This paper presents the design, analysis and verification of a 150 kW, 24 krpm high speed permanent magnet motor (HSPMM). The HSPMM is a two-pole motor with Gramme ring windings, which can shorten the end winding length and improve the rotor stiffness. The design procedure based on analytical methods, including the rotor mechanical design, magnetic design and cooling design is described. Then a prototype designed by the proposed design techniques is further verified by numerical methods including finite element analysis (FEA) and computational fluid dynamics (CFD) and experiments.

This paper investigates the electromagnetic and thermal performances of the open-circuit air cooled high-speed permanent magnet motor (HSPMM) with Gramme ring windings. Take a 36 kr/min, 75 kW HSPMM as an example, the electromagnetic losses, in particular the rotor eddy current loss and the stator iron loss of the motor are calculated. The influences of switching frequency and air gap length on these losses are studied. Then, a computational fluid dynamics (CFD) model is composed to calculate its coolant flow parameters and the temperature distribution. Based on the CFD results, a lumped-parameter thermal network (LPTN) is created and verified. Then, a 24 kr/min, 140 kW prototype with the same structure and cooling configuration is designed using the LPTN. Experiments show that the calculated results are with reasonable accuracy. Finally, a sensitivity analysis is applied to the 140 kW prototype based on the LPTN to disclose the influences of different parameters on the rotor permanent magnet temperature rise.