SU1246291A2 - Device for controlling thyristor rectifier - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used in control systems with controlled thyristor rectifiers. The purpose of the invention is to improve the quality of the output voltage by suppressing low-frequency harmonics. The device contains three consecutive circuits, the first of which consists of a current magnitude setpoint 1, a current regulator 2, a pulse phase control unit (BIFU) 3, a thyristor rectifier 4, the output of which is connected to the load 6 via a current sensor 5. and a third of the circuit includes an input multiplier 9 (10), a sample storage element 11 (12), to the free input of which a pulse shaper 13 (14) is connected, an astatic regulator 15 (16), to a free input of which one of the outputs is connected low frequency harmonic level adjuster 17 and output O) to 4 Od 1C UD

Description

a multiplier 18 (.19) connected to one of the inputs of the adder 20. A voltage sensor 7 is connected between the load 6 and the inputs of the multipliers 9 10. The generator of the orthogonal functions 8 is connected to the input by the input (its network, and the outputs to the inputs of the multipliers 9, Yu , pulse formers 13, 14, and multipliers 18, 19. The output of sumator 20 is connected to the free input of the FIFA Zo. The introduction of the static regulators 15 ,, 16 and the level indicator in a low hour.

I

The invention relates to electrical engineering, can be used in control systems with controlled thyristor rectifiers, and is an improvement of the device according to the author, 1069120.

The purpose of the invention is to increase the quality of the output voltage by suppressing the low-frequency 1 armonic

- On; etertezh presents the block diagram of the proposed device.

The device contains a current setting unit 1, a current regulator 2, a pulsed-phase control unit 3 of a clockwise rectifier 4, a sensor 5 that is KHj load 6, a voltage sensor 7, a generator 8 of orthogonal functions, input multipliers 9 and 10, elements 11 and 12 sampling-storage, shapers 13 and 14 pulses, astatic regulators 15 and 16, low-frequency harmonic level suppressor 17 Uo, / twc-input multipliers 18 p 19, adder 20, Unit output 1 of the current magnitude sub-circuit to the input current regulator 2, the second input of which is connected to the ELI stroke of current sensor 5. The output of current regulator 2 is connected to the input of the unit 3 of phase-phase control, the second input of which is connected to the output of summer 20; and the output to the input of the thyristor voltage of the capacitor 4 ,,, the outputs of which are connected to the inputs, loads 6, current sensors 5 and voltage 7. The first inputs of multipliers 9 and 10 are connected to the output of voltage sensor 7, and the outputs to the information inputs of sample-and-hold elements 1 and 12, the outputs of which are connected to the nepBtiM inputs

This harmonics 17 allows the automatic axis to maintain a zero difference between the set low-frequency harmonic level and the output signals of the sample-storage elements 11, 12. All changes in the - and non-canonical harmonics at the output of the rectifier 4 are compensated by changing the magnitude of the compensating signal U. The elimination of the effect of changes in the frequency of the mains supply is carried out by synchronizing the generator 8. 1 Il.

- 0 0 5

Controllers 15 and 16. The second inputs of the static controllers 15 and 16 are connected to the outputs of the low-frequency harmonic level adjuster 17, and the outputs to the first inputs of the second multipliers 18 and 19, The second inputs of the multipliers 9,10, 18 and 19 and the inputs of the formers 13 and 14 pulses, the outputs of which are connected to the control inputs of elements 11 and 12 of the sample-storage, are connected to the outputs of the generator 8 orthogonal functions, the synchronizing input of which is connected to the network supplying the thyristor rectifier 4. The outputs of the multipliers 18 and 19 are connected to the inputs adder 20.

The device works as follows:.

.An input to current regulator 2 is supplied to the setpoint generator 1 of the current magnitude and the feedback signal from the current sensor 5. The output signal of the current regulator 2 through the block 3 of the pulse-phase control affects the thyristor rectifier 4, the output signal of the voltage sensor 7 carrying low-frequency harmonic information UJ is multiplied by multipliers 9 and 10 with O orthogonal functions U si.n UJ t, and cos U) t .. Elements 11 and 12 of the sample-storage, controlled by the imprinter 13 and 14, compute the average values of the output signals of the snipers 9 and 10 for the period of orthogonal functions in accordance with expressions

wt

a, --- Ud (u) t) cos totdcJt; 1 u) T -I

DT

bs - --- Ud (ut)) t u) T

And they remember their values — for a time equal to the period of the orthogonal function. The magnitudes of the output signals a and b of the elements 11 and 12 of the sample-storage depend on the amplitude and phase of the low-frequency harmonic and. The static regulators 15 and 16 automatically maintain the zero difference between the set low-frequency harmonic level from the output of the low-frequency non-canonical harmonic level setpoint generator 17 and the a and b output signals of the sampling-storage elements 11 and 12.

An increase in the initial level of non-canonical harmonics at the output of the thyristor A, caused, for example, by an increase in the asymmetry of the supply network or a decrease in the transfer coefficient of the thyristor rectifier when the control angle changes, causes an increase in the output signals a and c. ki-hr aneni. An increase in the output signals of the sampling-storage elements 11 and 12 disturbs their correspondence to the low-harmonic level signal of the sensor 17, which leads to the appearance of error signals at the inputs of the static regulators 15 and 16. The error signals increase the output signals of the static regulators 15 and 16, the multiplication of which by multipliers 18 and 19 by the input signals of the generator 8 of orthogonal functions, followed by summation by the adder 20 of the output signals of the multipliers 18 and 19 increases the com

Redator V. Petrash Order 4017/52

Compiled by A.Pridatkov

Tehred V. Kadar Corrector-E. Sirohman

Circulation 631 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

“Production and printing company, Uzhgorod, Projecto st., 4

j you f5

0 5

0

five

the paging signal U. Under the action of an increase in the compensating signal and entering the input of the unit 3 by impulse-phase control, there is a decrease in -and non-canonical harmonics at the output of the thyristor rectifier 4.

Thus, any changes in the non-canonical harmonics at the output of the thyristor rectifier are compensated by changing the value of the compensating signal V. The values of the non-canonical harmonics are automatically maintained at the level specified by the value of the low-frequency harmonic level setting signal 17. To eliminate the effect of varying the frequency of the mains supply on the effect of suppressing the low-frequency harmonics, the generator of 8 orthogonal functions of the thyristor rectifier supplying network is synchronized.

Claims (1)

Invention Formula A device for controlling a thyristor rectifier according to aut. St. No. 1069120, in order to improve the quality of the output voltage by suppressing the low-frequency harmonics, it is equipped with two astatic regulators and a low-frequency harmonic level adjuster, the first inputs of the static regulators being connected to the outputs of the sample-store elements, the second inputs to the outputs of the low-frequency harmonic level adjuster, and the outputs of the static controllers to the first inputs of the second multipliers.