Temperature rise calculation of high speed PM machine based on thermal-circuit method and 3D fluid field method

The high speed permanent magnet (PM) machine has been widely investigated since it has small size, high efficiency and high power density. In this paper, a high speed PM machine with rated speed of 60000r/min is studied and the parameters of equivalent thermal-circuit are calculated on the basis of computational fluid dynamics. Then, the temperature rise is calculated by using 3D finite element method and thermal circuit method based on the machine losses determined by the field-circuit coupled analysis. The calculated temperature rises of the machine by equivalent thermal circuit method and 3D finite element method are compared respectively with the tested results.