. With a symmetric control of a three-phase bridge rectifier, the angle of the SC is equal to 60 electrical degrees. The rising edge of the signal U is started by the memory element I, and a logical unit appears at its output. The memory element is reset by the falling edges of the voltage of the comparator 18. Thus, the inputs of the logic unit 6 receive voltage from the comparator 18, the overflow signal of the counter 1 and the signal Ug from the output of the memory element 8. The logic device converts these signals into six sequences dashuls a, b, c, a, e, f with a duration of 120 electr., shifted relative to the zeros of the linear voltages of the supply network by an angle d. From the output of the logic device, the signals are distributed along the control circuits of the converter valves. In this case, various ways to control the valves can be implemented. For example, when using fully controlled valves of the transistor type, the output signals of a logic device are fed through buffer stages directly to the control circuits of the valves. If the power part of the converter is made on thyristors, amplifiers forming direct control pulses of the required duration and amplitude synchronized with the leading edges of the signals of the logic device output, etc. can be connected to the output of the logic device. Thus, this device is simpler and possesses a higher reliability in comparison with the known devices. A device for controlling a bridge converter, comprising a clock pulse generator connected to the counting input of the first counter, a second counter, a comparator whose inputs are connected to the supply network, and the output to the first input of the logic unit, which is in order to increase reliability, it is equipped with a key element and /five four eleven L / 7 memory element and the first counter is provided with installation and additional inputs; the output of the first counter is soideii. With the installation input of the second counter and the second input of the logic unit, the output of the second counter is connected to the first input of the memory element and controls the input of the key element whose output connected to the counting input of the second counter, and the input to the output of the pulse clock generator, the comparator output is connected to the additional input of the first counter and to the second input of the memory element, the output of which is below for prison to the third input of the logic block. Sources of information,. taken into account during the examination 1. PI Khristov, TO Todorov Digital control systems for power thyristor converters. M. VELK, 1977, section - b, dokl.38. 2. Japan Patent No. 51-31141,; cl. H 02 M 1/08, 1976. Phagg " I G CH G  I-in hl I one and: