LCL型CPT系统的参数设计方法及频率特性分析

针对 LCL 型电场耦合无线电能传输（capacitive power transfer，CPT）系统现有的参数设计方法运算复杂且计算量大、系统不能运行在软切换状态的问题，提出了一种基于阻抗变换原理的参数设计方法。在此基础上采用频闪映射建模方法和周期不动点理论，求解了使得系统处于零电流切换（zero current switching，ZCS）的软开关频率。分析了耦合机构的等效电容以及负载阻值的变化对 ZCS 频率造成的影响，给出了软开关运行条件下耦合电容和负载的可变化范围。通过仿真与实验验证了系统参数设计方法和软开关频率的准确性，实验样机整体传输效率可达87％。

Parameter design and soft-switching frequency characteristics of capacitive power transfer systems with a LCL resonant circuit

To simplify the complex parameter design process and reduce the switching loss of CPT (capacitive power transfer) system with a LCL resonant circuit, we proposed a simple parameter design method based on impedance transformation principle and presented a calculation method for the soft-switching frequency. With the stroboscopic method and the fixed-point theory, the precise ZCS (zero current switching) soft-switching frequencies can be calculated. The effect of the coupling capacitance and the load resistance on the soft-switching frequency was analyzed, and then the capacitance and the load range allowing the soft-switching were given. A simulation model and an experimental prototype were built to verify the accuracy of the parameter design and the soft-switching frequency. It shows the whole efficiency of the system is about 87%.