Study And Design On The Mediumfrequency Current Supply Of Induction Heating Equipment Based On DSP

This thesis introduces a kind of current supply of the induction heating equipment and itsdesign scheme. The application of the current supply can make the induction heating equipmentfrequency changes more flexible. The function of load frequency following can make theinduction heating equipment work more efficient and save more energy and time.The major parts of the job in this thesis are the design of the current supply integralstructure, the control circuit, the driving and protecting circuit of IGBT.This main circuit of the current supply adopts ACDCACstructure. It contains the rectifier,DC wave filter, inverter, AC filter and insulating transformer.Firstly the 50 Hz AC commercial power is changed into smooth and steady direct current bythe rectifier and wave filter. Then the direct current is changed into AC pulse width modulatedwave by singlephasefullbridgeinverters. Finally the alternating current from the inverterspasses through the LC filter circuit and the insulating transformer, producing the alternatingcurrent required.In the realization of the inverter control circuit, the frequency selffollowingsystem basedon DSP is researched. The core instrument for frequencyfollowingis the PLL. The DSP is usedto realize the realtimecalculation of SPWM drive signal. The hardware control system based onTMS320F240 is designed, which includes sampling circuit, protecting circuit, driving circuit andso on. The program of system is compiled. This thesis makes M57959L to be the core of IGBTdriving module. Three are definite research on the assistant circuits such as the circuits ofrectifier and trigger, the power supply module for control circuit and the detecting part, etc too.