Analysis of multi-field coupled air friction loss and temperature field of high-speed permanent magnet machine

The high-speed rotation of the high-speed permanent magnet machine (HSPMM) causes high air friction loss. The multi-field calculation of air friction loss is usually unidirectional coupling, so the interaction between temperature and air friction loss cannot be considered. By using the improved analytical model, the air friction loss considering the effect of temperature on air density and dynamic viscosity is calculated. The influence of this method on the temperature and air velocity of the machine is compared. The accuracy of this method is verified by comparing with the improved air friction loss numerical calculation model. The results show that the improved calculation model of air friction loss is more accurate.