Analysis of Mutual Inductance Characteristics of Rectangular Coils Based on Double-Sided Electromagnetic Shielding Technology and Study of the Effects of Positional Misalignment

In wireless power transfer systems, the relative positional misalignment between transmitting and receiving coils significantly impacts the system’s mutual inductance characteristics, thereby constraining the system’s output power stability and transmission efficiency optimization potential. Hence, accurate formulas for calculating mutual inductance are crucial for optimizing coil structures and achieving mutual inductance stability. This study focuses on the mutual inductance characteristics of rectangular coils under positional misalignment conditions in a dual-sided electromagnetic shielding environment. Initially, the research deduces the incident magnetic flux density induced by the current in rectangular coils through the dual Fourier transform and magnetic vector potential method. Subsequently, Maxwell’s equations and boundary conditions are employed to analytically examine the induced eddy currents within the shielding layer, allowing for the calculation of reflected magnetic flux density. Based on these analyses, the study derives a formula for mutual inductance using the magnetic flux density method. A prototype was built for experimental verification. The experiment results show that the maximum error between the measured mutual inductance and the calculated result is less than 3.8%, which verifies the feasibility and the accuracy of the proposed calculation method. Simulations and empirical validation demonstrate the superior accuracy and practicality of the proposed formula. This research not only offers an innovative technological pathway for enhancing the stability and efficiency of wireless power transfer systems but also provides a solid theoretical foundation and guiding framework for coil design and optimization.