Magnetic Characteristic Analysis of Applying Grain-Oriented Electrical Steel on Traction Motors

In this paper, magnetic properties analysis of applying grain-oriented electrical steel (GO) to the traction motors for battery electric vehicle (BEV) and hybrid electric vehicle (HEV) is conducted. For the purpose of enhancing the power characteristic of the motor, GO is applied to the stator tooth, as the magnetic flux path of the tooth part is relatively uniform at radial direction. The comparison models of each applications have the same structure and only the tooth material is changed to conduct the performance comparison under the equivalent current conditions. In particular, the specifications of the test operating points, such as speed and torque, were separately determined considering the driving characteristics of each application. A detailed analysis of the GO application effect of both models was carried out according to the current density and rotation speed, and the iron loss, torque, and efficiency at each test point were compared. Due to the narrow operating speed range and lower maximum speed of the HEV and superior magnetic characteristics of the GO, the HEV showed larger iron loss reduction ratio, torque increasement, and efficiency increasement compared with BEV.