A Novel High-Misalignment Tolerant Magnetic Coupler for IPT System with Concentrated Magnetic Flux and Counteracting Coil

The capability of misalignment tolerance between the primary and secondary coils in an inductive power transfer system is vital. This paper proposes a novel coupling structure composed of a solenoid and a planar square coil with a third coil (SPS-TC) that can significantly improve the misalignment tolerance of couplers. The novelty of SPS-TC is the combination of concentrated magnetic fields and reverse magnetic fields. The proposed SPS-TC has an excellent characteristic that when coils are misaligned in the horizontal direction, the coupling coefficient varies within a very small range. A 1-kW prototype is fabricated. The experimental results show that when the horizontal misaligned distance does not exceed 37.5% of the coil size, the output voltage variation range is extremely small, and the minimum system efficiency is 90.12%. The benefits of SPS-TC are a smaller outer side length and excellent horizontal and rotational misalignment tolerance. It can be used for wireless charging applications in robots, rockets, satellites, unmanned aerial vehicles, etc.