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Robust Power Control of Wind Turbine with Smooth Switching between Operational Regions using a Two-mass Model

Nouriani, Ali | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51209 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Moradi, Hamed
  7. Abstract:
  8. Wind turbines have been the subject of many researches in recent decades. Optimization and continuous improvement of these systems play a decisive role in the development and exploitation of wind farms. Wind turbines can be studied from several aspects such as structure, dynamics, aerodynamics, electricity and control. In this research, robust power control of the wind turbine has been studied with emphasis on accurate 2 DOF mechanical and aerodynamic modeling. Aerodynamic coefficients of the turbine have been calculated using the numerical methods and the effect of this numerical modeling has been studied in comparison with the analytical methods on the turbine power control. Several new control methods have been introduced and a rather comprehensive comparison between these methods has been performed. In addition, the robustness of these methods has been investigated against the parametric uncertainty in turbine specifications as well as environmental parameters such as wind velocity and density. The other part of the study introduces a new strategy for smooth transition between the functional areas of the power controller in order to protect the wind turbine against the switching impulses. The smooth transition through adaptive hysteresis and middle-regions, reduces the impacts and shocks on the system. The hysteresis, in proportion to the variations in wind speed over a period of time, prevents unnecessary switching of the control mode. Also, the continuous generator torque trajectory in middle-regions reduces the impacts on the system during switchings. Modeling and simulations have been performed and validated by FAST software. Simulations show the significant effectiveness of aerodynamic modeling on the output power of the system. Also, the advantages and disadvantages of each of the different control methods of backstepping, sliding mode, H∞-Feedback Linearization (H∞-FL) and PI-Neural Network (PI-NN) are indicated. The transition strategy has smoothly reduced the number of controller switches and eliminates the impulses in the transition between regions without affecting the system efficiency
  9. Keywords:
  10. Wind Turbine ; Proportional-Integral (PI)Controller ; H-infinity Method ; Backstepping Algorithm ; Two Dimensional Model ; Aerodynamic Modeling Effect ; Smooth Transition

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