Researchondigital IGBT Three-phase Synthesis Multiple-frequency Induction Heating Power Supply

This paper, based on three-phase synthesis digital frequency induction heating power supply as the research object, briefly introduced the development and the basic theory of the induction heating. For high-frequency and great-power requirements, this paper research on 180KHz/300KW high frequency induction heating power supply, using three single-phase synthesis of three-phase diode rectifier is not controlled directly without filtering plusharmonic-type inverter circuit, which is controlled to achieve the purpose of unit power factor.Based on the power modulation strategies analasys of PDM and PSPWM, Time-sharing-PDM&PSPWM is presented, and its working principle is analysised.This paper used IGBT in parallel time-control theory to add output frequence. In order to raise output power, Synthesis power chose the way of primary parallel and second series of transformer. Every part in main circuit is designed. And the control and protection circuit based on TMS320F2812DSP and high-speed chip CPLD is detailed analysised. Setting up a sample of 180KHz/300KW, the microcontroller DSP realized all digital power control, and CPLD realized digital phase-locked and frequency division control. This control method can in real time and automatically track the load resonant frequency. Based on the the theoretical analysis, giving simulation analysis and key waveforms for single-phase inverter main circuit equivalent structure and control methods by PSPICE simulation software. The experimental proves the new power regulating strategy available.