Wind Turbine Simulation in Dymola

Abstract

Modvion is building and developing towers made of timber, for modern commercial wind turbines reaching hub heights of 150 meters and above. Such wind turbines are machines with large flexible structures that need to handle turbulent wind loads. When designing and verifying the structural components, the interaction between structural dynamics, aerodynamics, the mechanical, electrical and control systems need to be considered. To achieve this, an aero-elastic model is used. The purpose of this project is to create a tool for such aero-elastic simulations of horizontal axis wind turbines, in the modelling and simulation environment Dymola. The tool should be capable of running all simulations needed for the design and dimensioning of the structural components of a wind turbine and enable flexibility in terms of increasing or decreasing complexity of the simulations. The tool was built up using many of the predefined components in the Modelica libraries while some of the more complex components were coded from scratch. The accuracy of the tool was verified by running simulations on two wind turbine models, the NREL 5MWbenchmark turbine and the research turbine on Björkö with a wooden tower constructed by Modvion. The verification was performed by running simulations with the Dymola tool and comparing the results with simulations made with the acknowledged softwares, FAST and Vidyn. Three different types of load cases are included, the Ramp case, the Extreme Operating Gust case and Turbulent cases. A few studies were then performed on the Björkö turbine model to study what effect that different phenomena and design changes might have on the wooden tower structure. It could be concluded that it is possible to create a tool for aero-elastic simulations of horizontal axis wind turbines in Dymola and that such a tool enables