350kHz Frequency-type IGBT Time-Sharing-Density Control Series Resonant Inverter

At present,the frequence of the domestic solid-state induction heating power that is higher than 100kHz are basically using MOSFET.Because the capacity of MOSFET is small, high-power devices require many in parallel and in order to eliminate the inherent parasitic diode reverse recovery characteristics of the negative, we must use quickly restore diodes in series. The reliability and efficiency are reduced by using many devices. While the capacity of IGBT is much higher than the MOSFET,and diode parasitic problem does not exist in high-power devices.However, the IGBT switching losses is large, especially at high-frequency switch with tail current ,this limits the frequency improvement of IGBT ,At present, the switching frequency of IGBT can status at 100kHz at zero current switching (ZCS).In this paper,by studying of high frequency induction heating power , using frequency-based circuit structure of the main inverter circuit, IGBT parallel time - pulse density of a composite control strategy,reach switching frequency of 350kHz, including his irritable start circuit design, frequency tracking circuit design, voltage and current detection and driving circuit design,the study of time-sharing based on the CPLD (Complex Programmable Logic Device)+DSP(Digital Signal Processing)pulse density regulation of the implementation of control strategies, software simulation and the download test,used Matlab simulation for system . A induction heating power of 1KW/350kHz was designed for experiment,and the results are gived.