An Efficient Soft-Switching Wireless Battery Charger With Low-Loss Auxiliary Circuit

Aiming at the problems that the soft-switching specialty is easily affected by the perturbation of compensation element parameters and the soft-switching range is restricted for the existing soft-switching wireless battery charger (SS-WBC), a novel SS-WBC with low-loss auxiliary circuit is proposed to solve the above problems. The proposed SS-WBC can achieve efficient charging within the entire charging process based on meeting the constant current (CC) and constant voltage (CV) charging requirements required for the battery. By adding a simple and low energy consumption auxiliary circuit, the switch tubes in the inverter can acquire true zero-voltage switching (ZVS) switch-on and true zero-current switching (ZCS) switch-off, which can effectively eliminate the switching loss in the inverter and soft-switching operation is not influenced by the perturbation of compensation element parameters. Moreover, a novel modulation strategy is used for the inverter. Only one switch in the inverter is in the high-frequency switching state in a cycle, which has a positive impact on improving efficiency. The working principle of the presented SS-WBC is depicted at length, and the soft-switching design rules within the entire charging process are discussed. Finally, a 300 W prototype with 95.1% peak efficiency is built to validate the proposed scenario.