Stability Analysis of Wireless Power Transfer System with Rotatable Solenoid Coils

This paper primarily focuses on the analysis of the coupling coefficient and efficiency of a wireless power transfer (WPT) system employing solenoid coils, especially during the rotation of the coils. In this study, a coil modeling method with a coordinate system is adopted to derive the changes in the coupling coefficient based on the angle between the normal vectors of the two coils during rotation. Since the planes of the Solenoid coils are not on the same horizontal plane, the least squares method is used to fit the normal vectors of these planes. Subsequently, the variation curve of the coupling coefficient over one rotation period is derived and compared with the coils of the prototype. Finally, a prototype with an LCC-S resonant compensation method is developed, and the experimental results show that the output voltage of the prototype remains stable even when the coils are rotating, and the overall efficiency reaches 92.06%.