| With the increase of electromagnetic load of modern motor,the temperature of each component in the motor also increases accordingly,and excessive temperature rise will directly affect the service life and operation stability of the motor.Therefore,it is of great significance to study the calculation of temperature rise in the motor and the strengthening of cooling structure.The dissertation is mainly composed of the following contents :1.By analyzing the research progress of fluid field and temperature field in ventilation cooling motor at home and abroad,and referring to the relevant principles of electromagnetic field,fluid flow and heat transfer in motor field,the axial and radial hybrid ventilation cooling structure is adopted and its structural parameters are optimized to reduce the temperature rise of the motor and strengthen the cooling performance.2.Taking a YJK450-6,400 k W medium-sized high voltage induction motor as the research object,the electromagnetic field calculation model and fluid-solid coupling model of the motor were established.The loss values of each component of the motor were calculated by Maxwell platform based on electromagnetic field theory,and the numerical calculation of the temperature field was substituted as a heat source.On the premise of grid independence verification,the numerical simulation results and prototype test results are compared and analyzed.The research results shows that along the axial direction,the temperature rise distribution of the prototype increases first and then decreases,and the maximum value is 84.1 K at the stator winding.The winding temperature rise error between the numerical calculation and the test results is 4.44 %,which verifies the rationality of the model and the solver within the allowable error range.3.Because the temperature distribution of the axial ventilation cooling structure of the prototype was not uniform,and the local temperature was too high,on this basis,the axial and radial mixed ventilation cooling structure was adopted.The influence of temperature rise on the steady state of the motor was studied by magnetic-fluid-solid coupling simulation.The temperature rise uniformity coefficient was proposed to quantitatively evaluate the cooling effect of the two ventilation structures.The results show that the temperature rise distribution of the hybrid ventilation structure is more uniform,and the temperature rise uniformity coefficient of the inner and outer winding of the motor is increased by 85.78 % and 6.23 % respectively compared with the axial ventilation structure.4.The influence of the height and number of radial air ducts and the change of ventilation groove steel structure on the temperature rise of motor was further discussed.Taking the temperature rise of motor stator winding as the evaluation standard,the orthogonal analysis table of three factors and three levels was established,and the order of the influence of three structural parameters on the temperature rise of winding was determined as follows : the height of radial air duct > the structure of ventilation groove steel > the number of radial air ducts.Based on the calculation results of orthogonal analysis table,the influence of structural parameters on the temperature rise of the motor is further studied.Finally,in order to obtain the optimal combination of cooling structures,the multi-factor comprehensive comparative analysis was carried out on the height and number of all radial ducts and the structure scheme of ventilation channel steel.The research results show that when the height of radial ducts is 6 mm,the number is 13,and the structure of ventilation channel steel is a single-row scaled structure,The average temperature rise of the motor winding with axial-radial hybrid ventilation structure is the lowest,which is 6.6 K lower than that of the prototype,and the cooling performance is increased by 8.8 %,in which the temperature rise uniformity coefficient of the inner and outer windings is increased by 88.13% and 19.75% respectively. |
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