基于DSP的逆变电源锁相环的设计与研究

Research and Design of PLL Based on DSP in HF-Inverter

采用基于DSP的数字锁相环(DPLL)对高频逆变电源输出频率的实时控制,可实现逆变器工作频率对负载谐振频率的同步跟踪,确保逆变器开关器件工作在零电压电流软开关(ZVZCS)状态,显著减小功率器件的开关损耗和提高装置效率。文中在给出DSP控制的逆变电源拓扑结构基础上,推出了适用于高频逆变电源的锁相环数学模型,在Z域中对二阶数字锁相环进行了稳定性分析和动态设计。在对锁相环Z域传递函数分析的基础上,得出二阶数字锁相环的稳定条件,并给出数字锁相环的软件实现,最后进行了实验验证。实验结果表明在Z域中对基于DSP的二阶数字锁相环的动态分析和设计是合理可行的。用此方法设计的电源具有良好的动态响应和抗扰性能。

The Digital Phase- Locked Loop（DPLL）technology based on a Digital Signal Processor （DSP） is applied to control the operating frequency of an High-Frequency-Inverter （HF- Inverter） simultaneously, so as to adapt varieties of the load resonant frequency to keep the inverter always working on ZVZCS （Zero Vohagc-Zero Current Switching） mode. At the meanwhile, the losses of switching components are reduced obviously and the efficiency of the power is improved greatly on ZVZCS mode. In this paper, the topology of HF- Inverter based on DSP is presented, and PLL＇s mathematic model is set up, which is suitable for HF- Inverter. The stability of second order DPLL is analyzed, and the dynamic design is considered using the Z-transform technique. At the base of analyzing the Z- transfer function of DPLL, the stability condition of second order DPLL is presented. The software of the DPLL is given, and the corresponding experiment is done finally. The results of experiments show that the dynamic analysis and design of second order DPLL are reasonable and feasible. The power designed by this method has good dynamic response and noise immunity.