Research On Noise And Vibration Characteristics Of The Generator For Large Wind Turbine

Wind power is an important component of renewable energy. The energy project isdeveloped and researched actively in the world. The researches of generator for windturbine also attract attention of many learners in China and abroad. Wind power generatoris the core part of the wind turbine. Permanent magnet generator for large direct-drivenwind turbine is a direction of the development of generator for the wind turbine. Vibrationproblem has always been an important factor to influence the wind turbine operation.Therefore, this paper foci on the study of noise and vibration characteristics of the2.5MWdirect-driven permanent magnet generator for wind turbine.The mechanical, geometrical and physical properties of key parts of the generatorhave been analyzed by some basic formulas of viscoelastic mechanics. The rotor and statorof the generator are modeled, respectively. Then the rotor and stator model are givendifferent mechanical parameters and material parameters. The modes of the generator oflarge wind turbine are analyzed by the finite element software to contrast naturalfrequencies and vibration modes of different models. The key mode influencing thevibration response is found. The reason resulting vibration is analyzed. Furthermore, thesolution avoiding resonance is presented.The electromagnetic analysis of generator for the large wind turbine is done. Theresults of electromagnetic calculation of the generator without load and on load arecompared. The distribution which contains tangential magnetic field density, radialmagnetic field density, tangential force density and radial force density with change ofposition in circumference air gap of the generator are obtained by FEM and Numericalanalysis method.The change tend of magnetic field with the generator rotor rotating are obtained byAPDL to solve the moving magnetic field. The air gap circumference of the generator isdivided into1024sub steps. The variation regularities of air gap magnetic field with time are acquired by calculating circularly. The transient torque and radial electromagnetic forcecan be computed by Maxwell tensile method. Based on the above analysis, the conclusionsare drawn. Main reason caused vibration of low-speed and large-inertia generator is torqueripple of generator rotor. One of the main measures to reduce the vibration of the generatoris to weaken the motor torque ripple. It is one of important condition to design low-noisegenerator that excited frequencies of radial electromagnetic force depart from the naturalfrequencies of the generator stator and rotor avoiding resonance.