Investigation of wireless power transmission compensation methods in semi-dynamic mode and selection of suitable air distance with usability in subsurface systems

This study investigates the compensation methods used in the wireless power transfer system in the semi-dynamic subsurface mode. Choosing the appropriate air gap for wireless power transfer requires technical considerations. Along with these, the characteristics of each coil and the compensation network structure should also be considered. In this study, the structure of common compensation networks for the power transfer system in the semi-dynamic subsurface mode was investigated and after examining the different characteristics of each compensation network, further investigation and testing was performed for the selected networks. The air gap of power transfer in the system has an inverse relationship with the coupling coefficient of the system, so that with increasing the air gap excessively, the coupling coefficient decreases significantly and the power transfer is completely cut off, so the ideal coupling coefficient range in the system with circular coils was expressed for changing the air gap. The appropriate compensation network structure for wireless power transmission in semi-dynamic mode with 3 kW power and appropriate airspace for receiving the maximum efficiency power was selected. Suitable efficiency of the converter was obtained with the selected compensator network and an approximate air distance of 40% of the diameter of the pad. The results of the research have been investigated and confirmed using PSIM software.