串联谐振高频逆变电源的数字锁相研究

Research on Load Series-resonant HF-Inverter Power Based on DPLL

为提高串联谐振式逆变器的输出效率,减小装置功率器件的开关损耗,确保功率器件的零电流开关(ZCS)模式,必须控制逆变器的工作频率始终与负载的谐振频率保持同步。本文针对传统模拟锁相环的缺点,采用基于DSP的数字锁相环(DPLL)对高频逆变电源的工作频率实时控制,使之同步跟踪负载的谐振。通过建立逆变电源锁相环的数学模型,在Z域中对二阶数字锁相环进行稳定性分析和动态设计,给出锁相环的稳定条件。在MATLAB环境下,对DPLL及逆变电源进行了仿真验证。结果表明:数字锁相环的动态分析和设计是合理可行的,用此方法设计的逆变电源具有良好的频率跟踪特性,实现了ZCS软开关。

In order to improve the efficiency of the power and reduce the losses of switching components, the operating frequency of the inverter power is controlled, so as to track the load resonant frequency simultaneously to keep the inverter always operating in Zero - Current - Switching （ZCS） mode. As a result of the shortcoming of traditional simulate Phase - Locked Loop , in this paper , the Digital Phase - Locked Loop（ DPLL） technology based on DSP is applied to control the operating frequency of an HF- Inverter power simultaneously to track the load resonant frequency. By setting up the mathematic model of the invert power, the stability analysis and dynamic design of the second - order DPLL is completed in the Z - plane. From the above stability analysis, the condition stabilizing DPLL is observed. Finally, both models of the inverter power and the DPLL are constructed and simulated in MATLAB environment. The results of simulation show that the dynamic analysis and design of the second- order DPLL controller is reasonable and feasible, also it indicates that the HF- Inverter power using the DPLL technique has good characteristic of frequency tracking to keep the inverter always operating in ZCS mode.