The leakage electromagnetic field (EMF) from the wireless power transfer system caused by loose coupling is hazardous to the human body and sensitive electronic devices. Studies have shown that the reactive LC coil has good shielding effect in the internal area nearby the coil central axis but poor shielding effect in the external area around the coil boundary. To overcome this, a hybrid shielding structure is proposed, which weakens leakage EMF in the external area by surrounding reactive LC coil with a ring-shaped aluminum plate. Two representative target planes are selected for evaluating the shielding effect. To minimize the average of magnetic flux density on target planes, the position and equivalent inductance of the proposed structure are optimized through ANSYS Maxwell. Experimental results show that, compared with the shielding method using horizontal aluminum plate, the proposed structure has an improvement of 68% shielding effect for target plane at coil alignment, even 88% for individual points, but with a 1.02% drop in efficiency. It also performs well under coil misalignment condition, and the shielding effect is still improved by 50% when the coils are offset by 100 mm.

中文翻译：

---

用于无线电力传输系统的改进型 LC 线圈混合屏蔽


松散耦合引起的无线电力传输系统的泄漏电磁场 (EMF) 对人体和敏感电子设备有害。研究表明，电抗式LC线圈在线圈中心轴附近的内部区域屏蔽效果良好，但在线圈边界周围的外部区域屏蔽效果较差。为了克服这个问题，提出了一种混合屏蔽结构，通过用环形铝板包围电抗 LC 线圈来减弱外部区域的泄漏电动势。选择两个有代表性的目标平面来评估屏蔽效果。为了最大限度地减少目标平面上的磁通密度平均值，通过 ANSYS Maxwell 对所提出结构的位置和等效电感进行了优化。实验结果表明，与水平铝板屏蔽方法相比，该结构对线圈对准处目标面的屏蔽效果提高了68%，对单个点的屏蔽效果提高了88%，但效率下降了1.02%。在线圈错位的情况下也表现良好，当线圈错位100mm时，屏蔽效果仍提高50%。