Optimal design of a Hybrid Excited Doubly Salient Permanent Magnet generator for wind turbine application

In this paper, a Hybrid Excited Doubly Salient Permanent Magnet (HEDSPM) generator is investigated and optimized. Generator structure is similar to Doubly Salient Permanent Magnet (DSPM) machine which Permanent Magnets (PMs) are located in stator as main excitation. According to requirement of generator for operating at low speeds, its performance should be suitable for direct coupling to the planned turbine. Due to nature of PM excitation, there is no possibility of controlling the air gap flux density which is a major disadvantage of this type of generators. Accordingly, direct current excitation winding is added to stator assembly. In this paper initially, generator performance and process of voltage inducing along with magnetic field control are discussed. Then, the most appropriate operating point of designing is found by genetic algorithm technique and optimal specification of generator is obtained. The optimized generator is simulated using 2-Dimensional Finite Element Method (2D-FEM) and lastly, results are given to verify the validity of proposed analysis.