An Inductive and Capacitive Combined Wireless Power Transfer System With LC-Compensated Topology

This paper proposes a combined inductive and capacitive wireless power transfer (WPT) system with LC -compensated topology for electric vehicle charging application. The circuit topology is a combination of the LCC-compensated inductive power transfer (IPT) system and the LCLC-compensated capacitive power transfer (CPT) system. The working principle of the combined circuit topology is analyzed in detail, providing the relationship between the circuit parameters and the system power. The design of the inductive and capacitive coupling is implemented by the finite-element analysis. The equivalent circuit model of the coupling plates is derived. A 3.0-kW WPT system is designed and implemented as an example of combined inductive and capacitive coupling. The inductive coupler size is 300 mm × 300 mm and the capacitive coupler is 610 mm × 610 mm. The air-gap distance is 150 mm for both couplers. The output power of the combined system is the sum of the IPT and CPT system. The prototype has achieved 2.84-kW output power with 94.5% efficiency at 1-MHz switching frequency, and performs better under misalignment than the IPT System. This demonstrates that the inductive-capacitive combined WPT system is a potential solution to the electric vehicle charging application.