A Communication-less Wireless Battery Charger Based on Variable Inductor

Inductive power transfer (IPT) offers clear benefits over wired power transmission in battery charging, including safety, convenience, and automation. In this paper, we introduce an IPT system with a variable inductor on the primary side to achieve constant current (CC) and constant voltage (CV) charging, and zero voltage switching (ZVS) of all switches. The proposed system operates at a fixed frequency, eliminates the need for wireless communication and any secondary-side control, minimizing the complexity and cost of the secondary side especially. The approach is experimentally validated to maintain the charging current and voltage within 3.2% when in those respective modes, with a maximum efficiency of 94.8%.