High power factor soft switching three-phase induction coil synthetic heating power supply

Abstract

The invention provides a high power factor soft switching three-phase induction coil synthetic heating power supply, three groups of single-phase conversion circuits are adopted, each single-phase conversion circuit adopts a single-phase line for voltage input and adopts a single-phase line voltage diode for rectification respectively, a capacitor is not added for filtering, high-frequency alternating current pulse voltage which can enable output envelope lines to be sine waves and adjust the pulse width is formed by conversion through an inverter circuit, the high-frequency alternating current pulse voltage is inputted into three induction coils which are independent mutually and wound in parallel through resonant load matching of three groups of high-frequency transformers to form synthetic magnetic flux, and eddy current is generated in a workpiece which is heated for heating. Inverter bridges adopt the phase shift power control soft switching technology. Sine wave current outputted by the three single-phase inverter bridges are sampled and converted to alternating current voltage signals, the series connection is adopted for connecting the same frequency and the same phase for addition, square wave signals are formed through a zero-crossing comparison circuit, output pulses can track input square waves through a phase-locked loop circuit, three inverter bridge switching tubes are controlled through a power amplification circuit, a pulse distribution circuit and a driving circuit, and the phase-locked frequency tracking synchronization control is realized.

Description

technical field [0001] The invention relates to a heating power supply, in particular to a high power factor soft-switching three-phase induction coil synthesis heating power supply. Background technique [0002] With the development of modern induction heating technology, the application of induction heating in industry is becoming more and more extensive. In some industrial fields such as welding and quenching, the power requirements for induction heating power supplies are getting higher and higher. Coupled with the development of new power electronic devices and the continuous maturity of capacity expansion technology, large capacity and improved power factor have become the development trend of induction heating power supplies. inevitable trend. [0003] At present, the induction heating power supply adopts AC-DC-AC conversion technology. The first step of power input from the power grid is AC-DC conversion, that is, rectification. Rectification includes diode rectifi...

AI Technical Summary

Problems solved by technology

However, high-power power supplies generally use three-phase three-wire input, so there are many problems in improving the power factor.

In addition, the large capacity of the induction heating power supply is currently expanded by connecting multiple switch modules in parallel. There will be problems with current sharing and output power of the drive circuit when multiple modules are connected in parallel, especially at high frequencies.

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