Optimal Design of an Exterior-Rotor Permanent Magnet Generator for Wind ‎Power Applications ‎

Document Type : Research paper


Department of Electrical and Computer Engineering, Babol Noshiravani University of Technology, Babol, Iran


High power permanent magnet synchronous generators (PMSGs) are suitable for wind power applications because of their high efficiency. According to the electromagnetic machine design principles, the main disadvantages of low-speed and high-power generators are large size, heavy weight and high manufacturing cost. The main objective of this paper is to optimize the exterior-rotor PMSG for direct-drive wind turbine applications in order to reduce the generator system cost under design constraints. At first, a multidisciplinary and accurate model is proposed for optimal designing of exterior-rotor permanent magnet wind generator system. Next, the design variables that affect the generator system cost are investigated and specified. Furthermore, the impact of these variables on generator efficiency as one of the main design constraints, are investigated. At last, the unified particle swarm optimization (UPSO) technique is used to optimize the design variables based on the presented analytical model. By comparison the optimal design results of this study with two 500-kW inner-rotor PMSGs and one 15-kW prototype exterior-rotor PM wind generator, it is shown that the proposed method yields an optimal design with lower total volume, lower generator system cost and higher efficiency. Moreover, 3-D finite element analysis is employed to verify the obtained results of the proposed optimal design of 500-kW exterior-rotor PMSG.


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