Prediction of efficiency-optimized salient-pole synchronous machines´ operating range using a coupled numerical-analytical method

In this paper, a novel method for predicting the torque-speed characteristics of salient-pole synchronous machines (SPSM) is presented. These characteristics are commonly used as the basis for evaluating drives with variable operating ranges, e.g. traction drives for electric and hybrid electric vehicles. Such vehicles are often powered by permanent magnet synchronous machines (PMSM) which contain economically challenging rare earth materials. An interesting alternative to PMSMs are electrically excited synchronous machines which feature conventional materials and offer various advantages over PMSMs, such as lower losses in field weakening operation and the possibility to control the field excitation. To evaluate the use of SPSMs for different areas of application with wide operating ranges, a fast and precise method for prediction of the torque-speed characteristics is needed. For this reason a coupled numerical-analytical calculation method has been developed, combining the advantages of both approaches. The method is implemented into two software tools with different objectives. The calculation results of these two tools are compared to measurements of an industrial SPSM.