The paper compares the performances of several adaptive rotor flux and speed estimation methods used in speed sensorless vector control of induction motor. First, a short review of Luenberger, Gopinath, MRAS, Torque Error MRAS and Kalman Filter estimation methods is presented. Then, the vector control drive using each estimation principle is simulated, using the real-time simulation techniques. The simulation results are compared and discussed by means of stability, sensitivity to parameter variation and operation in the low speed region, taking also into account the impossibility to estimate without any error both speed and rotor resistance, when the rotor equations are used as reference or adjustable model in estimation.