A speed calculation method for induction motor based on voltage decoupling control principle

A new simplified equivalent model of an induction motor is proposed in this paper, which is derived from the voltage decoupling control principle of induction motors. The model consists of two subsystems, the rotor flux and torque current subsystems, and is identical to that of a DC motor. According to this model, a speed calculation method is presented for a speed sensorless vector-controlled induction motor drive system, which uses integration of the difference between the command of torque current and the torque component of stator current. The validity of the proposed method is verified by computer simulation results.