Electromagnetic design and optimization of dual-stator brushless doubly-fed wind power generator with cage-barrier rotor

This paper explores the feasibility of an intuitive solution torque density for the existing brushless doubly-fed generator by dual-stator and cage-barrier rotor structure, so as to better adapt to the offshore wind power generation. The torque density of electrical machine is related to the key design parameters, such as the machine main dimensions, slot-pole combinations, coupling between stator and rotor, and nonmagnetic ring thickness. According to working principles and design requirements of electrical machine, the dual-stator brushless doubly-fed wind power generator (DSBDFWPG) with cage-barrier rotor is designed, and the key parameters relating to torque density are analyzed and discussed. Meanwhile, the main parameters of electrical machine are optimized by Taguchi method, such as air-gap length and nonmagnetic ring thickness. On this basis, the performance parameters of DSBDFWPG are analyzed by finite element method, which is verified by experimental tests. Through analysis of the results, not only the design requirements are satisfied by the DSBDFWPG, but also the correctness and rationality of machine design method can also be verified. Finally, the torque density and other aspects of designed DSBDFWPG are compared with dual-stator brushless doubly-fed induction generator, doubly-fed induction generator, asynchronous machine, and brushless doubly-fed generator; it demonstrates the torque density improvement of the studied machine with its significance and value.