Design of Four Plate Capacitive Coupler with Enhanced Safe Operating Region for Electric Vehicle Wireless Charging Applications

Capacitive power transfer (CPT) systems have gained popularity due to their distinct advantages over inductive power transfer (IPT) systems, including superior misalignment tolerance, lower cost, and lighter in weight. However, the fundamental issue with the CPT systems is the low coupling capacitance (usually in the picofarad (pF) region) between the transmitter and receiver plates. Owing to the restricted power transfer capability, the CPT systems are unsuitable for high-power, and large air-gap applications. In this paper, a new capacitive-based coupler using a vertical arrangement of four plates is introduced and designed to enhance the power transfer capability under misalignment conditions. In this structure, outer plates are rectangular shaped in order to improve shielding and misalignment tolerance. Inner plates are designed in a hexagonal shape to transfer higher power with minimum electric field emissions. The effectiveness of the proposed CPT coupler is validated through ANSYS-Maxwell simulations. Finally, its performance is compared with other configurations in terms of electric field emissions, misalignment tolerance, and coupling capacitance values.