Megawatt high-speed permanent magnet (HSPM) machine has a series of thermal problems, such as high loss density, difficult heat dissipation, high temperature rise. Due to a long time consumed in modeling and dissection of the finite element method in the early stage, it is not suitable for the rapid parametric calculation and analysis of thermal performance. Therefore, for a 1MW axial and radial hybrid ventilation HSPM machine, the lumped parameter thermal network (LPTN) method is applied in this paper to realize the rapid parameter modeling, and accurately obtain the machine temperature rise while ensuring the calculation speed. Firstly, based on the relevant theories of heat transfer, considering the influence of loss distribution and cooling medium flow state on temperature rise, the physical model of fluid domain is established using CFD method, and the fluid medium characteristics are solved and analyzed. Then, the 2D thermal network model of the machine is established, and the temperature rise is obtained by using the LPTN method. Moreover, the axial and radial temperature rise distribution of the machine are analyzed, and the influence of fluid cooling performance on the temperature rise is clarified. Finally, the temperature rise experiment of the prototype is carried out to verify the accuracy of the calculation results. The conclusion is valuable for the design and thermal performance optimization of HSPM machine.

high-speed permanent magnet machine, thermal network method, cooling structure, fluid field, temperature field.