PREDICTIVE CONTROL STRATEGIES FOR VARIABLE SPEED WIND TURBINE WITH SATURATED INDUCTION GENERATOR

Abstract

This paper proposes a Model Predictive Control (MPC) scheme combined with rotor flux-oriented control principal for a self-exited induction generator driven by a variable speed wind turbine in a stand-alone system. The excitation of the autonomous squirrel cage induction generator is achieved by means of PWM inverter/rectifier with a single capacitor, where the saturation effect of the magnetic circuit of the induction generator is taken into account and modeled as a variable inductance as function of the magnetic current. Effective approaches are proposed, namely the switched and adaptive MPC, to take into account large variations of important parameters. The objective is to keep the DC voltage at the rectifier output and the rotor flux constant and equal to the reference value regardless of different disturbances, like wind speed, load and parameter uncertainties of the induction generator. A wide analysis and comparison of simulation results are provided to check the effectiveness of the proposed MPC controller under different operating conditions, also considering a variety of control options.