Magnetic design considerations to improve nonlinear characteristics of inductively coupled power transfer systems

Abstract

Purpose

This study seeks to apply finite element analysis to study the proximity effect in a multi‐pickup inductively coupled power transfer system, quantify the effect and propose improved pick‐up configurations.

Design/methodology/approach

A mixture of approximate analytical formulae and accurate finite‐element simulations has been used as a tool for qualitative and quantitative analysis. Simplified consideration of magnetic flux paths aids understanding, whereas detailed numerical computation provides reliable performance prediction.

Findings

It is shown that a multi‐pickup formation of conventional E‐pickups may lead to power loss due to negative coupling between neighbouring pickups and that the phenomenon is nonlinear. Thus, two novel configurations for multi‐pickup systems have been proposed, an alternately‐directed Z‐pickup and a spilt‐type E‐pickup, both showing improved linearity, increased total power and more efficient use of ferromagnetic material.

Research limitations/implications

The investigation aimed mainly at the electromagnetic performance, while economic issues will still need to be addressed.

Practical implications

The proposed pick‐up configurations may be very helpful in systems where improved performance is needed but space or configuration limitations restrict or eliminate the possibility of using other designs.

Originality/value

The finite‐element aided magnetic field simulation has proved invaluable in achieving difficult design objectives. The combination of a simplified analytical approach and detailed numerical analysis has provided a reliable tool for accomplishing improved designs.

Citation

Kacprzak, D. and Sykulski, J.K. (2007), "Magnetic design considerations to improve nonlinear characteristics of inductively coupled power transfer systems", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 26 No. 4, pp. 965-973. https://doi.org/10.1108/03321640710756302