并联谐振感应加热电源控制技术的研究

Research on Control Technique of Parallel Resonant Induction Heating Power Supply

针对感应加热过程中负载谐振频率不断变化的问题以及功率调节的需要,通过对并联谐振逆变器的工作原理进行分析,提出了一种并联谐振感应加热电源中直流软斩波功率调节与定角锁相环频率跟踪的控制方法,并对控制电路进行了设计。该控制技术使逆变器开关管一直工作在ZVS状态,降低了功率器件的开关损耗,提高了中频加热的工作效率,使系统的电磁干扰和电磁兼容性能得到改善,让逆变电路始终工作在小容性状态。

The load resonant frequency constantly changes and the power needs to be regulated in the process of induction heating.After making analysis of the working principle of parallel resonance converter,the paper puts forward the control method of regulating DC soft chopper and tracking the fixed-angle phase-locked loop frequency of the parallel resonant induction heating power supply,and designs the control circuit This control technique can make the inverter switching tube keeping working under the ZVS state,which decreases the switching loss of power devices and increases work efficiency of the medium frequency induction heating to improve electromagnetic interference and EMC performance and make inverter circuit keeping working under the small capacitive current state.