Research On Internal Flow Heat Characteristics And Performance Optimization Of Motors With Multiple Ventilation Structures

With the rapid development of science and technology,the level of social economy continues to improve,and the demand for electric energy in various fields is also growing.For the sustainable development of energy,wind energy has been vigorously developed as a green energy.Wind turbine is necessary for wind power conversion.In recent years,permanent magnet wind turbine has advantages such as stronger grid compatibility,lower maintenance costs,and lower energy consumption,which make it play an important role in the wind power industry.However,with the increasing power of the generator,the temperature rise will also increase significantly,which seriously threatens the performance and safety of the generator.Therefore,it is necessary to study the cooling method,cooling structure and cooling effect of the generator comprehensively.And the key factors affecting the efficiency of the generator is found out by using the corresponding means to study the temperature rise and its distribution characteristics.Then the temperature rise will be reduced by improving the structure of the generator reasonably.This thesis takes a 3MW permanent magnet wind turbine as an example,based on the theory of electrical machinery and numerical heat transfer,and combined with the mechanism of fluid-heat coupling,two solving domain models are established according to different boundary condition setting principle and the actual structure of the generator.Then the fluid flow characteristics and heat transfer performance of the generator are analyzed.In terms of fluid field,the trace lines distribution,radial section,radial ventilation ditch and gap velocity of the stator and rotor are analyzed in detail.In terms of temperature field,the temperature rise of stator winding,stator core and permanent magnet is studied.The difference between calculation results from different field settings is obtained through comparative analysis,which lays the foundation for subsequent calculation and analysis.According to the analysis results,the structural optimization scheme is proposed.Due to the eddy current generated by the fluid flow at the end of the winding and the windshield of the generator,the heat dissipation performance is poor.In order to weaken this phenomenon,it is proposed to add ventilation channel steel and optimize the structure of windshield.Finally,the numerical method is taken to prove superiority of these schemes.The results provide a certain theoretical basis for the calculation of fluid field and temperature field of large wind turbines.