基于E类放大器的新型无线电能传输控制策略

E类放大器是磁共振无线电能传输(wireless power transmission,WPT)系统中常用的高频电源,其开关效率是评价WPT系统整体性能的关键指标.针对E类放大器中开关器件的效率和电压应力与负载的紧耦合关系导致其输出效率的不稳定,根据锂离子电池的充电特性和E类放大器的输出效率特性,选用合理的谐振补偿网络结构,提出了一种通过电容和电感阵列实现E类放大器零电压开关状态的主动控制策略.结果表明:在20 cm气隙条件下实现了功率输出为1.1 kW、逆变部分效率高于95％以上的WPT系统实验,大大提高了采用E类放大器的WPT系统的稳定性,验证了所提出控制策略的有效性.

Research on Control Strategy of Wireless Power Transmission Based on Class E Amplifiers

Class E amplifiers is a commonly used high-frequency power supply in wireless power transmission (WPT) system, and their switching efficiency is a key indicator for evaluating the overall performance of the WPT system. The output efficiency of class E amplifier is unstable due to the close coupling relationship between the efficiency, voltage stress of switching devices and the system load. In this paper, the output efficiency of class E amplifier and the charging characteristics of lithium-ion battery are considered together, an active control strategy is proposed to realize zero voltage switching of class E amplifier through adding an capacitor and inductor array to the compensation network of WPT system. Under the condition of a 20cm air gap, a WPT system experiment with a power output of 1.1kW and an inverter efficiency higher than 93% was realized, and the effectiveness of the proposed control strategy with class E amplifiers was verified.