Mutual inductance is a key parameter in a wireless power transfer (WPT) system that determines transmission power and transmission efficiency. Mutual inductance can be increased, and magnetic leakage can be reduced by adding electromagnetic (EM) shielding materials to the coil structure. However, the calculation of the mutual inductance between two arbitrarily positioned circular coils, including the effect of EM shielding, has not been resolved. In this article, an analytical formula for calculating the mutual inductance between two circular coils with arbitrary relative positions on a double-layer EM shielding is obtained based on the coordinate transformation method and electric field intensity. A series of experiments are carried out to validate the analytic calculations. The experimental results for each of the misalignment cases are compared with analytical predictions and finite-element method (FEM) solutions. The theoretical results and FEM simulation results are in good agreement with the experimental data, which verifies the validity of the proposed method.

中文翻译：

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无线电力传输系统中具有电磁屏蔽的任意位置圆形线圈的互感计算

互感是无线功率传输 (WPT) 系统中决定传输功率和传输效率的关键参数。通过在线圈结构中添加电磁（EM）屏蔽材料，可以增加互感，减少漏磁。然而，两个任意定位的圆形线圈之间的互感计算，包括电磁屏蔽的影响，尚未解决。本文基于坐标变换方法和电场强度，得到了计算双层电磁屏蔽上任意相对位置的两个圆形线圈之间互感的解析公式。进行了一系列实验以验证解析计算。将每种错位情况的实验结果与分析预测和有限元方法 (FEM) 解决方案进行比较。理论结果和有限元模拟结果与实验数据吻合较好，验证了所提方法的有效性。