An Efficient PCB Based Magnetic Coupler Design for Electric Vehicle Wireless Charging

Abstract

This paper proposes an efficient Printed Circuit Board (PCB) design of magnetic couplers for electric vehicle (EV) wireless power transfer (WPT) system. Since a WPT system operates at high frequency, Litz wire typically is used that can overcome high AC resistance, and improve overall efficiency. In EV wireless charging applications, the power level of the system is high, and therefore the magnetic pad size and copper cross-section of the Litz wire used in the magnetic couplers are large which increases the cost and weight. Besides, building the magnetic couplers using Litz wire requires excessive labor work, which causes fabrication errors. Replacing the Litz wire with PCB-based coils raises design and efficiency challenges. A new approach for designing the PCB-based magnetic couplers for high-power EV wireless charging applications is proposed to address the challenges associated with the PCB designs. In the proposed design, the efficiency of the PCB-based design is close to the Litz wire-based design. Moreover, machine assembly replaces the labor work and the magnetic coupler can be implemented with lower fabrication error, weight, and manufacturing cost. In this paper, a 3.3 kW PCB-based WPT system is designed, compared experimentally with the Litz wire setup which achieved a competitive efficiency profile.