Design and optimisation of an Ironless Double-rotor Radial Flux Permanent Magnet machine

This paper has to do with the multi-objective optimisation of an Ironless Double-Rotor Radial Flux Permanent Magnet (IDRFPM) machine. The optimisation objectives are to improve efficiency, torque and PM mass. Only the electromagnetic aspects are considered. Due to ease of implementation, a Weighted Sum Method (WSM) is implemented to reduce the multi-objective problem into a single-objective problem. However for this study, the specific weight values are not chosen beforehand, but rather an entire spectrum of weights are used in the optimisation process which, subsequently, generates a large variety of solutions allowing the decision-maker to make a more informed design choice. Furthermore, this paper shows that optimisation function evaluations can be done using either Finite Element Modelling (FEM) or the analytical subdomain analysis method (SAM) and that the results correlate well. The work done to derive a SAM model is also extremely summarised. With SAM, the optimisation process can be speeded up significantly. The solutions of the optimisation process are also briefly discussed.