NSGA-II Based Optimization of PCB Coil Array for Inductive Power Transfer

Inductive power transfer (IPT) systems are used in a wide range of applications. However, their practicality is reduced by the requirement of good alignment between the transmitter and receiver. One way to improve the misalignment tolerance is to use coil arrays. This paper presents an optimization of PCB coil array for charging of a single coil receiver, both with ferrite. The optimization goal is to maximize the average efficiency while minimizing the coil array size and maintaining at least 15 W of transferred power at any position in the working area. Three array types are evaluated, all of which are based on a three-layer hexagonal pattern to provide homogenous magnetic field. Optimization employs the genetic algorithm NSGA-II with magnetic parameters for the coil array geometry evaluated using Maxwell Ansys. The optimized array operates with average efficiency of 84.4 % across all evaluated alignment positions.