Improving misalignment tolerance for a third coil IPT charger with load-independent output

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This paper proposes a system to improve misalignment tolerance and achieve constant current (CC) and constant voltage (CV) outputs for an electric bicycle inductive power transfer (IPT) charger. Existing systems typically sacrifice output stability when enhancing misalignment tolerance and often rely on complex control circuits for CC-CV switching. A tertiary coil is utilized to establish a reverse connection with the secondary side coil without affecting the inherent output characteristics. The loosely coupled transformer with a third coil can effectively improve the misalignment tolerance in the x- and y-directions. In addition, a simple and reconfigurable structure is developed, enabling shifts from inductor-capacitor-capacitor-inductor-capacitor-capacitor (LCC-LCC) topology to inductor-capacitor-capacitor-series (LCC-S) topology, and further acquiring load-independent CC and CV outputs. The proposed tri-coil design simultaneously addresses misalignment challenges while eliminating control complexity. JMAG simulation and experimental findings confirm the accuracy of the suggested model and its structural design. The experimental results show that the prototype achieves an output power of 200 W with a maximum efficiency of 92.7%.