Influence of WFSM Parameters, Currents and Control Scheme on Its Dynamic Performance During Active Short Circuit Fault in EV

Drive initiated active symmetrical short circuit (SSC) of motor phases is used as a protection method in electric vehicle (EV) drives during abnormalities. This paper exclusively investigates the effects of wound field synchronous machine (WFSM) stator and field circuit parameters, currents and control methods on its dynamic performance during a forced SSC fault. This paper employs a novel coupled circuit-based control model that represents the stator subsystem in two-axis model and the field exciter and rotor circuit as physical variables to capture the transient response during freewheeling action towards predicting both steady-state and transient responses of a WFSM to 3-phase SSC faults. Stator non-linear inductances, resistances, stator current angle, field current magnitude, and rotor field winding parameters are included in the model, thus making it comprehensive for performance analysis in WFSMs. Behavior of stator and rotor currents during SSC is analyzed at different pre-fault conditions when the WFSM is controlled using total- and rotor-loss minimization control schemes. Results obtained using the developed model are verified and compared with results obtained from numerical simulations based on finite element model and experimental tests conducted on the test machine.