Computational modelling for type-II superconductivity and the investigation of high temperature superconducting electrical machines

In recent years, the possibility of incorporating type-ll superconducting materials into engineering power applications such as motors, generators, bearings and levitation systems has attracted much attention. However, in order to fully develop the potential of using these relatively new materials in such applications, suitable computational modelling is required. The aim of the research presented in this thesis was to further the development of electrical machines incorporating high temperature superconductors (HTSs) by formulating and then implementing mathematical models. After identifying and justifying necessary assumptions, two such models are developed: the first deriving from the ideas of fluxon motion leading to a finite difference scheme, and the second deriving from more fundamental macroscopic ideas of induced currents leading to a finite element formulation. In both cases, the critical state model of type-ll superconductivity is employed and, because of its intrinsic non-linear properties, computational numerical solution techniques are utilised. After validating the modelling techniques with simple problems, and comparing to approximate analytical solutions when available, the remainder of the thesis concerns the modelling of HTS electrical machines and in particular, hysteresis, reluctance, trapped-field and linear motors. In each case, by evaluating the magnetic field and current distributions inside the machine, the roles of the superconducting materials are clearly revealed. Once this has been achieved, further studies indicate the most desirable parameters which are expected to optimise the performance. (author)Available from British Library Document Supply Centre-DSC:D213677 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo