Control system on a wind turbine

Abstract

The aim for this project is to prepare a wind turbine controller and a wind turbine computer model suitable for controller development. The wind turbine is a Vestas V27, and the wind turbine drive train is modified by ChapDrive with a specified hydraulic transmission. Both the pitch and the rotor speed can be regulated for the modified wind turbine. The model is primarily based on a set of given wind turbine rotor characteristics, transmission specifications and transmission test data. The controller does not rely on an accurate wind speed gauge, since it can be difficult to realize. A control strategy was developed with special emphasis on energy efficiency for the modified wind turbine. Efficiency test data from the transmission prototype were only available for a limited operating range, so a final control strategy could not be confirmed for the whole operating range. Despite of the limited transmission efficiency data the traditional wind turbine control strategy including operation at a constant tip speed ratio is rejected. Calculations clearly show that the transmission efficiency is affecting how the wind turbine should be operated. The strategy includes details on how to ideally control the pitch and the rotor speed for different wind conditions. Following the strategy is realized without using an accurate wind gauge. The developed wind turbine controller was tested showing good results. It was tested against a turbulent wind model that is developed as a part of the project. The described controller concept could possibly be developed further for implementation in the modified Vestas V27. It should be stressed that alternative controller realization concepts should be considered before a final decision is made. Further work on this topic should be dedicated to clarify the ideal control strategy for the whole operating range of the wind turbine. This requires more information on the transmission prototype or a more accurate transmission model.