Research On Temperature Rise And Loss Of Axial Reluctance Type Compound Rotor High Speed Motor

Among the many advantages of high-speed motors,the most prominent advantage is its high power density and small size.Compared with traditional motors,high-speed motors have high speed and high efficiency,and can be directly connected to the load without additional mechanical transmission devices.So that the cost of work,operation and maintenance is greatly reduced.Therefore,the demand for high-speed motors in various fields has increased significantly,especially those involving high-precision and high automation requirements.In actual operation,the loss and temperature rise of high-speed motors need to consider the mutual influence and restriction of various physical fields,including electromagnetic field analysis,temperature field analysis,fluid mechanics analysis,stress analysis,etc.,to study the relationship between various physical fields The coupling effect is of great significance in analyzing the loss and temperature rise of high-speed motors in the development stage and later performance improvement of high-speed motors.In this thesis,the axial reluctance type high speed motor with compound rotor is studied.The motor has a rated power of 3k W and a rated speed of 20000 rpm.The research in this thesis is mainly divided into three aspects,namely the study of high-speed motor wind friction loss,the analysis and calculation of other losses,and the temperature rise distribution of high-speed motor.Firstly,the conformation of the high-speed motor studied in this thesis is introduced,and the air gap model to calculate the wind friction loss is established.Because of the high speed of the high-speed motor,the air friction is produced in the motor and the external of the rotor of the motor.The braking torque is produced by the rotor of the motor,then there is the wind friction loss.The wind friction loss of medium and low speed motors is small,which can be calculated by empirical formula;while the wind friction loss in high-speed motors accounts for a large proportion,the wind friction loss of high-speed motors needs to be calculated more accurately through fluid mechanics analysis.By comparing the influence of friction coefficient and speed on wind friction loss,the law is found to provide basic data for reducing wind friction loss.Secondly,this thesis analyzes and calculates other losses of high-speed motors.Divide the motor area,analyze the magnetic flux density waveforms of the characteristic points or circles in each area to know the layout of the core loss,and then calculate the core loss by means of the finite element simulation software;the copper loss of the winding is calculated in line with the analytical formula,and make a comparison and confirm with the finite element simulation results.Then the bearing friction loss and stray loss are calculated,and the efficiency of the motor is calculated.Finally,established a model to calculate the temperature rise distribution of the motor,and a cooling system is added to the motor.The main loss of the motor is converted into heat density and impose on the boundary qualifications of the temperature rise model,and the temperature rise calculation is performed through the heat flow coupling module.The water speed and the wind speed are changed,and the cooling consequent of the cooling system is given by the simulation results of temperature rise diagram.Through the comparison of the two cooling effects,it is proved that the air cooling system is more effective in cooling the high-speed motor.