Electromagnetic Design And Theory Regularity Research Of3MW Direct-driven Permanent Magnet Wind Generator

With the increasing intensification of the global energy crisis and people’sawareness of environmental protection, the use of renewable energy is paid moreattention, in which the wind power got rapid development for its related maturetechnology, the scale of its exploitation and the characteristics. The traditional windgenerator is doubly fed induction generator, whose application and development islimited for its complex excitation system and gear box. In this dissertation, a windpower generator is designed using a permanent magnet excitation and direct-drivenmode. The wind power generation system is greatly simplified for direct-drivenpermanent magnet wind turbine generator, and the stability and efficiency of electricpower generator is improved.The direct-driven permanent magnet generator’s new structure, design featuresand operating characteristics are different from the traditional generator. On the basisof these characteristics, the pole-slot cooperation of fractional slot is used in thedesign of direct-drive permanent magnet generator, combined with the use of doublewinding. Well sine of generator’s electricity wave is received and the cogging torqueis reduced effectively. The generator model and circuit model are established in thetwo-dimensional electromagnetic field of the finite element software. Theperformance is analyzed in its load, rated load, the three-phase short-circuitconditions and the rationality of the electromagnetic design is verified. Based on theanalysis results calculate, the power factor, magnetic flux leakage coefficient and thereactance parameter are calculated. Different pole-slot cooperations are analyzedcomparatively in this dissertation. The optimal plan is selected for the minimalinduced EMF harmonic distortion and the minimization of the cogging torque.Demagnetization risk analysis of direct-driven permanent magnet windgenerator is studied importantly. The characteristics of demagnetization and analysismethod of fractional slot permanent magnet generator are explored. Based on the short initial rotor angle parameter, the greatest demagnetization risk time is found.Further more, based on the magnetic density analysis for different surface depth, themaximum demagnetization risk point is determined. The trend of change in magneticflux density curve by the angle between A phase axis and d pole axis from0degreeto90degree is found. Through explores the magnetic flux density variation processof the pole outer surface’s front and back points, the distortion rule of magneticdensity curve and the moving tendency of max demagnetization risk point areobtained.