This letter aims to provide an analysis of selecting the optimal coil position under a dynamic transmitting coil (Tx-coil) to improve the performance of a dual-receiver magnetic resonance wireless power transfer (MR-WPT) system. The expressions of power transfer efficiency (PTE) and optimal load are derived using equivalent circuit model (ECM), and the relationship between coils position and PTE under cross-coupling is discussed; it proves the existence of an optimal transfer distance to achieve the maximum PTE for a symmetric receivers (Rxs) system. The system has a dynamic Tx-coil position variation range under optimal load of maintaining stable and efficient power transfer when the Tx-coil moves within this range. Finally, the theoretical results are verified through experiments in the laboratory. Under the optimal operation, a stable overall efficiency above 75% can be achieved for a system when the Tx-coil moves within this range that the gap of receivers at 100 mm.

中文翻译：

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动态双接收WPT系统保持稳定传输的位置优化


本文旨在分析选择动态发射线圈（Tx-线圈）下的最佳线圈位置，以提高双接收器磁共振无线功率传输（MR-WPT）系统的性能。利用等效电路模型（ECM）推导了功率传输效率（PTE）和最佳负载的表达式，并讨论了交叉耦合下线圈位置与PTE之间的关系；它证明了对称接收器 (Rxs) 系统存在实现最大 PTE 的最佳传输距离。当 Tx 线圈在该范围内移动时，系统在最佳负载下具有动态 Tx 线圈位置变化范围，以保持稳定和高效的功率传输。最后通过实验室实验验证了理论结果。在最佳运行情况下，当发射线圈在接收器间隙为 100 mm 的范围内移动时，系统的整体效率可以稳定地达到 75% 以上。