Optimization of modular stator construction to improve permanent magnet generator characteristics for very low head hydro power application

Abstract

The using of the transformer core for the permanent magnet generator (PMG) stator teeth provides advantages in low manufacturing costs but on the other hand, causes the cogging torque to be high because of the wider slot opening. To enhance the PMG performance, the optimization of modular stator construction to improve permanent magnet generator characteristics for very low head hydropower application is discussed in this paper. Optimization was performed by comparing eight stator construction's combinations as well as the variation of pole arc to pole pitch ratio. Design and simulation were carried out analytically and numerically using FEMM 4.2. The construction with best characteristics i.e. the highest output and less temperature rise and cogging torque will be considered as the best option. The analysis showed that the best performance was achieved as the compromising of those characteristics and T-ST modular stator construction with pole arc to pole pitch ratio equal to 1 is the construction with the most optimum characteristic.