A Design Approach for Direct-Drive Permanent-Magnet Motors

This paper presents a design approach of a direct-drive permanent-magnet (PM) motor for a medium-sized injection-molding application. In the proposed approach, genetic-algorithm (GA) loop works to optimize the lamination design in order to meet the requirements for the target application. To achieve the design optimization within a realistic time scale, the repeated calculation required to obtain fitness evaluation does not use finite-element analysis (FEA) but consists of a geometric flux-tube-based nonlinear magnetic analysis developed specifically for this class of motors. The validity of the proposed design approach is verified through several comparative studies on the design results with FEA using a 942- 88.8-kW three-phase multipole interior PM motor, which is designed by the proposed optimizing GA approach.