Enhancing coupling coefficient and efficiency in wireless power transfer: A comparison of ferrite block and magnetic composite particle material^☆

Abstract

Magnetic components play a critical role in Wireless Power Transfer (WPT) systems by enhancing the coupling coefficient, thereby improving efficiency and power transfer capacity. In high-power WPT systems for electric vehicles and battery-electric locomotives, Ferrite Blocks/Bars (FBs) and Magnetic Composite Particle Materials (MCPMs) are commonly used to fabricate magnetic components, both demonstrating notable performance. However, limited comparative studies have examined their effects on WPT systems. This paper presents a comparative analysis of FB and MCPM in WPT systems, focusing on the coupling coefficient and system efficiency. First, the magnetic reluctance circuit of the WPT coupler is analyzed. Based on this analysis, MCPM couplers without grooves, MCPM couplers with Grooves (MCPM/G), and FB couplers are designed and optimized using finite element analysis to maximize the coupling coefficient under constrained conditions. The optimized couplers are then fabricated and integrated into a prototype WPT system, and their performance is validated through testing. Compared to the coil-only coupler without magnetic components, the simulated and experimental coupling coefficients show that the MCPM coupler improves by 35.36 % and 25.25 %, the MCPM/G coupler improves by 44.96 % and 27.00 %, and the FB coupler improves by 58.82 % and 41.81 %. Regarding maximum efficiency, the MCPM, MCPM/G, and FB couplers achieve increases of 1.22 %, 1.55 %, and 2.39 %, respectively. These results demonstrate the effectiveness of magnetic components and the differences among various materials in enhancing the performance of WPT systems.

Keywords

Wireless power transfer / Coupling coefficient / Magnetic composite particle material / Magnetic concrete / Finite element analysis

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