SU661710A1 - Converter control device - Google Patents

Description

one

The invention relates to electrical engineering and can be used for three-phase converter control systems.

A device for controlling an inverter is known, which contains a master oscillator, a non-reversible scaling ring, a pre-forming unit, and output pulse shapers. The recalculation ring consists of six input circuits And and three static triggers controlled by separate inputs. Any state of the triggers corresponds to a certain state of the main thyristors of the power circuit. The duration of each of the output signals of the trigger is 180 e. hail, and they are shifted relative to each other by 120 e. hail. one.

A disadvantage of the known device is the complexity and cumbersome of obtaining an adjustable length of the output pulses of the counting ring, especially in the reversible version. It is different from 180 el. hail, the duration of the output pulses is necessary for other power circuits of thyristor converters.

A known inverter control system consisting of a master oscillator.

ring distributor, pulse width driver, output power amplifiers. The ring distributor is a scaling circuit for six, and the output signals have a duration of 180 e. hail, with a shift of 60 e. hail. The main thyristors remove wide pulses directly from the triggers of the ring distributor via power amplifiers. To obtain pulses with a duration of 120 e. degrees, for switching thyristors, coincidence circuits are used in a shaper of duration 2.

A disadvantage of the known inverter control system is the impossibility of obtaining a flexible and simple implementation of changing the duration of broad-thyristor control pulses.

The closest in technical essence and the achieved result to the invention is an inverter control device consisting of a master oscillator, a counting ring in the form of a reversible cable distributor pulse distributor, a preforming unit, output pulse formers 3.

The pulse distributor consists of a binary counter on three J-K triggers, the division into six being carried out by introducing feedback, a forward decoder, a reverse encoder, and a reverse device. The distribution of pulses over the drying channels is verified by means of the decoder on the AND-NOT matching schemes, with the pulse duration of each channel being 60 el. hail, output frequency. Further, the forward or reverse channel pulses, depending on the J-K state of the trigger of the reverse device, pass through the OR circuit on the 2ID-NE elements, are differentiated and amplified in the output shaper are fed to the switching thyristors.

A disadvantage of the known device is the presence of dips on the pulses for the main thyristors, the impossibility of tying up and simply changing the duration of the wide thyristor control pulses depending on the power circuit of the inverter. .

The aim of the invention is to obtain an adjustable length of wide pulses of the counting ring.

For this, a converter control device comprising a series-connected master oscillator and a counting ring, a pre-shaping unit connected to the input of pulse generators is additionally equipped with a series-connected master oscillator, a count ring, a coincidence element, and a phase detector, and the count ring output connected to the input of the coincidence element, the output of which is connected to the input of the preforming unit, the inputs of the phase detector connected to the outputs of the recalculating rings, the output is connected to the input of the additional master oscillator, and the second input of the additional master oscillator is connected to the input of the main master oscillator.

The drawing shows a device for controlling a converter, a block diagram.

It consists of the main master oscillator 1, the main scoring col 2, the additional master oscillator 3, the additional scaling col 4, the phase detector 5, the co-element 6, the pre-shaping unit 7, the output drivers 8.

The voltage Ui applied to the device inputs determines the frequency of the device output pulses, Uz is the width of the wide pulses, the ringing device of which the pulses are formed in block 7 for the main, recharge and switching thyristors to the converter when the device is used to control the inverter thyristors or pulses for power thyristors rectifier.

The device works as follows. The input constant voltage Ui, which is supplied to the input 9 of the main oscillator 1, is converted into a frequency proportional to it. The frequency of the master oscillator is just once the output frequency of the converter.

0 The pulses of the master oscillator 1 are fed to a counting ring O 2, the output of which is obtained in the case of a three-phase power circuit shifted by 120 e. hail, three broad impulses with a duration of 180 e. hail, high frequency, which are removed from the direct outputs of the triggers. The scaling ring usually consists of three J-K triggers and a match point match. In the case of a reversal conversion ring, the matching elements are replaced with AND-OR. Further, with the usual structure of the control system. the inverter, the pulses of the counting ring are fed to block 7, where pulses are generated from them for the main, commuting, and under the charge thyristors. This device employs a phase locked loop system consisting of oscillator 1, oscillator 3, phase detector 5, recalculating rings 2 and 4. The output voltage of phase detector 5, determined by the phase difference of rectifier rings 2 and 4, is supplied to the input of the master oscillator E and adjusts its frequency in accordance with the frequency of the master oscillator 1. In the synchronous mode, the system establishes a constant phase difference between the oscillator signals at a constant average value of the output voltage detector 5. The phase difference and the magnitude of the output voltage of the phase detector 5 depend on the magnitude and sign of the initial detuning on the frequency of the generators 1 and 3. The frequency stability of the output pulses is determined by the frequency stability of the generator 1, and therefore the generator 3 may be of low stability and, therefore performed by a simpler scheme. Since the driving oscillator 3 is influenced by the control Ui, the three-phase voltage of the recalculating ring 4 shifts in phase relative to the recalculating ring 2. The shift range here is from 0 to 180 el. hail

Q symmetry between pulses inside each scaling ring. A change in the input voltage Ui causes a change in the frequencies of the master oscillators 1 and 3. By varying the voltage Uz, the phase between the three-phase voltages ae5 of the alternating rings 2 and 4 with a duration of 180 e. Degrees, the output frequency is regulated. These are phase shifted by voltage Us. pulses of recalculating rings 2 and 4 of a phase are applied to the inputs of the matching element 6. As a result, at the output of element 6, a system of three-phase voltages with a variable voltage Ui duration is obtained. The duration of these three-phase voltages can be set smoothly in the range from 0 to 180 e. hail.

In the case of reversible recalculated rings 2 and 4, the foregoing remains valid. Next, broad three-phase pulses, generated in duration, arrive at the preforming unit 7, where they form control pulses for the main, commuting, and recharge thyristors. Reinforced by the output shaper 8, they are sent to thyristors. All the above is true for any converter, including autonomous and dependent inverters, for rectifiers.

The device for controlling the converter makes it easy to change the wide pulse duration of any converter through the use of a phase-locked loop system in the additional oscillator, the scaling ring, the phase detector and the coincidence element.

Claims (3)

1. Kalashnikov B. Ye., Krivitsky S. O., Enshtein I. I., Inverter control systems, M., Energia, 1974. p. 91. 25 2. Report of LIIZT, 1971, L., Development of an asynchronous drive for an AC electric train with regenerative braking. 3. Technical report No. 73025704, ОАЮ 120424.ИОВ NIIEM, 1973. To thyristors