The High-speed Induction Motor Magnetic-thermal Coupling And Temperature Field Calculation

High-speed induction motor with its high speed,power density,small compacted structure are widely used.It can be directly connected with the load,eliminating the mechanical transmission,improving the transmission accuracy and efficiency,in high-speed operation,the loss is much larger than the ordinary motor,temperature rise caused by high loss Have an important impact on the insulation material performance,motor efficiency and life.Therefore,in the high-speed induction motor design and development stage,the characteristics of the loss and temperature field calculation is of great significance.In this paper,a 2 poles and 24 slot high-speed induction motor as an example,studied the following three aspects:(1)The loss characteristics of the high-speed induction motor were analyzed and calculated comprehensively,including the influence of the skin effect and the adjacent effect on the copper loss.The calculation method of the iron loss separation of the eddy current loss,hysteresis loss and additional loss was introduced.The loss coefficient is used to calculate the iron loss accurately.The empirical formula is used to calculate the loss of the angular contact ball bearing and the analytical method is used to calculate the wind friction loss,the calculated results are compared with the experimental results.The results show that the temperature field obtained by considering all loss of the motor is closer to the real value.(2)The transient electromagnetic field of high-speed induction motor is analyzed by finite element method.The variation of air gap flux density and stator flux density is analyzed.The performance of the motor is simulated by finite element method.Finally,the finite element method is used to analyze the high speed induction motor Under the electromagnetic loss of the separation calculation.(3)The magnetic-thermal finite element method was used to calculate the temperature field of the angular contact ball bearing and the temperature field of the whole machine.The equivalent heat path method was also used to calculate the temperature field of the whole motor,and the temperature of the motor was tested,the experimental results show that the accuracy of the finite element method is higher than that of the equivalent thermal path method.In addition,the rotor is designed to optimize the opening hole,and the temperature field and dynamic simulation calculation is also done,the simulation results show that:rotor opening hole is beneficial to rotor heat dissipation and Optimization of the motor temperature field distribution,and will increase the rotor's first-order natural frequency and critical speed,but will not cause resonance.