This thesis presents research which involves developing, modelling and preliminary building of innovative rotor topologies for aerospace permanent magnet electrical machines. A set of design studies is reported, covering computer aided designs, material properties, finite element analyses at up to 30,000 rpm of the mechanical, thermal, electromagnetic aspects, rotordynamic behaviour, and the manufacturing challenges. The work demonstrates that substantial lightweighting is achievable to improve power density, the final design achieved 62% of the baseline, at an assembled mass of 3.65 kg. The assembled rotor in the baseline machine was 5.86 kg. These gains were achieved by the elimination of the rotor core, through-shaft, alongside lighter weight materials such as CFRP, thermoplastic, and titanium alloy. Traditional CFRP containment sleeves with pre-stress bring several issues, including stress relaxation over its lifecycle, difficulty maintaining pre-stress during manufacture and damage from assembly. Therefore, a core tenet of this thesis targets the elimination of pre-stress in the CFRP sleeve through novel designs. Coefficients of thermal expansion compatibility with CFRP were also considered via finite element analyses, as the effects of dissimilar material properties can be non-trivial. To avoid excessive vibration or instability of the rotor across its operating range, a method for predicting the first critical speed of the rotor, while retaining the full geometrical and material detail, was presented. Electromagnetic forces must be sustained by the structural hub, to this end, a combined electromagnetic and mechanical finite element analysis was performed to verify that the hub in the final design was capable of resisting the mechanical forces produced by the magnets. Design for manufacturability was shown by fabricating the hub with locating features and corresponding features on the magnets. The assembled rotor prototype was planned for mechanical spin test.
