Abstract
As development of hydrokinetic turbines advances, increasing focus is being placed on developing control strategies to meet a number of goals. These may be formulated to optimize performance, reduce loading, or maintain power at a constant value. The task of developing a controller invariably depends on knowledge of or the ability to identify a reliable model of system dynamics and stability. Such a model is necessary for numerical simulation of a turbine and controller. A dynamic system representing a hydrokinetic turbine can quickly grow in complexity when considering variants with many degrees of freedom (e.g., variable pitch, active yaw, gearing, variable speed generator). Dynamics are further complicated by the fact that a turbine’s output depends on a nonlinear relationship with an uncontrollable turbulent hydrokinetic resource (i.e., river, tidal channel, ocean current). However, the order of complexity can be reduced to a single degree of freedom (angular position of the turbine) when studying fixedpitch, direct drive, cross-flow designs.