In this paper, the problem of tracking control for variable speed wind induction generator (IG) energy conversion system (WECS) is investigated using nonlinear predictive control. A rotor speed predictive control algorithm has been designed to control the angular speed of the machine in order to allow the WECS operate with maximum power extraction. The generator torque is estimated and injected into the control law to improve the tracking performance. Simulation is carried out to verify the performance of the control system.