Evaluation of Ferriteless Magnetic Topologies for Dynamic Inductive Power Transfer to Electric Vehicles

This paper presents a comparative evaluation of DWPT magnetic topologies aided by design optimisation. With multiple topologies for DWPT magnetics being proposed, it is necessary to identify the best low-cost and compliant designs suitable for public infrastructure. This comparison targets a ferrite-less primary with a power density of 50kW/m. The design objectives are to minimise copper and electronics cost, maximise output power and achieve leakage compliance. For each topology, an NSGA-II optimisation is conducted to select the best design. The magnetic parameters are rapidly resolved with analytical equations for ferrite-less coils, and match closely with ANSYS simulation. Furthermore, the power output is verified by PLECS simulation. The single phase poles across and along the road, and two phase meander track are found to have the best aggregate performance under the selected design criteria. The circular primary is a good low-cost solution, however has a lower average output power than the aforementioned designs. The three-phase with field across the road primary is a promising solution due to low electronics cost, however leakage fields can be an issue. The three-phase with field along the road primary struggled with the high air gap and lack of ferrite leading to low couplings.