Research of permanent magnets failure for high power-density interior PM synchronous motor used in electric vehicles

With the development of technology of power integration, high power-density PM motors have become researching hotspot in electric vehicles (E.V.) field. In this paper, researches have been carried out for the phenomena of magnets failure for high power-density interior PM synchronous motor used in electrical vehicles and the analysis of rotor iron losses have been performed. It has been found that eddy-current losses in the rotor magnets are the major reason for the failure. Furthermore, eddy-current losses are researched in the analytical and numerical ways, including the influence of division of magnets on the losses. Meanwhile, some prototype motors are researched in comparison.