Optimization of Coils and Control Strategy for a Three-Phase Magnetically Coupled Resonant Wireless Power Transfer System Oriented by the Optimal Output Power Characteristics

Multi-phase magnetically coupled resonant (MCR) wireless power transfer (WPT) technology, which can effectively reduce the limits of coils spatial locations on power transfer, has become one of the most promising technologies in the mid-range applications. In this paper, a three-phase MCR WPT system was investigated and the equivalent circuit model was built and simplified. Based on the theoretical analysis of the simplified model, the influential factors on output power of the system were revealed, including the phase-shifted angle between each phase, coil turns and spatial locations of receiving coil. Further, coil turns and control strategy of the phase-shifted angle were optimized to ensure the system realize the optimal output power characteristics that was defined as the one with high amplitude and minor fluctuations within the full range of angular misalignment. Finally, the experiments had been carried out to confirm the theoretical analysis.