An improved auxiliary circuit for IPT systems to achieve inherent CC‐to‐CV transition and load fault‐tolerant operation

Three-coil inductive power transfer (IPT) charging system can not only achieve inherent constant current (CC) to voltage (CV) transition but also tolerate load open-circuit. However, due the cross-coupling between auxiliary coil and receiver coil, output in CV mode may deviate from significantly, which makes design freedom of three-coil coupler low. By replacing with a transformer, an improved circuit is proposed this paper address issue increase loosely coupled transformer (LCT). The short-circuit open-circuit protection. Besides, optimization LCT easy by impedance matching. operating principle parameters are discussed. A 1 kW experimental prototype built verify feasibility method.