A Series-Parallel Inverter-Based WPT System for Electric Vehicles With Different Input Voltages and Z Classes

Different countries have various grid voltages, and different electric vehicles (EVs) have different chassis heights. Conventional EV wireless power transfer (WPT) solutions require designing different circuits for various input voltages and using different compensation circuits for different transmission distance classes, which hinders the widespread adoption of the WPT technology. To address these two issues, this article proposes an EV WPT system based on series-parallel inverters. The mathematical model of this system is established, and the expression for output power is derived. In addition, current and voltage-sharing characteristics and system losses are analyzed. The design procedure is then summarized to provide a reference for higher power WPT systems. The proposed system offers adaptability to different grid voltages and Z classes without requiring changes to the resonant circuit or the addition of dc–dc converters. And it eliminates the need for a resonant inductor on the ground assembly side, making it a cost-effective solution. Finally, a 3-kW prototype is constructed to demonstrate the feasibility of this proposed system and the maximum overall efficiency achieved is 92%.