Systematic Approach to Design, Modeling and Characterization of Externally Excited Synchronous Machines for Traction Applications

To evaluate the use of an externally excited synchronous machine (EESM) in electric vehicles, a thorough understanding of the machine's operating characteristics is essential. The influence of the high magnetic saturation, complex field distribution and cross-coupling effects should not be ignored when designing an EESM. The variation of the machine parameters, such as inductances, can affect the torque estimation and consequently the control accuracy. This paper deals with preliminary design and modeling of an EESM, highlighting the non-linear characteristics of the machine. Based on these characteristics, the set point current profiles are computed and an efficiency map is predicted.