Speed sensorless vector control of induction motors with parameter estimation

A novel rotor velocity estimation scheme applicable to vector controlled induction motors has been described. The proposed method evaluates rotor velocity, ω_r, online, does not require any extra transducers or injection of any signals, nor does it employ complicated algorithms such as MRACS or Kalman filters. Furthermore, the new scheme operates at all velocities including zero with very little error. The procedure employs motor model equations; however all differential and integral terms have been eliminated giving a very fast, low-cost, and practical alternative to methods currently available. Furthermore, the resistance estimation technique is also implemented. Not only does this ensure the tuned operation of the vector controller, but also results in the aforementioned velocity estimator being completely parameter insensitive. A detailed and thorough explanation of the underlying theory of both velocity and parameter estimation techniques is given. These are supported by various simulation tests, taking into consideration the PWM inverter, and practical results