Choice of Pole-Slot Number Combination for PM Generator Direct-Driven by Wind Turbine

The permanent magnet (PM) generator direct-driven by wind turbine has the advantages of high efficiency, simple structure and reliable operation, and the features of low speed, multi-pole and large size. How to utilize sufficiently the structural dimension, improve the performance and reduce the cost of the machine by proper choice of the pole number and stator slot number is an important problem to be solved for the design of a direct-driven PM wind generator. In this paper, the performances of a 1.5 MW direct-driven PM wind generator for different pole-slot number combinations with the same machine size are studied based on the circuit-field coupled finite element analysis. The comparative study shows that the choice of pole number and slot number has significant effect on the performance and the better performance can be obtained by proper choice of the pole-slot number combination.