Rotor and stator shape optimization of a synchronous machine to reduce iron losses and acoustic noise

In electric vehicles, a major emphasis is placed on iron loss reduction to maximize machine efficiency and its vibratory and acoustic behavior to meet users´ expectations of a silent drive. This paper describes a method to simultaneously reduce iron losses and magnetic noise of a wound-field synchronous machine considering various stator tooth lengths and rotor pole airgap surface radii. The impact of design parameters on acoustic noise and iron losses is analyzed to provide the possibility to make adequate choices during the design. A novel approach is presented to compute iron losses as well as details of the weak coupling between the magnetic and structural finite element models used to compute the magnetic noise. Simulations results suggest simple rules to improve the machine´s global performance.