To charge the battery of electric vehicles (EVs), inductive power transfer (IPT) system has been considered to be more appropriate than traditional plug-in system especially for its security and convenience. This study proposes a hybrid IPT system for EVs charging applications adopting one transmitter coil with series compensation and two receiver coils with series compensation and LCL compensation. With the help of the two receiver coils and proper parameters design, the proposed system can naturally obtain constant current (CC) and constant voltage (CV) outputs and the maximum output power can be naturally limited which can prevent the system from possible overload. Therefore, the reliability of the proposed system is increased. Since the mode switching process can be automatically realised according to the value of battery equivalent load without extra control strategy and circuit, the fixed-frequency control can be used. Therefore, not only zero phase angle condition, but also the soft switching can be achieved. The theoretical analysis is presented with the design process of the IPT coils and resonance parameters for required battery charging profile. The performance of the system is verified by a 3.3 kW experimental prototype. The experimental results coincide well with the theoretical analysis.

中文翻译：

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具有自然CC–CV输出特性的混合IPT系统，用于EV电池充电应用

为了给电动汽车（EV）的电池充电，特别是出于安全性和方便性的考虑，感应功率传输（IPT）系统比传统的插入式系统更为合适。本研究提出了一种用于电动汽车充电应用的混合IPT系统，该系统采用一个带有串联补偿的发射器线圈和两个带有串联补偿和LCL补偿的接收器线圈。借助于两个接收器线圈和适当的参数设计，所提出的系统可以自然地获得恒定电流（CC）和恒定电压（CV）输出，并且可以自然地限制最大输出功率，这可以防止系统可能出现过载。因此，提高了所提出系统的可靠性。由于可以根据电池等效负载的值自动实现模式切换过程，而无需额外的控制策略和电路，因此可以使用固定频率控制。因此，不仅可以实现零相位角条件，还可以实现软切换。针对IPT线圈的设计过程和所需电池充电曲线的谐振参数，进行了理论分析。该系统的性能已通过3.3 kW的实验原型验证。实验结果与理论分析相吻合。针对IPT线圈的设计过程和所需电池充电曲线的谐振参数，进行了理论分析。该系统的性能已通过3.3 kW的实验原型验证。实验结果与理论分析相吻合。针对IPT线圈的设计过程和所需电池充电曲线的谐振参数，进行了理论分析。该系统的性能已通过3.3 kW的实验原型验证。实验结果与理论分析相吻合。