Modeling and investigation of 4-coil wireless power transfer system with varying spatial scales

As a mid-range wireless power transfer (WPT) technology, magnetically coupled resonant (MCR) WPT has become a reseach focus in recent years. In this paper, an equivalent circuit model of 4-coil MCR WPT system was presented, along with the formulas of the output power and transmission efficiency. Besides, to comfirm whether spatial misalignments will influence the transmission characteristics of the system, the relationship between the mutual inductance and the spatial misalignments of the coils was analyzed, and the transmission characteristics under various spatial scales was revealed. An experiment circuit was designed and experimental results were well consistent with the theoretical analysis.