Abstract
Permanent magnet (PM) motors, which have a simple and maintenance-free structure and high performance, have been used widely in the fields of industry applications. The PM motor, however, has some problems on the cost and weight in high power usage.
In this paper, we propose a method for optimizing surface PM synchronous motors (SPMSM) using non linear optimization technique. In the formulation, the performance characteristics are estimated using space harmonic analysis. The accuracy of the formulas is investigated by experiment. The exterior point transformation method and the simplex method are applied to solve the constrained nonlinear programming problem. Eight parameters are chosen as the independent variables, such as number of poles, the stack height, the number of slots per pole per phase, the coil pitch, the ratio of slot width to slot pitch, the width of magnet, the height of magnet and the height of rotor yoke. The SPMSM design is analyzed under four objective functions; the primary weight, the cost of materials, the input KVA and the power rate.
