Analysis of a Three-Coil Series-Parallel-Series Topology Based on Asymmetrical Factor Method in Inductive Power Transfer System for misalignment with Constant Current Output

Abstract

In inductive power transfer systems, misalignment will affect the power transmission. In this paper, a three-coil series-parallel-series topology based on the asymmetrical factor method is proposed to minimize primary current with constant current (CC) output and a wide misalignment range. Based on the conventional series-parallel compensation topology, an additional coil with series compensation is introduced. Then, the effect of the coupling variation on the input impedance angle can be reduced by designing the asymmetrical factors, and a constant current output with a wide misalignment and load range can be achieved. A 1680 W prototype has been prepared to verify the topology. The primary current increases by only 12.5% over a coupling coefficient range from 0.15 to 0.35. Zero voltage switching can be achieved over the entire allowed range. This means the proposed topology can minimize the primary current over a wide misalignment range.