Vedrana Spudić

Distributed low-complexity controller for wind power plant in derated operation

We consider a wind power plant of megawatt wind turbines operating in derated mode. When operating in this mode, the wind power plant controller is free to distribute power set-points to the individual turbines, as long as the total power demand is met. In this work, we design a controller that exploits this freedom to reduce the fatigue on the turbines in the wind power plant. We show that the controller can be designed in a decentralized manner, such that each wind turbine is equipped with a local low-complexity controller relying only on few measurements and little communication. As a basis for the controller design, a linear wind turbine model is constructed and verified in an operational wind power plant of megawatt turbines. Due to limitations of the wind power plant available for tests, it is not possible to implement the developed controller; instead the final distributed controller is evaluated via simulations using an industrial wind turbine model. The simulations consistently show fatigue reductions in the magnitude of 15-20%.

Explicit model predictive control for reduction of wind turbine structural loads

In many instances it is desirable for wind turbine to produce less power than is available in the wind. In such instances, one can balance between the strictness of the wind turbine power reference following and the reduction of the wind turbine structural loading. This paper investigates how wind turbine structural loads may be reduced through appropriate changes (i.e., small deviations) in wind turbine power references. An explicit model predictive controller - a closed form, parametric solution to the optimal control problem - is designed for the problem at hand. The extensive, realistic simulations have shown that the optimal controllers, which allow variation of the wind turbine power references, significantly reduce structural loads and fatigue.

Wind Farm Load Reduction via Parametric Programming Based Controller Design

Abstract We propose an optimization-based strategy for wind farm control. The objectives for the farm are to produce demanded power and to minimize the loads on mechanical parts of wind turbines that occur due to turbulent winds. The load reduction is achieved by dynamic adaptation of individual wind turbine power references to the current, turbulence induced, disturbances. However, the changes in operation of all wind turbines are coordinated to ensure that the wind farm produces power according to the grid operator demands. The pursued approach uses parametric programming to find the optimal control actions for the wind farm with respect to the constraints inherent to the system. The considered control design is also motivated by the need for efficient controller computation that will allow implementations on large wind farms.