With the increase in rotor diameter and hub height, a stiff tower design where the eigenfrequency lies above the rotor speed is often no longer the most economically viable solution. Instead, a soft tower design where the eigenfrequency crosses the rotor speeds during operation allows to save a lot of steel mass.
The make use of this benefit, the turbine controller must avoid resonant vibrations. With a fitting controller strategy, we can find an optimum eigenfrequency at which the fatigue stresses are minimized, maximizing material and cost savings.
- parameter study to find the optimum structural dynamics of the tower regarding fatigue loads
- modification of the control strategy of the turbine to avoid resonances
- verification of the control strategies by load simulations
- adaptation of the controller strategy on the turbine hardware and tests in cooperation with renowned partners in the wind industry
- iterative optimization of the tower with load simulation and structural analysis
- design solutions to further reduce vibrations such as dampers