A Misalignment Tolerant Inductive Power Transfer System With AC Resistance Reduction

Misalignment sensitivity is one of the main problems limiting the development of inductive power transfer system. When misalignment occurs, the system output power and efficiency reduce dramatically and cause unstable power supply. Meanwhile, the ac resistance of the inductive power transfer coil increases with the frequency. In medium and high frequency region, it produces large ohmic loss and thermal dissipation, which lead to efficiency-drop and temperature-rise problems. This work proposes a misalignment-tolerant winding pattern to reduce the system horizontal misalignment sensitivity, thermal stress, and coil ac resistance. From the experimental result, the proposed winding pattern reduces the ac resistance maximally by 88% at 2 MHz compared with the conventional winding pattern under the same geometry and wire type. The misalignment tolerance is maximally improved by 46% in terms of the output power with the proposed winding pattern.