Fast loss calculation and steady-state thermal analysis of a 120,000 rpm, 15 kW high-speed cage solid rotor induction motor

To enable fast and accurate thermal evaluation during the design stage of high-speed cage solid rotor induction motor (HSCRIM), a multi-zone model is proposed based on the structural and magneto-thermal characteristics, including a corresponding two-dimensional semi-analytical loss model (SALM) and a simplified lumped-parameter thermal network (SLPTN) model. The model also takes into account the reduction of effective conductivity caused by the end effect, the interaction between loss and temperature, and the change in the physical properties of steel and air at high temperatures. It employs a semi-analytical method to separately calculate the loss associated with the fundamental and harmonic magnetic fields, and uses a bidirectional iterative method between the loss model and the thermal network to achieve fast and accurate steady-state thermal analysis of the HSCRIM. The model is validated by finite element simulations performed under rated load condition and temperature rise tests under no load condition. The proposed model effectively reduces numbers of simulation samples and shortens the design time, providing a novel and practical method for the rapid design and optimization of HSCRIM.