Study on Leakage Magnetic Field Shielding Method for Electric Vehicle High-Power Wireless Charging System Under Transverse Offset Working Condition

During the working of an electric vehicle wireless charging transfer system (WPT), if the vehicle is transversely offset from the charging area, a greater leakage magnetic field (LMF) will be generated. Shielding LMF can significantly reduce the hazards to the human body. Therefore, this paper proposes a dual active suppression coil (ASC) high degree-of-freedom LMF active shielding method based on an independent inverter drive and proposes a corresponding control strategy by analyzing the ASC current control method, the LMF synthesis mechanism, and the LMF minimization condition. On this basis, the effectiveness of the control strategy was verified by simulation, and the control parameters of the ASC inverter are optimized to ensure the system transmission efficiency while reducing the LMF as much as possible. The experimental results show that the LMF shielding rates of the passive shielding method and the active method were 61.71% and 94.57% at zero coil offset and 44.55% and 66.55% at 100 mm coil offset, respectively.