Enhancing Misalignment Tolerance Using Naturally Decoupled Identical Dual-Transmitter–Dual-Receiver Coils for Wireless EV Charging System

Abstract

The rapid reduction of power transfer efficiency with misalignment is a matter of grave concern for compact high-power wireless power transfer (WPT) systems. The misalignment tolerance can be increased by using complex control techniques, but the efficient misalignment operation range is still narrow, and efficiency drops significantly beyond that range. This article proposes a novel natural decoupling method to enhance the efficient misalignment operation range for identical symmetrical quadruple-D coils arranged in a dual-transmitter-dual-receiver configuration without requiring any control. Decoupling of multiple transmitters and receivers is essential for efficient zero phase angle (ZPA) operation. At fully aligned condition, the experimental prototype of this design exhibits a peak efficiency of 96% at 2.25-kW output power for a vertical distance of 150 mm. The misalignment operation range extends from +300 to −100 mm for a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$400\times 400$ </tex-math></inline-formula> mm coil size with almost constant efficiency (94.78%–96.19%). The rated power operation points occur at 0 mm (fully aligned) and also at +200 mm (50% misaligned position), thus making it possible to obtain full rated power without fully aligning the electric vehicle (EV).