Browsing by Author "Joss, Andreas"

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    Design and Optimisation of a Hub Drive Electrical Motor for an L2 Class Electrical Vehicle for Sustainable Urban Transport Applications
    (Stellenbosch : Stellenbosch University, 2018-12) Joss, Andreas; Strauss, J. M.; Randewijk, P. J.; Stellenbosch University. Faculty of Engineering. Dept. Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: This thesis is a comparative study of the electromagnetic aspects, between the Ironless Double-rotor Radial Flux Permanent Magnet (IDRFPM) machine and the Single Outrunner Rotor Synchronous Permanent Magnet (SORSPM) machine for the application of the Mellowcabs L2 class direct-drive electrical vehicle. The IDRFPM machine is analysed analytically using the subdomain analysis method, and validated using a Finite Element Method (FEM) package. Two conductor types are considered for the SORSPM machine, namely Litz wire and solid copper bars. The SORSPM machine is subsequently analysed using a FEM package. The IDRFPM and SORSPM machines are both optimised for various pole numbers with priority given to efficiency, torque density and torque ripple. The optimisation results conclude that the IDRFPM machine has superior performance with regards to efficiency, power factor and torque ripple. However, the torque density of the IDRFPM machine (2.70 N_m/kg) is much lower than that of the SORSPM machine (7.17 N_m/kg). The IDRFPM machine’s low torque density makes it an infeasible choice, as it would increase the vehicle mass significantly, requiring yet a larger IDRFPM machine to provide sufficient hill-climbing capability. A first attempt into a possible method of constructing the SORSPM machine using solid copper bars reveals that the complexity would be too high. The construction complexity, together with unconvincing performance gains of the solid copper bar type, makes the SORSPM machine using Litz wire the preferred candidate for the Mellowcabs vehicle.