The increased size and flexibility of modern multi-Megawatt wind turbines has resulted in the dynamic behaviour of these structures becoming an important design consideration. The aim of this paper is to study the variation in natural frequency of wind turbine blades due to centrifugal stiffening and the potential use of semi-active tuned mass dampers (STMDs) in reducing vibrations in the flapw...

Faults of wind turbine generator electromechanical parts are common and very expensive. This paper introduces a generator fault-tolerant control scheme for variable-speed variable-pitch wind turbines that can be applied regardless to the AC generator used. The focus is on generator stator isolation inter-turn fault that can be diagnosed and characterised before triggering the safety device. An ...

One of the disadvantages in Connection of wind energy conversion systems (WECSs) to transmission networks is plentiful turbulence of wind speed. Therefore effects of this problem must be controlled. owadays, pitch-controlled WECSs are increasingly used for variable speed and pitch wind turbines. Megawatt class wind turbines generally turn at variable speed in wind farm. Thus turbine operation m...

Wind is the fastest growing renewable energy source, increasing at an annual rate of 25% with a worldwide installed capacity of 74 GW in 2007. The vast majority of wind power is generated from onshore wind farms. Their growth is however limited by the lack of inexpensive land near major population centers and the visual pollution caused by large wind turbines. Wind energy generated from offshor...

During recent years renewables have been acquiring gradually a significant importance in the world market (especially in the Spanish energetic market) and in society; this fact makes clear the need to increase and improve knowledge of these power sources. Starting from the results of a Life Cycle Assessment (LCA) of a multi-megawatt wind turbine, this work is aimed to assess the relevance of di...

Wind turbines are usually installed on remote locations and in order to increase their economic competence malfunctions should be reduced and prevented. Faults of wind turbine generator electromechanical parts are common and very expensive. This paper proposes a fault-tolerant control strategy for variable-speed variable-pitch wind turbines in case of identified and characterised squirrel-cage ...

The introduction of photovoltaic and wind turbine generation systems has been accelerating around the world, and the case for using renewable energy remains strong. However, because of the intermittency of the renewable sources, the power generation level, or capacity factor, of these renewable energy systems is relatively low and the generation level is not fixed. Generation capacity with thes...

This paper proposes to work on power flow system for a wind turbine comprising a grid connected through Permanent Magnet Synchronous Generator and a power converter where it is employed as the bridge between the generator and the grid for megawatt power generation. At this power level, current source converter (CSC) topology possess favourable features such as simple structure grid friendly wav...

This paper presents a review of over a decade of research on Vertical Axis Wind Turbines (VAWTs) conducted at Uppsala University. The paper presents, among others, an overview of the 200 kW VAWT located in Falkenberg, Sweden, as well as a description of the work done on the 12 kW prototype VAWT in Marsta, Sweden. Several key aspects have been tested and successfully demonstrated at our two expe...

For the development of the next generation of multi megawatt wind turbines, advanced control concepts are one of the major tasks. Reduction of fatigue and extreme loading could help to improve the overall design process and make plants more cost effective. This work deals with the application of the promising methodology of feedforward control using nacellebased lidar sensor measurements on a 1...