Decoupled Three-Phase Winding for Wireless Power Transfer to Electric Vehicles

Heavy-duty dynamic wireless power transfer (DWPT) systems face implementation challenges such as component stress, magnetic interoperability and leakage. Multi-coil systems are a popular solution for stationary WPT, however their application to DWPT is complicated by the need for magnetic balancing. This paper proposes a novel three-phase (3φ) in-road primary that includes an integrated reflection winding. This not only provides a modular solution by magnetic decoupling, but it also contributes to leakage field reduction. The inter-phase coupling is shown to reduce to 1% in the presence of a secondary ferrite plane. Under 10kW operation, the 3φ primary is shown to be capable of reducing leakage magnetic fields by 26% over a conventional rectangular primary. Furthermore, a DC-DC efficiency of at least 94.4% is maintained under secondary misalignment.