Material-saving optimization of high-power direct-driven permanent magnet wind generator

High-power direct-driven permanent magnet wind generators (HDPMWGs) are characterized by their low speed, large number of pole-pairs, and considerable usage of permanent magnet (PM) material. Therefore, the cost of the HDPMWGs is higher than that of their counterparts. Based on the analysis of MMF contents of integral-slot windings and fractional-slot windings, the paper proposes a material-saving technique for HDPMWGs. By employing concentrated integral-slot windings, increased number of turns per phase, and rotor pole shift or step skewing, the optimized design reduces the amount of electromagnetic material being used, especially the expensive PM materials, without significantly impacting the performance and manufacture procedure of HDPMWGs. The techniques presented in this paper servers as a useful guideline for material-saving optimization of HDPMWGs.