Super-Multipolar Permanent Magnet Reluctance Generator Designed for Small-Scale Wind-Turbine Generation

A permanent magnet reluctance generator (PMRG) has almost the same structure as a switched reluctance generator, but has permanent magnets in the stator yoke. Therefore, neither an exciting circuit nor a position sensor is required. This paper describes a super-multipolar PMRG for small-scale wind-turbine generation, which can be directly connected to the turbine without a gear box. The designed PMRG has two features for reducing torque ripple drastically; the first one is two-stacked structure that one rotor is shifted by 180^° in electrical angle from the other rotor; the second one is that the rotor pole-tips are cut off. To find the optimum shape of the rotor pole-tip efficiently, the coupled analysis of finite element method and a general purpose optimization program is employed. In addition, load characteristics of the PMRG are indicated.