Design Optimization of Circular Coils in Wireless Electric Vehicle Charging Systems

Wireless power transfer (WPT) technology not only offers ease of use but also safety, reliability, lower maintenance costs, and compatibility for autonomous systems. The idea of using WPT technology to charge electric vehicles (EVs) is gaining popularity. In addition, WPT is a promising candidate for overcoming the range problem of EVs, offering a solution to the limitations of the current battery technology. The WPT is based on the electromagnetic induction principle and consists of a transmitter as well as a single receiver or multiple receivers. The primary objective of WPT is to enhance the power transfer distance and misalignment tolerance while also ensuring high efficiency and high power density. Recent studies have focused on various resonant tank topologies and coil designs to achieve desired objectives. WPT systems widely use circular coils owing to their simple and symmetrical structure and low leakage flux. This study investigated the impact of circular coil design parameters, such as the litz wire, outer diameter, inner diameter, pitch, ferrite cores, and aluminum plate, on the overall system. As a result of examining the effect of the parameters on the system, a circular coil was designed and optimized for the 3.7 kVA WPT system.