Identification of Rotor Position and Current Dependent Flux Linkage Maps for EESMs

Flux linkages have proven to be suitable for electric machine modeling. Their identification from measurement is well-known for the permanent magnet synchronous machine (PMSM). However, electrically excited synchronous machines (EESMs) have an additional rotor winding and consequently an additional flux linkage, that has to be identified. The rotor flux linkage is crucial for modeling of the dynamic coupling between the stator and rotor. However, the fundamental of the rotor flux linkage cannot be identified from steady-state operation – as will be demonstrated in this work. Therefore, a strategy is proposed that injects a test voltage into an EESM with locked rotor thus identifying the flux linkages of the stator and the rotor.