Efficient system design of capacitive coupling wireless charging for low-power applications

• Published in: Radìoelektronnì ì komp'ûternì sistemi (Online) Vol. 2025; no. 2; pp. 158 - 171
• Main Authors: Ameen, Yasir M. Y., Mohammed, Marwan H., Said, Basil Mohammed
• Format: Journal Article
• Language: English
• Published: National Aerospace University «Kharkiv Aviation Institute 23.05.2025
• Subjects: capacitive coupler design; capacitive power transfer; electric vehicle charging; four-sheet formation; lcl compensation; lclc compensation; wireless power transfer (wpt)
• ISSN: 1814-4225; 2663-2012
• DOI: 10.32620/reks.2025.2.10

The subject matter of this article is the design and analysis of charging pads based on capacitive coupling for wireless power transfer (WPT) in electric vehicle (EV) charging systems. The main goal of this study is to improve the efficiency and overall performance of CPT-based EV charging systems by enhancing the self-capacitance, increasing the coupling efficiency, and minimizing the reliance on oversized or auxiliary passive components while maintaining the compact pad geometry. To achieve this task, two novel four-sheet pad configurations are introduced and evaluated: The M2-four-sheet parallel formation, in which four aluminum sheets are arranged horizontally, and the M2-four-sheet stacked formation, in which the sheets are aligned vertically. Their performance was systematically compared with that of conventional four-sheet layouts to validate the proposed improvements. The proposed formations maintain equal pad dimensions (610 mm × 610 mm) on the primary and secondary sides to ensure effective coupling and high self-capacitance. The methods used include LCLC and LCL compensation topologies resonate with the capacitive coupler and deliver high voltage to the charging pads. Finite-element analysis (FEA) was employed to simulate the coupling capacitance and optimize the coupler’s geometry, while MATLAB software was used to simulate the complete WPT system. The results show that the M2-four-sheet parallel formation achieved significantly higher self-capacitance compared to the traditional layout, with little variation in the coupling capacitance. The M2-four-sheet stacked formation provides even higher self-capacitance than the parallel one and enhances the overall system efficiency without increasing the pad size. Based on these findings, a 1.5-kW CPT system was designed using four aluminum pads with a 150-mm air gap, achieving a DC-DC efficiency greater than 90.5%. Conclusions. The M2-four-sheet parallel formation demonstrates a 175% increase in self-capacitance compared to the traditional layout. Meanwhile, the M2-four-sheet stacked formation improved the coupling coefficient by 21.4%, although it nearly half the self-capacitance relative to the traditional layout. Both designs contribute to significant improvements in system performance and efficiency. Therefore, this study presents a novel symmetric four-sheet pad configuration that significantly improves the self-capacitance and coupling performance, thereby reducing the reliance on external capacitors while maintaining compact geometry and high transfer efficiency.