Cost-oriented design of high speed low power interior permanent magnet synchronous machines

In this paper, the characteristic of interior permanent magnet synchronous machine (IPMSM) with concentrated windings is evaluated for three different rotor geometries. The reference machine is a fractional horsepower IPMSM with single-layer magnets (1-layered IPMSM). The maximum output power of the machine is 820 W. Based on the electrical properties and machine cost of the reference machine, IPMSM with two different rotor geometries are designed. The first one is an IPMSM with v-shaped magnets (VPMSM) and the second is an IPMSM with double-layer magnets topology (2-layered IPMSM). The machines are compared in two operating points: one in the base speed area and one in the field weakening range. The focus of the machine comparison are the parasitic effects due to the non-sinusoidal rotor field, e.g. back-emf harmonics, torque harmonics, radial force densities and iron losses.