An Automatic Coil Design Method for Wireless Power Transfer Systems by Current Distribution Analysis

The reduction of coil design cost is essential to integrating wireless power transfer (WPT) systems in electronic devices. However, the power transfer efficiency of WPT systems is influenced by operating conditions, such as the surrounding material and compatibility between transmitter and receiver coils. Further, experienced engineers are faced with the task of adjusting coil parameters using trial and error methods, which is time-consuming. To overcome this problem, we propose a general coil design method based on a current distribution analysis. This design method comprises a two-dimensional current distribution calculation method for the design of a highly efficient coil and coil layout determination method based on the current distribution. We design a coil attached to a metal plate and validate through simulations and experiments that the proposed design achieves the highest power transfer efficiency at 6.78 MHz among multiple coils designed by sweeping design parameters.