Speed and rotor resistance estimation for torque control of an induction motor

A speed sensorless controller of an induction motor (IM) with rotor resistance estimation is presented. In the controller design only the stator current and voltage signals are assumed to be measurable. The rotor resistance and speed estimates are obtained as a solution of a linear algebraic system with pseudo current and voltage signals and their observable derivatives as inputs. The proposed scheme works in all IM operational modes and it can also be used for real-time IM tuning if the speed signal is available. The validity of the proposed method is verified by simulation and experimental results