A wireless power transfer system with automatic frequency tracking in parallel-series model via magnetic resonance coupling

In order to reduce the operating frequency of magnetically-coupled resonant wireless power transfer(WPT) system and to avoid the complex design for frequency tracking system, the parallel-series topology was utilized and an inverter circuit with automatic frequency tracking function was proposed. The theoretical analysis for both the parallel-series topology and the inverter was provided. Two methods were put forward to improve the quality factor of WPT system and curb the fluctuation of operating frequency respectively. A low-power WPT system which operates at 105kHz is designed to validate the circuit topology. The experimental results are presented to verify the analysis and demonstrates the performance of the two methods proposed.