Methods for Increasing Region 2 Power Capture on a Variable Speed HAWT: Preprint

The standard region 2 control scheme for a variable speed wind turbine, tc = kw2, has several shortcomings that can result in significant power loss. The first of these is that there is no accurate way to determine the gain k; modeling programs are not accurate enough to represent all of the complex aerodynamics, and these aerodynamics change over time. Furthermore, it is not certain whether thevalue of k used in the standard control even provides for the maximum energy capture under real-world turbulent conditions. New control ideas are introduced to address these issues. First, it is shown in simulation that using smaller values of k than the standard can result in increased power capture. Second, an optimally tracking rotor control scheme improves upon the standard scheme byassisting the rotor speed in tracking wind speed fluctuations more rapidly. Finally, an adpative control scheme is proposed that allows for maximum power capture despite parameter uncertainty.