Trim method of impedance matching for magnetic resonance coupling system

The working frequency of magnetic resonance coupling wireless power transmission (WPT) system can run to the range from several hundreds of thousands to a few megahertz, therefore, the dynamic impedance matching is the most effective way to keep the system transmission efficiency higher than the setting value. In this paper, we take coupling coefficient and working frequency as the focus of this WPT system and set up one transmission efficiency model, controlling parameter curve is built by solving optimization problems with maximum transmission efficiency and maximum transmission capacity as constraints, all points on this curve meet the transmission efficiency requirements, then available input parameter is extended from one point to the section of space curve. The proposed method makes the system able to dynamically follow the maximum transmission efficiency curve without changing the system topology or adding additional external matching circuits. Experimental results show that the proposed method can significantly improve the magnetic resonance WPT system's adaptability to variation of position and angle between transmit coil and receive coil.