Reduction of Eddy-Current Loss in Flux-Switching Permanent-Magnet Machines Using Rotor Magnetic Flux Barriers

Abstract

This paper investigates magnet eddy-current (EC) loss of a five-phase flux-switching permanent-magnet (FSPM) machine. Using magnetic flux barriers in the two proposed rotor topologies, it is possible to reduce some space harmonics in the air-gap flux density, thus reducing magnet EC loss. A 1-D magnetic permeability model is adopted to account for the reduction of the main sub-harmonics as well. Then, the magnet EC loss of both the existing machine and two proposed machines is compared by using time-stepped finite-element analysis. It is shown that the 55.2% and 49.6% EC loss reduction can be achieved by adopting proposed I and proposed II topologies, respectively. The temperature of proposed machine is lower than that of the existing one, and the temperature of both winding and magnet in the new topologies was reduced by 24°. Therefore, the proposed machine model can provide a direct guidance for dependable design and performance optimization of FSPM machines.