Research on hybrid magnetic shielding structure for electric vehicle wireless power transfer systems

To address the dual challenges of leakage magnetic field suppression and lightweight design in magnetic shielding structures for electric vehicle wireless power transfer (WPT) systems, a hybrid magnetic shielding structure is proposed in this paper. Initially, based on magnetic shielding theory, the coupling mechanism among the magnetic core material, aluminum spacer, and active-passive shielding coils is thoroughly investigated, and a hybrid magnetic shielding model incorporating multiple shielding methods is established, where the mathematical formulation of this model is systematically derived to quantify its shielding performance. Subsequently, an optimization strategy grounded in the principle of magnetic leakage minimization is proposed to determine the optimal configuration of shielding material volumes while ensuring that the magnetic flux density on the observation surface complies with safety standards. Finally, a WPT system with a power of 4kW is constructed based on the optimized parameters of the magnetic shielding structure. Experimental results demonstrate that the optimized hybrid magnetic shielding structure achieves a 46.49% reduction in core material consumption and a 39.06% decrease in aluminum plate usage while maintaining the magnetic leakage on the observation surface within safety limits. Additionally, the system retains an overall transmission efficiency exceeding 91.23%, alongside a 52.71% reduction in magnetic leakage on the observation surface.