The Research Of Characteristics For Fluid Flow And Heat Transfer For Permanent Magnet Synchronous Motor

With the rapid development of contemporary motor industry, permanent magnetsynchronous motor (PMSM) is more widely used in the fields of transportation,chemical, mining and others for its characteristics of small volume and highperformance. However, the increase of power density for PMSM can lead hightemperature rise, which may accelerate aging of insulation and causedemagnetization of permanent magnet material, winding short-circuit. It can lowerthe operating performance of motor and even effect operation reliability and life ofthe motor. Therefore, the rheological properties of the fluid inside the PMSM, theperformance of heat transfer and motor structure are significant to study the impactof its temperature rise characteristics.A50kW PMSM for driven to ships was taken as the example in this dissertationand a3D physical model was established. According to the related knowledge offluid dynamics and numerical heat transfer, using finite volume method (FVM), thefluid field and temperature field were simulated in the rated condition of stableoperation. Through the results of analysis, we knew the maximum temperature riseand average temperature rise of major components inside the motor; thecharacteristics along axial, circumferential and radial direction; the regular of heattransfer between adjacent components, focusing emphatically on the temperaturecharacteristics of the junction box. Through analyzing rheological properties of theair inner the region of fluid to get the numerical distribution regular of every position,which were influenced by the rotation of rotor. Through studying the fluid in thesolving region outside the casing, we knew the cooling air characteristics of thechanging velocity along the axial direction in every duct. Moreover, we analyzed theinfluence characteristics of junction box for air, which flowed along the axialdirection. Combining with simulation results, we concluded the reason for driftphenomenon is the position of the highest temperature rise of major componentsinside the motor. Based on calculated results of original model, four kinds of improvements to thestructure of junction box were put forward in this paper. In the condition of the basichypothesis and boundary conditions same to the original structure, all kinds ofsolutions on the temperature field and fluid field were simulated and compared withevery result. It analyzed the concretely influence characteristics of differentstructures for junction box on external fluid fields and internal temperature fields ofmotor. The results make the theoretical value to the optimization design of junctionbox in PMSM.