LQG and Gaussian process techniques: For fixed-structure wind turbine control

Wind turbines are growing bigger to becomemore cost-efficient. This does increase the severity of the vibrations that are present in the turbine blades, both due to predictable effects like wind shear and tower shadow, and due to less predictable effects like turbulence and flutter. If wind turbines are to become bigger and more cost-efficient,...

Robust lidar-based closed-loop wake redirection for wind farm control

Wind turbine wake redirection is a promising concept for wind farm control to increase the total power of a wind farm. Further, the concept aims to avoid partial wake overlap on a downwind wind turbine and hence aims to decrease structural loads. Controller for wake redirection need to account for model uncertainties due to the complexity of...

Active power control of waked wind farms

Active power control can be used to balance the total power generated by wind farms with the power consumed on the electricity grid. With the increasing penetration levels of wind energy, there is an increasing need for this ancillary service. In this paper, we show that the tracking of a certain power reference signal provided by the...

Assessing the Severity of Wind Gusts with Lidar

Lidars have gained a lot of popularity in the field of wind energy, partly because of their potential to be used for wind turbine control. By scanning the oncoming wind field, any threats such as gusts can be detected early and high loads can be avoided by taking preventive actions. Unfortunately, lidars suffer from some inherent weaknesses that...

Control design for two-bladed wind turbines

In the past decades wind energy has evolved into a mature source of sustainable energy such that onshore wind turbines have become cost competitive with other fossil-based energy sources. Onshore wind energy, however, faces social resistance and a lack of available locations. Offshore wind energy, on the other hand, offers vast amounts of...

Data-driven wind plant control

Each wind turbine in a cluster of wind turbines (a wind power plant) can influence the performance of other turbines through the wake that forms downstream of its rotor. The wake has a reduced wind velocity, since the turbine extracts energy from the flow, and the obstruction by the wind turbine rotor causes increased turbulence. If another...

Grid support by power electronic converters of distributed generation units

An increasing number of small Distributed Generation (DG) units are connected to the grid. The introduction of DG causes several problems, which are mainly related to the differences between DG units and conventional generators. Four problems have been considered in this thesis: damping of harmonics, voltage control, the behaviour of DG units...