Power Factor Correction Focusing on Magnetic Coupling of Parallel-connected Wires for Inductive Power Transfer System

This paper proposes a power factor correction method of a non-resonant IPT system using a four-winding transformer. The proposed technique is applied to the IPT system with a dual active bridge converter to reduce conduction loss and winding loss. When two pairs of the primary-side and the secondary-side wires are connected in parallel, the low coupling coefficient between the wires driven by in-phase voltage corrects the power factor from the viewpoint of the power supply due to the improvement of an equivalent magnetic coupling. The effect of the power factor correction is assessed by experiments with two four-winding transformers, coupling coefficient of which is different from each other. As experimental results, it is confirmed that a maximum efficiency with the lower coupling coefficient between the parallel connected wires is improved by 3.0% in comparison with the system, which has the high coupling coefficient.