Research on Active‐Shielded Single‐Sided Magnetic Core Structure for Wireless Power Transfer Systems in Electric Vehicles

ABSTRACT In electric vehicle wireless power transfer (WPT) system development, the conflicting relationship between vertical leakage magnetic field suppression and magnetic shielding material quantity constitutes a key technical challenge. Traditional schemes are addressed by this study, where excessive shielding material usage is found to fail leakage field strength requirements (< 27 μT) under offset conditions. Consequently, an active‐shielded single‐sided magnetic core structure is proposed. First, a rectangular coil magnetic field calculation method based on vector magnetic positions is adopted for preliminary analysis of the target‐surface leakage field, establishing theoretical foundations for magnetic leakage optimization. Second, the proposed structure's shielding principles are detailed through analysis of copper and aluminum shielding losses, with its mathematical model derived. Subsequently, based on target‐surface leakage field distribution, an optimization method minimizing shielding material volume and quantity is proposed while ensuring magnetic field safety. Finally, a WPT system implementing the optimized active‐shielded single‐sided magnetic core structure is developed, with effectiveness demonstrated through simulation and experimental verification. Results confirm that magnetic core implementation is required only at the receiving end without additional magnetic shielding metals, achieving leakage flux below 27 μT at the 10‐cm vertical observation surface with transmission efficiency exceeding 88% under both aligned and offset conditions.