Hardware design and implementation for Class-E power amplifier for Qi compatible wireless power transfer for consumer electronics

This paper presents the design of a Class E power amplifier tailored for wireless power transfer applications, with an emphasis on achieving system compactness. The amplifier operates at a switching frequency of 100 kHz and delivers an output power of 15 W, conforming to Qi standards. A series-series topology was chosen for the wireless power transfer system. To achieve zero voltage switching (ZVS), the primary side was tuned to a frequency slightly lower than the switching frequency, eliminating the need for an additional inductor. This innovation results in a more compact and cost-effective system without compromising performance. To ensure effective power transfer, the secondary side was tuned to resonate at the switching frequency. Design calculations were validated using LTspice simulations and hardware implementations. This paper also evaluates the efficiency of the designed converter and provides an analysis of power loss. The proposed system is primarily intended for consumer electronics applications, such as cell phone chargers, offering a simplified and efficient solution.