Multi Physical Field Analysis And Cooling Fan Optimization Of Compact And High Efficiency Three-phase Asynchronous Motor

This project is an important part of the key research and development project of Shanxi Province "research and development of YX2 series 10 k V compact high efficiency three-phase asynchronous motor"(project number: 201803d121008),which mainly aims at the problem of high internal temperature during the operation of compact motor.Compact high-voltage asynchronous motor is derived from the development of medium-sized high-voltage asynchronous motor.The purpose of research and design is to compress the volume capacity of the motor and improve the power density.Compared with ordinary high voltage induction motor,the center height of compact motor is reduced by two grades at the same capacity.At present,the compact series cage type variable frequency adjustable speed three-phase asynchronous motor developed by Siemens belongs to compact asynchronous motor,which is also a common compact motor in the market.Due to the small internal space,high power density and serious heating of stator and rotor in this series of motors,in order to meet the reliable operation of high-voltage asynchronous motor for a long time under high power density,it is necessary to ensure that the maximum temperature in the motor and the maximum temperature in the winding meet the requirements of the current selection of insulation grade under the normal operation of the cooling system.Therefore,it is necessary to study the heating and cooling of the motor to ensure the safe operation of the motor and extend the service life of the motor.In this paper,y2-500-6 compact high voltage induction motor is taken as the research object.The electromagnetic finite element model and three-dimensional solid model of the motor are established.The transient electromagnetic field,fluid field and temperature field of the motor are numerically simulated by using the finite element method,and the loss values,the distribution of fluid field inside and outside the motor and the maximum temperature inside the motor are obtained.In order to further improve the cooling capacity of the motor,this paper discusses the influence of the change of the geometric design parameters of the cooling fan on the cooling performance of the fan,and optimizes the structure of the fan on this basis.The specific research contents are as followsThe two-dimensional electromagnetic model of the prototype is established,and the wave forms of current,induced electromotive force,torque and speed,as well as the distribution of magnetic line of force and flux density are calculated respectively under no-load condition and rated load condition;The loss value of the stator and rotor under the rated load of the prototype is determined,and the loss value is converted into the heat source density,which provides the basis for the subsequent calculation of the temperature field;The effects of air gap length,winding turns and stator slot width on the efficiency,power factor,iron loss,copper loss,torque and output power of the motor are discussed.The three-dimensional solid model of the prototype is established,and the external body field model and the internal air fluid field model of the prototype are established.The finite element mesh of the external fluid field model is generated,and the fluid motion model,control equation and corresponding boundary conditions are selected to calculate the external fluid field of the motor,and the fluid motion of the external fluid field is analyzed;The internal fluid field model is meshed by finite element method.After setting the corresponding boundary conditions,the internal fluid field is calculated,and the fluid distribution and motion of the internal fluid field are analyzed;The temperature field of each part of the motor under the action of double fan and no inner fan is calculated respectively,and the temperature distribution law of the stator and rotor is obtained,and the distribution law is analyzed.The three-dimensional solid model of external cooling fan is established to calculate the air volume,efficiency and pressure difference performance curve of the prototype at rated speed;The effects of the number of fan blades,the outer diameter of the blades,the inclination angle of the fan rear disc,the blade cutting angle and the distance between the fan and the inlet of the hood on the air volume and efficiency of the fan are calculated respectively;The orthogonal test of three levels and three factors was established,and the structural parameters with better performance were selected as the optimization scheme through the orthogonal test.The wind speed and the maximum temperature of the shell surface were compared under different schemes,The results show that the optimized fan can reduce the motor temperature.