Wireless charging has become increasingly popular for electric vehicles (EVs) in recent years. However, possible device damage may happen because of the sharp variations of inverter output current and the ZVS angle due to the alignment variation between resonant coils especially while charging. To design a protection strategy, the characters of the inverter output current and phase angle are analyzed when the wireless charging EV leaves. The protection strategy is composed of the insufficient angle protection, overcurrent protection, and the excessive angle protection. A detection circuit is designed to measure the variation of inverter output current and phase angle. A wireless charging EV prototype is established to validate the proposed methods. The experimental results show that the designed detection circuit and protection strategy can catch the abnormal working state of the system when the wireless charged EV leaves and take measures immediately to protect the main circuit of the system from device damages.

中文翻译：

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无线充电电动汽车的保护策略

近年来，无线充电在电动汽车 (EV) 中变得越来越流行。然而，由于谐振线圈之间的对齐变化，尤其是在充电时，逆变器输出电流和 ZVS 角的急剧变化可能会导致设备损坏。为设计保护策略，分析了无线充电电动汽车离开时逆变器输出电流和相角的特性。保护策略由欠角保护、过流保护和过角保护组成。设计了检测电路来测量逆变器输出电流和相角的变化。建立无线充电 EV 原型以验证所提出的方法。