Magnetically Geared Electrical Machines

Considerable research efforts are being carried out worldwide to develop technologies which meet the increasing demand for the efficient utilisation of energy resources. Modern applications, such as renewable energy and electrical vehicles, place a premium on electro-mechanical energy conversion in a power dense and high efficiency manner. Magnetic gears (MG) and magnetically geared machines, offer an attractive alternative to existing systems which may favour the combination of a high speed electrical machine with a mechanical gearbox. This has led to the opportunity to use Pseudo Direct Drives (PDDs) and MGs to be developed for use on an industrial scale. Therefore, in this thesis techniques for facilitating the manufacture and robustness of PDDs are presented, for both radial and axial field topologies. This includes use of alternative windings and soft magnetic composites. PDDs and MGs has so far mainly been developed in the radial topology and little attention has been given to axial topologies. The pole piece (PP) rotor required for MG operation, represents the main difference between PDD/MG and a conventional electrical machine. As such the PP shape and supporting structures have been investigated both in terms of electromagnetic and mechanical performance. Furthermore, detailed electromagnetic and thermal design and analysis of an axial field PDD (AFPDD) with improved robustness was undertaken, and a prototype was manufactured to demonstrate the operation of the AFPDD and validate the predictions.