Abstract:
Inductively Coupled Power Transfer (ICPT) enables power transfer between two electrically isolated systems over large air gaps using the principles of electromagnetic induction. Such systems are now widely accepted in a range of applications including electric vehicles. Traditionally, ICPT has been applied to vehicular systems where the mechanical misalignment between the primary and secondary are moderately constrained, such as rail based systems. When applied to Roadway Powered Electric Vehicles (RPEVs), where track cables are buried below the roadway surface and a pick-up is located on the base of the vehicle, the mechanical misalignments are substantial, particularly in the horizontal plane. In a RPEV system, the magnetic field generated above the roadway surface by the track cables consists of two components; horizontal and vertical. Most existing applications utilise the vertical component of this field. This thesis proposes a new flat pick-up that predominantly utilises the horizontal component of the electromagnetic field to provide an ICPT solution with improved tolerance to horizontal misalignment. A number of new theoretical concepts and computational techniques have been developed to gain a better understanding of these systems, including a new coupling metric, k, that provides insight into the magnetic coupling of a pick-up independent of the track length, and the Power Transfer Capability (PTC) of a pick-up. Many of the concepts and methods developed can also be applied to other ICPT systems. These techniques provide the basis for a number of assumptions that can be used to simplify the design of flat pick-up systems, resulting in a first order design method. In this thesis, theoretical analaysis, computer simulation and experimental methods are applied to real world devices and applications. During the course of this research, several flat pick-up systems have been fully implemented and tested, including a commercialised people mover system that uses ICPT for battery charging and a prototype, continuously powered, go-kart. The thesis concludes with a preliminary investigation into the use of flat pick-ups in multiphase ICPT systems to provide further improvements to horizontal misalignment. The ultimate result of this is a Quadrature pick-up that exploits both the vertical and horizontal components of the magnetic field above the roadway surface, resulting in previously unrealisable tolerance to horizontal and vertical misalignment. This new pick-up promises to significantly improve the application of ICPT systems to Roadway Vehicles.