基于中心抽头变压器的倍频感应加热电源

摘要

A novel multiple-frequency power supply is proposed for high frequency high power induction heating appliances based on center-tapped transformer. Its output frequency is as twice as the device frequency, by using two symmetrical half bridges, sharing two equal resonant capacitances and coupling with center-tapped transformer. Each power switch has zero voltage switch (ZVS) soft switching characteristic, and its conduction time is only a quarter of switching cycle. Thus the power consumption of the switches decrease significantly compared with the traditional inverter. The eight operation modes are analyzed, and the design methods of circuit parameters are also present. Taken IGBT as power switches, a prototype is designed to verify the power supply topology, the theoretical analysis and the circuit parameter selection method.%针对高频大功率应用场合，提出了一种基于中心抽头变压器的倍频式感应加热电源。采用结构对称的两个半桥、共用谐振电容、抽头变压器耦合的方式，使得负载工作频率为功率开关管工作频率的两倍，达到倍频的目的。功率开关管具有软开关特性，且导通时间为其开关周期的25%，相对于传统的桥式逆变器来说，明显降低了开关管的功耗。详细分析了8个不同的工作模式及相应的系统参数关系，给出了电路参数的设计方法。最后以 IGBT 为功率开关管，设计了一台小型样机，通过实验验证了所提出的电源拓扑、理论分析及参数选取方法的正确性。