Multivariable H2 and H∞ control for a wind energy conversion system: a comparison
Journal of the Brazilian Society of Mechanical Sciences and Engineering
The Wind Energy Conversion System (WECS) is a nonlinear system, highly dependent on a stochastic variable characterized by sudden variations, and subjected to cyclical disturbances caused by operational phenomena. Thus, the quality of a WECS controller is measured by its capacity to deal with unmodeled dynamics, stochastic signals, and periodic, as well as non-periodic disturbances. Since the WECS' objectives can be easily specified in terms of maximum allowable gain in the
... isturbance-to-output transfer functions, H 2 and H ∞ methodologies can be good options for designing a WECS stabilizing controller, combining specifications such as: disturbance attenuation, asymptotic tracking, bandwidth limitation, robust stability, and trade-off between performance and control effort. Designs for WECS multivariable feedback controllers based on H 2 and H ∞ methodologies are presented in this paper. The performances of both controllers are computationally simulated, analyzed and compared in order to identify the advantages and drawbacks of each controller design. A nonlinear model of a WECS with suitable complexity was developed for computational simulations. Five distinct WECS subsystems are considered in this modeling: wind, aerodynamics, drive train, pitch actuator and generator.