This paper discusses a super-multipolar permanent magnet reluctance generator (PMRG) for small-scale renewable power generation. The PMRG has 72 stator poles and 96 rotor poles in order to be directly connected to the turbine without a gear box. The designed PMRG has a rated power of over 1.0 kW at 100 rpm. The PMRG has two features to reduce torque ripple; a two-stacked structure where one rotor is shifted by an electrical angle of 180 degrees from the other rotor; and chamfered rotor pole-tips so that the torque waveform consists of only odd harmonics. This structure drastically reduces the torque ripple of the PMRG. The shape of the rotor pole-tips was first optimized by the two-dimensional finite element method (2D-FEM) coupled with a general-purpose optimization program. Next, the load characteristics of the PMRG obtained from 3D-FEM were considered. Finally, the characteristics of the developed 72/96-pole PMRG were measured.
- Chamfered pole-tips
- Permanent magnet reluctance generator (PMRG)
- Small-scale renewable power generation
- Torque ripple reduction
- Two-stacked structure