Losses calculation and temperature field analysis of electrically excited brushless synchronous motor

Electrically excited brushless synchronous motor (EEBSM) is a kind of novel motor, and the operation mechanism of EEBSM is special. In addition to the fundamental component of waveforms of stator core and rotor core flux density change which is desired, and some undesired higher harmonic components appear which leading to relatively high losses and temperature rise. Taking an 11kW and 500r/min EEBSM with two different kinds of rotor structures as an example, first, the electromagnetic performance of EEBSM is calculated and analyzed using the finite element method. Secondly, in order to calculate accurately the core loss of EEBSM, an improved calculation model for the core loss is used. By means of Fourier analysis, the model consider the influences of alternating magnetic field, rotating magnetic field and skin effect. Finally, taking the losses obtained from the 2D electromagnetic analysis as the heat source. A finite element model of EEBSM for 3D temperature field analysis is established, and the temperature distribution of EEBSM under rated load is calculated.