一种利用可切换补偿电容的三线圈无线电能传输系统互感识别及效率优化方法

A Mutual Inductance Identification and Efficiency Optimization Method for the Three-coil Wireless Power Transfer System by Utilizing Switchable Compensation Capacitor

为实现三线圈无线电能传输(wireless power transfer,WPT)系统负载位置变化时线圈间耦合互感包括交叉耦合互感在内的有效识别,文中提出一种利用可切换补偿电容实现三线圈WPT系统线圈间互感识别的方法。文中首先基于互感耦合模型,建立采用可切换中继补偿电容的三线圈WPT系统数学模型,分析补偿电容切换前后的系统输入阻抗与线圈间互感的关系,得到三线圈WPT系统耦合互感的识别方法;其次分析中继线圈补偿电容值与线圈间能量传输效率的关系,得到三线圈WPT系统线圈系统效率的优化策略,并给出详细的容值优化方法;最后,搭建实验平台对理论分析进行验证,实验结果显示,所提出的三线圈WPT系统各线圈间互感识别精度平均可达96%,线圈系统效率提升最高可达3.16%。证明了所提出的利用可切换补偿电容的三线圈WPT系统互感识别方法及线圈系统效率提升方法的有效性。

In order to effectively identify the mutual inductances including cross-coupled mutual inductance of the three-coil wireless power transfer(WPT) system when the load position varies, this paper proposed a method to identify the mutual inductances of the three-coil WPT system by adopting a switchable compensation capacitor. Firstly, the mathematical model of the three-coil WPT system with a switchable relay compensation capacitor was established. The relationship between mutual inductance and input impedance of the system before and after switching the relay compensation capacitor was studied, and the mutual inductance identification method was derived. Subsequently, the relationship between coil-to-coil efficiency and relay compensation capacitance was analyzed, and the optimization method of coil-to-coil efficiency was derived. The detailed compensation capacitance optimization method was also presented. At last, an experimental setup was built up to validate the theoretical analysis. The experimental results show that the identification accuracy of the mutual inductances among the three coils could reach 96%,averagely, and the maximum coil-to-coil efficiency improvement is 3.16%, proving effectiveness and accuracy of the mutual inductance identification method and the coil-to-coil efficiency improvement method for the three-coil WPT system by utilizing the switchable compensation capacitor.