双闭环控制感应加热电源的设计与仿真分析

针对目前20kHz/10kW感应加热电源开关功耗大的缺点,提出了一种基于DSP的容性移相PWM和PFM控制的设计方案。确定以全桥IGBT逆变为主拓扑电路,采用PID和DPLL相结合的双闭环控制策略,对系统进行SIMULINK平台仿真建模。在开环和闭环条件下对仿真结果进行对比分析,实现了负载频率自动跟踪和功率闭环控制。仿真系统到达恒定功率输出的时间为0.2ms,功率因数近似为1,且无周期跳变的现象。改善系统动态特性和稳定控制的同时,验证了该方案的可行性和有效性。

Design and simulation of double-closed loop control for induction heating power

In view of 20 kHz / 10 kW induction heating power, the proposal that a based on DSP capacitive phase-shift PWM and PFM control is presented. Main circuit consists of the three-phase uncontrolled rectifier, the whole bridge IGBT inverter and the series resonant load. In the process of heating, double-closed loop control strategy combined PID (Proportion Integral Differential) with DPLL (Digital Phase Locked Loop) is adopted. Simulation model of induction heating power system is built through SIMULINK platform. The simulation results of the open loop and the closed loop are presented and compared. The load frequency automatic tracking and closed-loop power control are realized. The time to constant power output is 0.2ms. Power factor is approximate to 1. There is no jump phenomenon in the cycle. At the same time, the dynamic performance and stability control of induction heating system are improved. The feasibility and validity of this solution is verified.