High-Efficiency Wireless Integrated On-Board Charger System Using Partial Power Conversion

This paper proposes a wireless integrated on-board charger (WiOBC) for electric vehicles based on partial power conversion (PPC), which can simultaneously charge the high-voltage battery (HVB) and the auxiliary system (AS) with high efficiency. The proposed PPC-WiOBC can operate in two modes: charging mode and driving mode. During charging mode, a dual decoupled four-coil system is utilized to charge the HVB with a constant-current or constant-voltage (CC/CV) charging profile and provide a constant DC voltage for AS. The surplus power will flow through the AS to the HVB via an auxiliary DC/DC converter. In driving mode, the auxiliary DC/DC converter operates backwards and the HVB supplies power to the AS. To meet high-efficiency and bi-directional operation requirements, an auxiliary LC-LLC multi-resonant DC/DC converter, incorporating an additional inductor is introduced. A power ratio δ of the PPC is also introduced to ensure high efficiency. Finally, a comprehensive system parameter design of the PPC-WiOBC is proposed. Experimental results from a scale-down 1kW experimental platform verify the performance of the proposed PPC-WiOBC, with output voltage ranges from 264V to 402V, a peak efficiency of 94.1%, and efficiency > 87.1% throughout the whole charging profile, which is superior to the conventional wireless OBC solutions.