Design of a Series-Series Resonant Compensated Inductive Power Transfer System for Wireless Electric Vehicle Charging

Department of Electrical and Electronic Engineering Science, University of Johannesburg, South Africa.

^* Corresponding author: idowua@uj.ac.za

Abstract

This study explores the design of a system for wirelessly charging electric vehicles using inductive power transfer (IPT). It features a series-series (SS) resonant compensation topology. The setup comprises several components: an AC-DC converter, a high-frequency inverter, a resonant tank, coupled coils, a secondary rectifier, and a battery charging unit, all of which are managed by a PI controller. We modelled the entire system in MATLAB Simulink, allowing it to operate efficiently at 85 kHz while delivering 2.5 kW of power across a 10 cm air gap. The SS compensation ensures that both the primary and secondary coils resonate effectively, which helps minimise energy losses and enhances the overall energy transfer. In terms of performance, closed-loop control maintains the output voltage at 400 V within 0.8 seconds, with a voltage ripple of less than 1.5%. Impressively, the system reached a peak efficiency of 93.6% under the rated load. In the results, we highlight that the SS-compensated IPT is a promising solution for mid-range wireless charging. It not only responds quickly to changes but also maintains strong voltage regulation, paving the way for future developments in grid-integrated and bidirectional charging technologies.