Compact contactless power transfer system for electric vehicles

TLDR

Electric vehicles require a compact, lightweight, high‑efficiency contactless power transfer system with a large air gap and misalignment tolerance, and double‑sided winding transformers are expected to meet these needs better than single‑sided ones. This work develops a novel transformer employing series and parallel capacitors, rectangular cores, and double‑sided windings, and proposes split cores to lower ferrite core costs. The transformer design incorporates series‑parallel capacitor networks, rectangular cores, double‑sided windings, and split cores to achieve compactness and cost reduction. The prototype delivers 1.5 kW output power with 95 % efficiency in the normal position.

Abstract

Electric vehicles (EVs) have been attracting considerable interest recently. A contactless power transfer system is required for EVs. Transformers can have single-sided or double-sided windings. Transformers with double-sided windings are expected to be more compact and lightweight than transformers with single-sided windings. A contactless power transfer system for EVs needs to have a high efficiency, a large air gap, good tolerance to misalignment and be compact and lightweight. In this paper, a novel transformer using series and parallel capacitors with rectangular cores and double-sided windings that satisfies these criteria has been developed, and its characteristics are described. It has an output power of 1.5 kW and an efficiency of 95% in the normal position. To reduce the cost of expensive ferrite cores, a transformer with split cores is also proposed.