基于移相控制的LLC感应加热电源的研究

Research on LLC Induction Heating Power Supply Based on Phase-shifted Control

为实现串联谐振负载匹配,在电压型串联谐振感应加热电源的基础上,设计了一种适用于大功率高频感应加热的LLC拓扑结构。即在谐振回路中加入匹配电感,通过调整参数达到负载输出功率匹配的目的;采用负载频率跟踪技术与全桥移相脉冲宽度调制PWM功率调节方法相结合的控制方案,根据LLC谐振回路的特性,将输出电压和电容电压相位角作为锁相环控制变量。仿真及实验证明,这种拓扑方法相对于传统的LC串联谐振拓扑,更能满足高频大功率调功应用的需求,且移相控制使逆变器工作在软开关状态,降低了电源在高频工作时的开关损耗。

In order to implement load matching of serial resonance,on the basis of voltage type serial resonant heating power supply,the LLC topology that is suitable for large power and high frequency inductive heating is proposed.The matching inductor is added in resonance loop,and through parameter adjustment to reach load output power matching.In addition,the control strategy combining the technology of load frequency tracking and full bridge phase shift PWM power regulation method is introduced.In accordance with the characteristics of LLC resonant loop,the phase angle of the output voltage and capacitance voltage is used as the control variable for phase lock loop control.Simulation and experiments verify that comparing with traditional LC serial resonant topology,this topology is better to meet the requirements for high frequency large power adjustment;phase-shifted control makes the inverter working in soft switching status,thus the switching loss of the power supply operating under high frequency greatly reduced.