A Novel Two Degrees of Freedom Control Strategy for Multi-load Magnetically Coupled Resonance System.

The application scenarios of multi-load magnetically coupled resonance (MCR) wireless power transfer (WPT) are becoming more and more extensive, and the independent control of the voltage of multiple loads is imminent. A two-degree-of-freedom control strategy for a dual-frequency dual-receiving coil system is proposed in this paper. Based on low-frequency SPWM, the frequency of the carrier wave is only three times the frequency of the modulating wave. Fundamental voltage and harmonic voltage at switching frequency are obtained on the primary side. A buck converter is cascaded in front of the inverter. By controlling the two degrees of freedom, the duty cycle α of the buck converter and the modulation degree M of the SPWM, the amplitude of the voltage of the two frequencies at the output of the inverter can be independently controlled. The theoretical results are verified by experiments. The experimental results show that the dual-frequency dual-receiving coil system based on dual-degree-of-freedom control can achieve independent control of the output voltage under different loads.