RU2011273C1 - Device for control of adjustable ac voltage-to-ac voltage converter - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: device has control angle set-point device 16, sync pulse shaper 2, whose input is intended for connection of converter input voltage to power mains 9, master oscillator 1, whose output is connected to the inverting input of counter 3, whose output is connected to the first input of comparison circuit 4, amplifier-shaper 7 of converter rectifier control pulses and computing unit 5, 6 with storage of the output signal equal to the product of the signal at the first input of the computing unit by the ratio of the signal at the second input of the computing unit to the maximum probable signal at the output of the set-point device connected to the second input of the computing unit, whose first input is connected to the output of the counter, whose reset input is connected to the first output of the sync pulse shaper, whose second output is connected to the clock input of the computing unit, whose output is connected to the second input of the comparison circuit, whose output is connected to input of the amplifier-shaper. EFFECT: facilitated procedure. 2 dwg

Description

 The invention relates to electrical engineering and can be used in devices of phase-pulse control by alternating voltage.

 Known devices for phase-pulse control of the thyristor regulator 11, 21. The devices include a clock driver, which starts the block delay pulses, the delay value of which is determined by the control signal from the output of the master.

 The disadvantage of this device is that disturbances significantly affect the accuracy of voltage regulation.

 A device is known that forms an angle of inclusion by a thyristor for controlling the magnitude of an alternating voltage. The device forms the angle of inclusion of the thyristors at the moment of equality of the digital reference signal and the digital signal from the output of the pulse counter of the uncontrolled frequency generator.

 The accuracy of voltage regulation is significantly affected by external and internal factors. External disturbing factors include frequency deviations of the ac mains voltage. The internal disturbing factors include the instability of the pulse frequency of the generator included in the pulse delay device. The reason for this may be a spread in the parameters of its constituent elements under the influence of ambient temperature or internal transients.

 The purpose of the invention is to increase the accuracy of voltage regulation by a phase-shifting device by eliminating the influence on the accuracy of disturbing influences (their compensation).

 The essence of the invention lies in the fact that the device containing the adjusting angle adjuster, a synchronizing pulse generator, the input of which is designed to connect the input voltage of the converter to the network, the master oscillator, the output of which is connected to the counter input of the counter, the output of which is connected to the first input of the comparison circuit and an amplifier-driver of impulses for controlling the valves of the converter; an additional computing unit with storing the output signal equal to the product of the signal n the first input of the computing unit on the ratio of the signal at the second input of the computing unit to the maximum possible signal at the output of the setter connected to the second input of the computing unit, the first input of which is connected to the output of the counter, the reset input of which is connected to the first output of the generator of synchronizing pulses, the second output of which is connected with such an input of the computing unit, the output of which is connected to the second input of the comparison circuit, the output of which is connected to the input of the amplifier-former. In total, the introduced elements make it possible to calculate how many pulses per one half-cycle will come from the output of the frequency generator to the counter input and multiply this number by the ratio of the control signal to the maximum possible control signal. The calculation result is compared with the current output signal of the counter and its value will not depend only on the control code from the output of the setter, but will also be proportional to the frequency of the voltage generator and inversely proportional to the frequency of the mains voltage. The turn-on angle of the thyristor will be determined by the ratio between the reference code and the maximum possible control code and not depend on the frequency of the mains voltage and the frequency generator. Thus, the accuracy of controlling the angle of inclusion of the thyristor increases. The inventive device provides a strict relationship between the input control signal and the magnitude of the opening angle of the thyristor. The influence of interference associated with external influences on the device or internal changes in the parameters of the elements is reduced.

 In FIG. 1 shows a structural diagram of the inventive device; in FIG. 2 - diagrams of the output signals of the elements included in the device.

 The output of the frequency generator 1 is connected to the first input (counting) of the counter 3. The network voltage is supplied to the input of the clock generator 2, one of the outputs of which is connected to the clock input of the reset counter 3, and the second output goes to the clock input of the computing unit 5, storing the output signal 6. The output of the counter 3 goes to the inputs of the computing unit 5 and to the input of the comparison circuit 4. The output of the adjusting angle adjuster 16 is connected to the third input of the computing unit 5. The output of the memory element 6 is a calculator th block 5 is connected to B input of the comparator circuit 4, the output of which through the amplifier driver 7 is connected to the control input 8 of the valve.

 Frequency generator 1 delivers pulses whose frequency determines the accuracy of regulation, the higher the frequency, the greater the accuracy.

 The clock generator 2 generates zero voltage signals 11 at its input, and the signal 14 is ahead of the zero signal for a while. The duration is determined by the speed of the calculation unit 5 and the memory device.

 The pulse counter 3 clock signal 13 is restored to its original state (zero), after which the counting of pulses arriving at the counting input begins. The result of the count in binary code is fed to the output: to the input of the computing unit 5 and to the input of the comparison circuit.

где U₃ - сигнал с выхода счетчика 3;
U₁₆ - сигнал с выхода задатчика угла регулирования 16;
U_{180 эл.гр}. - сигнал угла регулирования 180 эл. град.The computing unit 5 at the time of receipt of the synchronization signal 14 multiplies the digital signal from the output of the adjuster of the angle of regulation 16 by the output signal from the output of the counter 3 and divides the result by a signal to set the angle of 180 el. hail. according to the formula
U ₅ =

where U ₃ is the signal from the output of counter 3;
U ₁₆ - signal from the output of the adjuster of the angle of regulation 16;
U _{180 electric gr} . - a signal of an angle of regulation of 180 el. hail.

 The result of the calculation is fixed by the memory element 6 until the next calculation. The comparison circuit 4 compares the current signal from the counter with the signal stored in the memory device, and when they match, generates a single pulse at the output. The driver amplifier amplifies the pulse control pulse in magnitude and duration.

 For the technical implementation of blocks (3, 4, 5, 6), you can use the K1816 chip. The frequency block can be obtained at the output of the K 531GG1 chip. The block for generating synchronizing signals can be performed according to the scheme 3.77 (p. 172 141) and the K155AG1 multivibrator in standby mode. The galvanic isolation and amplification of the signal from the output of the comparison circuit can be carried out using an optocoupler.

 A semiconductor valve key when a control pulse is received on it commutes the load to the network.

 The inventive device in each control cycle counts the number of pulses from the generator during one half-cycle of the mains voltage. After which, the computing unit 5 calculates the number of pulses received from the output of the generator during a given angle of turn-on (delay) of the thyristor and compares it with the current value of the counter throughout the entire subsequent half-cycle by storing the result of the calculation in a memory element.

 Thus, the goal is achieved, the error in the regulation of the thyristor turning angle is reduced, which arises due to the instability of the frequency of the pulse generator and the frequency of the mains voltage. The inventive device is automatically adjusted when the voltage of the network, its frequency, and when the frequency of the frequency generator changes. The economic effect is achieved by increasing the accuracy, stability and versatility of the device. (56) Copyright certificate of the USSR N 1508320, cl. H 02 M 1/08, 1989.

 USSR author's certificate N 1429752, cl. H 02 M 1/08, 1988.

 USSR author's certificate N 1020937, cl. H 02 M 1/08, 1985.

Claims (1)

 DEVICE FOR CONTROLLING A REGULATED AC VOLTAGE CONVERTER TO AC VARIABLE and an amplifier-driver of impulses for controlling the valves of the converter, characterized in that a computing unit with memory signal equal to the product of the signal at the first input of the computing unit by the ratio of the signal at the second input of the computing unit to the maximum possible signal at the output of the setter connected to the second input of the computing unit, the first input of which is connected to the output of the counter, the reset input of which is connected to the first output of the shaper synchronizing pulses, the second output of which is connected to the clock input of the computing unit, the output of which is connected to the second input of the comparison circuit, the output of which is connected with the input of the amplifier-shaper.

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