Current sharing circuit and method of thyristor alternating-current switch parallel circuit

Abstract

The invention discloses a current sharing circuit and method of a thyristor alternating-current switch parallel circuit, the parallel circuit comprises N branches connected in parallel, N is a positive integer greater than 1, a group of antiparallel thyristors is connected between the input and the output of each branch, the current sharing circuit comprises N mutual inductors corresponding to theN branches, a driving unit, a voltage detection unit, a demagnetization detection circuit and a control circuit, the primary side of each mutual inductor is connected to one corresponding branch in series, the secondary sides of the N mutual inductors are connected in series, and the control circuit is used for determining a thyristor to be driven during current commutation according to the voltage drop detected by the voltage detection unit. and after the demagnetization detection circuit detects that the N mutual inductors are demagnetized, the driving unit is controlled to drive the determined thyristors to be conducted, so that the problem of iron core magnetic reset of the mutual inductors in each working period is solved, and relatively high cost effectiveness and a good current sharing effect are achieved.

Description

technical field [0001] The invention relates to the technical field of current control for parallel operation of thyristors, in particular to a current equalizing circuit and method for parallel circuits of thyristor AC switches. Background technique [0002] Thyristors (SCRs) are usually used as semi-controllable components and have a wide range of applications. The more common application is to use two SCRs in anti-parallel connection (or a bidirectional SCR) as a solid-state AC switch, which is commonly used in UPS, STS, etc. It is used as a quick switch (AC Switch) in the device. Usually, in order to achieve a higher current level, it is necessary to use more devices in parallel (for example, a large current value that cannot be achieved by a single device, or multiple small devices in parallel to reduce costs, or for other special purposes). At present, the characteristics of SCR are negative temperature characteristics, the voltage drop under each temperature conditio...

AI Technical Summary

Problems solved by technology

The obvious disadvantages of the current sharing reactor are: large volume, serious heat generation, and high cost. It is difficult to realize when the current is high, and there is a risk of overcurrent saturation.

[0007] For this reason, the present invention aims to solve the deficiency of the transformer iron core saturation that is used for current sharing above

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