Multiple model multiple-input multiple-output predictive control for variable speed variable pitch wind energy conversion systems

A multivariable control strategy based on model predictive control techniques for the control of variable-speed variable pitch wind energy conversion systems (WECSs) in the above-rated wind speed zone is proposed. Pitch angle and generator torque are controlled simultaneously to provide optimal regulation of the generated power and the generator speed while minimising torsional torque fluctuations in the drive train and pitch actuator activity. This has the effect of improving the power quality of the electrical power generated by the WECS and increasing the life time of the mechanical parts of the system. Furthermore, safe and acceptable operation of the system is guaranteed by incorporating most of the constraints on the physical variables of the WECS in the controller design. In order to cope with the non-linearity in the WECS and the continuous variation in the operating point, a multiple model predictive controller is suggested to provide near optimal performance within the whole operating region.