Electromagnetic-Vibration Characteristics Analysis Of Permanent Magnet Wind Turbine With Air Gap Eccentricity

Due to the manufacturing and installation errors of the permanent magnet wind turbine,it is difficult to avoid the eccentricity of the stator and the rotor,which will cause the uneven distribution of the air gap magnetic density of the wind turbine,resulting in an unbalanced magnetic field,which will aggravate the vibration of the stator and rotor.Under long-term complex service conditions,the eccentric state of the air gap of the wind turbine continues to aggravate,and in severe cases,the rotor is even swept,which makes the wind turbine damaged and invalid.This paper takes a MW permanent magnet wind turbine as the research object,aiming at the complex structure of the large permanent magnet wind turbine,from the perspective of the electromagnetic vibration of the wind turbine caused by the eccentricity of the air gap,using theoretical analysis,simulation calculation and simulation prototype experimental methods,the air The electromagnetic and vibration characteristics of wind turbines under gap eccentricity are analyzed,which provides a certain theoretical basis for the research of wind turbine air gap eccentricity detection methods.The main research contents of this paper are divided into the following three aspects:(1)Considering the influence of air-gap eccentricity on air-gap permeance,carry out the electromagnetic theoretical analysis under the state of permanent magnet wind turbine under air-gap eccentricity,and master the air-gap eccentricity and the air-gap magnetic density and radial electromagnetic force of the wind turbine.,the relationship between the unbalanced magnetic pulling force,and the spatial order and time frequency of the radial electromagnetic force are analyzed.Theoretical analysis shows that when the air gap is eccentric,a sideband component of r±1 is added to the radial electromagnetic force space order,which will affect the vibration of the stator and rotor.For the next step to analyze the wind turbine stator and rotor under the eccentric air gap The vibration response provides a theoretical basis.(2)Using Maxwell to carry out transient electromagnetic simulation analysis of a MW permanent magnet wind turbine,the air gap magnetic density,radial electromagnetic force waveform and unbalanced magnetic tension waveform under the eccentricity of the air gap are simulated and solved,and the Fourier decomposition is carried out.The analysis results show that with the increase of the eccentricity of the air gap,the amplitude of the odd harmonics of the air gap magnetic density increases with the increase of the eccentricity of the air gap;the radial electromagnetic force adds a spatial order sideband component,which is consistent with the theoretical analysis.The results are consistent,the amplitude of the new spatial order increases with the increase of the eccentricity of the air gap;the amplitude of the unbalanced magnetic pulling force has an approximate linear relationship with the eccentricity of the air gap,and the amplitude of the double frequency of the unbalanced magnetic pulling force is It increases significantly with the increase of eccentricity.The simulation analysis of the electrical performance of the wind turbine under the eccentricity of the air gap shows that the amplitude of the no-load back EMF and the harmonic amplitude of the rated load current under the eccentricity of the air gap increase with the increase of the eccentricity of the air gap;as the eccentricity of the air gap increases,The magnitude of the wind turbine core loss,winding copper loss and permanent magnet eddy current loss increases accordingly.(3)The electromagnetic and structural coupling simulation analysis of the generator is carried out jointly by Maxwell and Workbench.The radial electromagnetic force and the unbalanced magnetic pulling force are used as the electromagnetic excitation force,and the vibration response characteristics of the stator and rotor under the eccentricity of the air gap are analyzed.The analysis shows that when the air gap is eccentric,the frequency doubling amplitude of the generator stator vibration response increases,and the second-order radial modal response amplitude is the largest;with the increase of the air gap eccentricity,the rotor rotational frequency and Double frequency amplitude increase.The simulated prototype experiment was carried out to analyze the vibration response of the stator and the rotor under the condition of air gap eccentricity.