Phase sequence self-adaption trigger circuit of three-phase fully-controlled rectifier induction heating power supply

Abstract

The invention belongs to the field of electrical technology and discloses a phase sequence self-adaption trigger circuit of a three-phase fully-controlled rectifier induction heating power supply. The phase sequence self-adaption trigger circuit is connected in series between a three-phase alternate current and a three-phase full-bridge thyristor drive axle and mainly comprises a phase sequence judging circuit, a three-phase synchronous signal additional phase shifting and phase sequence gating circuit, a thyristor three-phase trigger pulse phase shifting circuit and a three-phase trigger phase gating and output circuit. After a three-phase switching-in phase sequence of the induction heating power supply is judged by the phase sequence judging circuit, a suitable three-phase rectifier trigger pulse is generated by the three-phase synchronous signal additional phase shifting and phase sequence gating circuit and is sent into the thyristor three-phase trigger pulse phase shifting circuit to generate phase shifting; and the three-phase rectifier trigger pulse which is subjected to phase shifting is sent to the three-phase trigger phase gating and output circuit to drive a thyristor of the three-phase full-bridge thyristor drive axle. According to the invention, the random switching-in of a line sequence of three phases of the induction heating power supply is implemented and the phase sequence self-adaption trigger circuit has the characteristics of simple structure and low cost.

Description

technical field [0001] The invention belongs to the field of electrical technology, and relates to a start-up technology of an induction heating power supply, in particular to a phase sequence adaptive trigger circuit of a three-phase full-control rectification induction heating power supply. Background technique [0002] At present, induction heating is widely used in smelting, diathermy, quenching and other fields due to its advantages of high heating efficiency, fast temperature rise, and good controllability. Induction heating power supply is one of its key equipment. In the induction heating power supply, the main circuit uses 380V three-phase AC to send to the thyristor SCR, and then performs three-phase full-bridge controllable rectification to output 0~500V DC voltage. The trigger pulse of the thyristor SCR needs to be introduced after △-Y conversion from the three-phase synchronous transformer. Then the power supply requires that the line sequence of the three-phas...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the three-phase phase sequence of the traditional induction heating power supply cannot be connected at will, and propose a phase sequence adaptive trigger circu...

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