A DC-link Series-Parallel Rectifier for 400-V and 800-V WPT Systems with Different Z Classes

 Wireless power transfer (WPT) systems for electric vehicles (EVs) need to accommodate different vehicle models with varying battery voltages and Z classes while ensuring power and efficiency, and considering the volume, cost, and compatibility of the vehicle assembly (VA). To address these challenges, this article proposes a series-parallel dual rectifier architecture based on the LCC-S compensation network. The characteristics of traditional topologies are analyzed mathematically, which may have a low output power under large coupling coefficient variations. Then, the proposed system is presented and the system feasibility is demonstrated through the analysis of power transmission, power losses, and voltage-current sharing between rectifiers. The design principles and process of the system are also explained in detail. The system can adapt to a wide battery voltage range and different Z classes without adding DC/DC converters or changing resonant compensation networks. A 4 kW WPT prototype under Z1 or Z2 class with 400V or 800V battery voltage is established. A maximum DC/DC efficiency of 92.2% is obtained, validating the feasibility of the system.