Analysis and Design of Antimisalignment IPT System through Auxiliary Coil Position Reconstruction for Electric Bicycle Applications

In this paper, a wireless charging system architecture is proposed and designed to charge the receiving coil installed on the hollow frame of the electric bicycle (EB) body through the cylindrical charging coils on both sides. Among them, the size of the transmitting coils is designed and optimized to enhance tolerance to three-dimensional misalignment. A novel auxiliary coil position reconstruction (ACPR) method is proposed to actively offset the misalignment effect by adjusting the position of an auxiliary coil nested on the primary coil. The parameters of the resonant network are reconstructed by adjusting the position of the auxiliary coil when the EBs are parked in a misaligned state. The topology enables the voltage reconstruction of an equivalent T/S constant voltage topology, even effectively eliminating the voltage variation caused by the misalignment with simply moving the auxiliary coil. A prototype of the proposed system is built. The misalignment tolerance against output voltage changes in different dimensions is verified through the proposed ACPR method, efficiency of the system is demonstrated to be maintained at around 90%.