Research of Optimization for Transmission Power and Transfer Efficiency of the Loosely Coupled Wireless Charging System

Loosely-Coupled Wireless Charging System (LCWCS), as a new power transmission technology in recent years, has received an extensive concern in the international scope. It can be of great usage for the powering of wireless sensor networks. To get the best charging results, the system optimization is needed. Aimed at the optimization of transmission power and transfer efficiency of the loosely coupled wireless charging system, the main compensation topologies of LCWCS were given, and the relationship between the system mutual inductance, output power and efficiency for mutual inductance optimization were analyzed. Similarly, the relationship between the quality factor, transmission power and efficiency for quality factor optimization were also given. Therefore, the system mutual inductance and quality factor were optimized for achieving the maximum power transfer. Furthermore, for improving the system transfer efficiency with a series tuned primary loop, the system performance has been proposed as a new evaluation index. It takes the system output power, transfer efficiency, cost, size, and reliability into account and with this new index, the system mutual inductance and Q factor were optimized. Finally, simulation and experiment results were given and discussed.