Analysis and Calculation of Magneto-Thermal-Structure Coupling of Double-Skewed Induction Motor Based on Multiphysics Field Guowei Chen, Chong di, Xiaohua Bao, Member, IEEE, Wei Xu, Ran Zhu and

Jiaxin Li Digest ID: AU-09 School of Electrical Engineering & Automation, Emial:[email protected] University of Technology., Hefei, 230009

Summary - Taking a double-skewed induction motor as an example, the reference prototype uses the finite element method to perform three-dimensional multi-physics coupling calculations on the motor. Firstly, the three-dimensional electromagnetic field of the motor under the rated load is calculated. The loss density of the three-dimensional electromagnetic field node is used as the load, coupled to the three-dimensional temperature field model as the heat source, and boundary conditions are applied to simulate the steady-state temperature of the motor under the rated load. Then, the accuracy of the simulation calculation results is verified by the temperature rise experiment. Finally, take the temperature rise result of the rotor as the load, apply corresponding constraints, calculate and obtain the distribution of thermal stress of the rotor squirrel cage and the rotating shaft, find the position where the squirrel cage is easy to corrupted, and analyze the reason for the force.

I. Calculation of Electromagnetic Force A special equal slot fit is selected as the model of this article, because the equal slot fit best reflects the advantages of the double skewed rotor. ➢A. Prototype model

Heat transfer coefficient Solving model of the electromagnetic field ➢C. Steady-state temperature field simulation ➢B. Transient three-dimensional electromagnetic calculation

➢C. Calculation of Loss

Temperature distribution in rotor bar and shaft III. Calculation of Stress Field

II.Calculation of Steady Temperature Field ➢A. Temperature field model

Von-Mises stress distribution of the squirrel-cage and shaft

III. Conclusion •(1) The thermal stress of the bar is higher, and the thermal stress of the intermediate-ring is lower. The point of the maximum thermal stress appears at the junction of the bar and the end ring. This explains why the break of the Boundaries of solving region and Equivalent winding model bar is prone to occur here from the perspective of thermal stress. ➢B. Heat transfer coefficients •(2) The shaft of an ordinary induction motor is high in temperature due to the junction box is relatively closed and there is no heat poor heat dissipation. The double-skewed-slot rotor induction motor has a dissipation airflow inside, natural convection heat exchange is central ring and the central ring conductor is close to the shaft, resulting in a used here. higher temperature rise of the shaft of this type of motor, which leads to a higher possibility of failure of the shaft due to this eccentricity.

School of Electrical Engineering & Automation, Hefei University of Technology.