Calculation of mutual inductance from magnetic vector potential for wireless power transfer applications

Recent renewed interest in commercial development of wireless power transfer through magnetically-coupled resonant circuits has shown the need for a computational tool that can calculate the mutual inductance of coils of arbitrary geometry and spatial orientation. This task is often performed by finite-element analysis (FEA), but this requires both access to such software and a degree of expertise on the part of the designer. This paper introduces a simple-to-use Matlab-based computational tool for calculating mutual inductance for inductors in free space based upon magnetic vector potential.

I. Introduction

Recent years have seen a renewal of interest in wireless power transfer (WPT) systems, with applications announced or proposed as varied as contactless charging of batteries in consumer electronics^[1], powering of desktop peripherals^[2], charging of electric-vehicle batteries [3], and powering of endoscopic robots^[4]. Application of such systems in practice, however, involves coils of various geometries and variable orientations. Such variable geometries are often investigated through finite-element analysis (FEA), e.g.,^[5]. However, a simple tool for computing mutual inductances between such coils that did not require expertise in FEA or access to FEA software could have significant benefit to the designer of WPT systems.