SU760388A1 - Digital device for control of dependent power-diode converter - Google Patents

Description

The invention relates to electrical engineering and can be applied in an industrial DC electric drive.

The closest in technical essence to the invention is a digital device for controlling a valve converter containing a voltage converter into a code, null organs and a digital delay unit generating control pulses for unlocking one-step thyristors of the converter allowing to obtain a linear control characteristic of the output voltage when the angle of control B changes range 180 e. degrees [1].

In such a device, it is impossible to implement the converter control algorithm on fully controlled valves / in which for the period of the supply voltage frequency six unlocking and locking of the valves are performed, which allow to obtain a linear adjustment characteristic of the output voltage from zero to maximum at a small range of control level (30 e degrees). values.

2

The main disadvantage of this device is a low power factor.

The aim of the present invention is to increase the power factor · '

This goal is achieved by the fact that the device is equipped with two reversible counters, two sampling blocks and four elements of condominiums, the input of reversible counters through matching elements and connected to the outputs of the voltage-to-frequency converter 15 and the 15-output counter; The coils are connected via sampling units to the inputs of the pulse distributor.

reversible counters count 20 times of unlocking and locking the converter valves and operate with a shift of 60 el. degrees, which allows using the control algorithm to obtain a linear adjustment characteristic for changing the control angle in the range of 30 el, degrees. '

FIG. 1 shows a diagram of the device; in fig. 2 is the temporary diameter of the device operation; on fig.Z 760388

'characteristic of the converter control algorithm and current 1 _{D of the} phase A valve.

The device contains zero-bodies 1, logical element OR 2, delay block 3 on the counting trigger, coincidence, denia 4, two reversible counters 5, ⁵

elements of coincidence 6, sampling blocks 7, voltage to frequency converter 8 and pulse distributor 9.

In the diagram, reference numeral 10 represented, _n Lena phase A, B and C the supply voltage of the inverter; position 11 clock pulses; position 12 - pulses at the output of the voltage selector to frequency; position 13 shows the 1st 1st reversing counter; in position 15, the second reversing counter reads; position 15 indicates the pulses at the input of the pulse distributor.

FIG. 3 position 16 is indicated by 20 converter control algorithm) position 17 is the current ί _{Α of} phase valve A.

The signals from the outputs of the zero-bodies 1, forming pulses at the moments of transition of the corresponding phases of the supply voltage 25 through zero, arrive at the inputs of the element OR 2, from the output of which the resulting clock pulses, following intervals of 60 electr, go to the input of the digital unit. Reversible counters 5 by appropriate connection of the outputs with the inputs of the sampling units 7 are adjusted to a certain number. The counters are controlled by the elements of coincidence 4 and 6 and the counting trigger of the delay block 3, to the input of which clock pulses arrive.

If there is a potential potential at the inputs by elements of coincidence 4 from the output of the voltage converter to

at frequency 8 impulses are received for addition. When the number N is reached, the sampling unit 7 issues a pulse, and the reversible counter 5 continues counting until the arrival of the clock pulse, which transfers the counting trigger of the delay unit 3 to the opposite state, allowing the subtraction of pulses from the number obtained in the counter when added. When the number N is reached, the sampling unit 7 generates a second pulse.

Reversible meters 5 operate with a shift of 60 email. degrees Both impulses thus obtained are symmetrical with respect to the corresponding synchronization impulse. The first impulse is used for unlocking, the second impulse for locking the corresponding converter valve. The impulse distributor 9 carries out the impulse distribution over the vents. ·

. Change the angle of control about in the range of 30 el. degrees, i.e. symmetrical displacement of the output pulses relative to the zeros of the phase voltage, by changing the pulse repetition frequency at the output of the voltage converter to frequency 8 under the action of the signal and ^ pr · The higher the frequency, the faster the counter 'is filled to the number N and, conversely, a lower frequency leads to a decrease in the angle management.

Such a construction scheme of the device provides a complete overlap of the control range of the output voltage of the converter when changing the control angle in the range of 30 el. degrees

Claims (1)

Claim A digital device for controlling a dependent valve converter containing zero-bodies by the number of phases, connected via the OR element to the input of the first delay unit, a voltage to frequency converter and a pulse distributor, which is in order to increase the power factor, it is equipped with two reversible counters, two sampling blocks and four coincidence elements, with the inputs of the reversible counters connected to the outputs of the voltage-to-frequency converter and ka delay, and the outputs of the reversible counters are connected through the sampling units to the inputs of the pulse distributor.