Investigation of the Interoperability of a Dynamic WPT Pickup with Multiple Source Track Designs

Dynamic Wireless Power Transfer (WPT) technologies enable electric vehicles to be powered from a road whilst in motion. This can overcome the issues of range anxiety and need for large storage capacity of batteries. In order to do this the coils in the road (source) and on the vehicle (pickup) must be designed to be compatible, so called interoperability. A method of assessing this interoperability is presented. This uses investigations of the magnetic field shape and polarity produced by three different types of source coils on the road. It also considers the modifications needed on a vehicle side to ensure interoperability is achieved. In order to produce accurate assessment both finite element analysis and experimental validation are employed to measure the magnetic coupling between the source and pickup for a range of positions. The study shows when coupling factor (k) exceeds 0.1 then interoperability of this combination is possible. This shows that although the twisted stretched track (TST) and lumped double-d (DD) coils have a greater tolerance to offset alignment, the average coupling and percentage of area that exceeds the interoperable requirement is lower than that of the stretched track (ST).