Lumped Parameter Thermal Network Modeling and Analyzing for a 15 kW, 120000 rpm High-Speed Cage Solid Rotor Induction Motor

High-Speed Cage Solid Rotor Induction Motor (HSCRIM) features compact size and high power density, but it suffers from significant harmonic losses, concentrated temperature distribution, and limited cooling surface area, which makes heat dissipation challenging. In this paper, a multi-zone lumped parameter model for a 120,000 rpm HSCRIM is developed by taking into account the influence of the skin depth of higher-order harmonics, loss distribution, and mechanical structure. The thermal conductivity and heat transfer coefficients for each zone are theoretically derived, and a thermal network with 74 nodes is established to calculate the average temperatures of each motor component. The LPTN results are compared with FEA and CFD results, and the accuracy of the model is validated.