感应耦合电能传输系统的移相与脉冲密度混合电压调控策略

针对感应式无线电能传输系统中高频逆变器效率和负载电压无级调节的两个关键问题，提出一种移相脉宽调制(PSPWM)和脉冲密度调制(PDM)兼用的混合调制方法，其中，变流器主频率一定、开关处于电压软开关状态，有选择地对PDM中某一脉冲实施移相处理，并利用脉冲密度数和移相角大小调节输出电压和功率，实现变流器的高效率运行和输出电压平滑稳定调节。通过实验，对上述PDM和PSPWM与所提出的混合调制方式的负载输出电压平滑性与逆变器效率进行了对比分析，所提出的混合调制方式在实现无级调压的情况下纹波系数较PDM减少了9%、逆变器的损耗相对于PSPWM减小了5%~20%。

Hybrid Strategy of Voltage Regulation Combined Phase-shift and Pulse Density Modulation Methods for Inductively Coupled Power Transfer System

Efficiency of high-frequency inverter and stepless voltage regulation are two essential issues in inductively coupled power transfer system. A hybrid modulation method is proposed, which combines phase-shift pulse width modulation(PSPWM)and pulse density modulation(PDM). In this method, the inverter frequency is constant and the power switch is in zero voltage switch(ZVS)state. To keep the efficient operation of the converter and adjust output voltage steplessly, a certain pulse in PDM is selected to process phase-shift control, and output voltage and power are adjusted by changing both the number of tuning pulse and phase shift angle. The smoothness of output voltage and the inverter efficiency of PDM, PSPWM and the proposed hybrid modulation method are compared and analyzed through an experimental prototype. Compared with PDM, the ripple coefficient is reduced by 9% in the case of stepless voltage regulation, and the loss of inverter is reduced by 5%~20% with respect to the PSPWM.