Rotor time constant updating scheme for a rotor flux-oriented induction motor drive

This paper presents a simple on-line rotor time constant identification sch eme of an indirect field-oriented induction motor for the purpose of improv ing the performance and robustness of the drive. The proposed technique nei ther requires any special test signal nor any complex computations. This sc heme is based on a special switching technique of the current-regulated pul sewidth modulation (CRPWM) voltage-source inverter (VSI), which allows meas uring the induced voltage across the stator phase, The rotor time constant is then identified directly from this measured voltage, This proposed techn ique pro,ides six windows within one electric cycle to update the rotor tim e constant, which should be sufficient far all practical purposes. Simulate d results followed by experiments are presented to validate the effectivene ss of the proposed technique.