Study on a Fully Integrated Coil Based on the LCCL-S Compensation Topology for Wireless Electric Vehicles Charging Systems

This study proposed an integrated methodology for wireless power transfer in electric vehicles employing a dual-coupled LCCL-S compensation system. The proposed loosely coupled transformer (LCT) structure utilizes unipolar coils for the transmitter and receiver, an extended DD coil as a compensation inductor integrated into the transmitter coil. This configuration is designed to enhance charging efficiency under conditions of alignment. In a misaligned state, the system generates dual magnetic flux pathways: one is the transmission between the main coils, and the other is the integrated coil and receiver coil. This dual-pathway approach facilitates increased power transfer efficiency in a misaligned state. Additionally, a finite element simulation tool was utilized to optimize the parameters of the integrated coil. A prototype capable of delivering 3.3 kW power output across a 100 mm transmission distance was developed and compared against other integration techniques. The results indicate that the novel LCT sustains a minimum of 63.6% efficiency at X-axis 150 mm misalignment, outperforming other integration methods by delivering an additional 1.05 kW of power output without necessitating supplementary control methods.