Calculation and analysis of optimal design for wireless power transfer

In this paper, a detailed theoretical analysis, derivation and calculation of the working characteristics of the electric vehicle wireless power transmission system is provided. Firstly, the circuit model of the resonant wireless power transmission is established using the reflection impedance theory. Secondly, the dual LCCL (Inductance capacitance capacitance Inductance) resonant compensation topology is analyzed, and the equations of the output power P and the transmission efficiency η are obtained. Then, the relationships of the output power P and the transmission efficiency η in respect to the mutual inductance M and the coupling coefficient k, as well as the formulas of the mutual inductance M and the coupling coefficient k is analyzed. And a method to realize the optimal design of the planar spiral coupling coil is proposed using the evaluation function. Finally, a prototype of a 3.3 KW WPT (wireless power transform) system was built. Experimental results show that this way is the best.