Enhancing core loss and thermal performance for wireless EV charging with a cross-laminated core structure

Abstract

This paper explores the implementation of laminated cores in inductive power transfer (IPT) systems for wireless EV charging. Two conventional structures are initially evaluated: the horizontally laminated core (H-cores) and the vertically laminated cores (V-cores). Fe-based nanocrystalline materials are applied for these structures due to their excellent core loss properties. The study introduces material modelling and loss analysis methods that combine toroidal measurements with eddy current losses from norm flux. Finite Element Method (FEM) simulations reveal that both structures experience significant flux density and thermal imbalances, creating operational challenges for IPT systems. To address these issues, a cross-laminated structure is proposed, combining the benefits of both horizontal and vertical laminations to reduce thermal imbalances. Simulation results show improved system performance, confirmed by experimental tests. Using the cross-lamination approach, the operational duration of IPT systems can be extended, and the maximum equilibrium temperature at an output current of 10 A is reduced by over 40°C, from 90.4 °C to 47.2 °C. Additionally, efficiency improves by over 0.4 % at 11.1 kW output power. This innovative core design provides a practical solution for implementing laminated cores in high-power wireless EV charging applications, enhancing efficiency and thermal performance.