Simultaneous active control of tower lateral vibration and power control of wind turbine: A novel multivariable approach

Abstract

Lateral vibrations of the tower of a horizontal axis wind turbine is lightly damped and is vulnerable to induced vibration loads from wind. Such induced vibration load can decrease the fatigue life and increase the maintenance costs. Active vibration control using generator torque has been studied in previous research works but, there is a trade-off between reducing the lateral oscillations of the tower and fluctuations of output power, since any fluctuations in generator torque, in turn, causes fluctuations in the output power In this research, we illustrate a way that actively controls the lateral vibrations of the tower by using the generator torque but also simultaneously reduces fluctuations in the output power. We first, introduced a novel intelligent fuzzy torque control by measuring the lateral displacements of the tower and would receive feedback in the form of rotor speed error and its time derivative. On the basis of using this intelligence torque controller, we then introduced three-pitch control strategies to reduce output power fluctuations by considering the sliding mode theory. The simulation results demonstrate that the second strategy is extremely effective for reducing both lateral tower displacement and output power fluctuation.

Keywords

• Vibration load mitigation
• Multivariable control
• Wind turbine control
• Sliding mode theory