Permanent magnet synchronous motors are often used in hybrid electric vehicles due to the high power density. Overheating in a PMSM motor can cause negative effects on the work of permanent magnets and a significant shortening of the life of the machine due to the phenomenon of the thermal ageing of insulation. Therefore, it is extremely important to know the exact temperature distribution in different parts of the electrical machine under various operating conditions. This paper presents a lumped parameter thermal model and FE model of a permanent magnet synchronous motor. A method for the homogenization of a stator winding is also described. In order to validate the accuracy of the calculation results, measurements on the physical model of the machine were carried out.