System optimization for wireless power transfer system with double transmitters

Wireless power transfer (WPT) technology makes it possible to get rid of the last power cord for powering the electrical devices. However, the output power and transfer efficiency drop drastically with the increase in transmission distance. To overcome this problem, a WPT system with double transmitters is proposed in this paper. And an equivalent circuit model of the system is built. By calculating, it is found that the number of receiver's turns is concerned with system characteristics. System optimization method by adjusting receiver's turns is derived. To verify the correctness of theoretical analysis, an experimental prototype is presented. It shows that with the system optimization method, the maximum output power is up to 34 W, and a 91% maximum efficiency can be achieved, when the load resistance is 5 Ω.