Cogging torque analysis in permanent magnet synchronous generators using finite elements analysis

Abstract

Background A number of generator types are used as energy converters in wind turbines. Despite the advantages of PMSG such as high-power density, high efficiency and low speed, the effect of the cogging torque occurring in PMSG must be reduced. Aim The aim of this study is cogging torque optimization of internal rotor, surface mounted, PMSGs used in wind turbines with high number of slots and poles (84/14). Materials and methods The performance and cogging torque characteristic of the generator have been studied by the finite element analysis (FEA) method. Results While the cogging torque value of the initial generator 580 mNm, with changing skew it is optimized to 277.04 mNm, with changing pole arc offset it is tuned to 550 mNm. With a notch on the magnet and teeth it is minimized to 417.25 mNm and 383.9 mNm, respectively. Finally, increasing the ratio of slot opening to slot pitch, undermine the value of cogging torque. Conclusions The obtained results illustrate that any improvement in cogging torque characteristic using the applied methods accordingly compromises other merits such as flux density, output power, labor and cost.