Stabilization Control of Output Power in Double-Source Wireless Power Transfer Systems Without Direct Output Feedback

Output power of a wireless power transfer (WPT) system based on magnetic resonant coupling is required to be stable for powering mobile devices. Thus accurate measurement of transmitting distance or mutual inductance, which has a significant impact on output power, is of great necessity. In this letter, a wireless power transfer system with double sources is proposed to broaden the stable region of output power. In addition, detection of mutual inductances between coils placed in arbitrary positions is presented based on measurements of input voltages and currents without any direct output feedback. By using detected mutual inductances, this letter puts forward a coordinated control strategy of double sources to meet the load power demand. Experiments are finally conducted to verify the feasibility and correctness of the mutual inductance detection method as well as the stable power control strategy.