Adaptive control design and implementation for collective pitch in wind energy conversion systems

Area of Science:

• Engineering
• Control Systems
• Renewable Energy

Background:

• Variable speed, variable pitch wind turbines require advanced control for optimal performance, especially during high wind speeds.
• Traditional gain-scheduled PI controllers often struggle with model uncertainties and achieving consistent stability and performance.
• Collective pitch control is crucial for managing generator speed and power output in wind turbines.

Purpose of the Study:

• To design and evaluate a discrete-time L1 adaptive controller for collective pitch control in variable speed, variable pitch wind turbines.
• To demonstrate the controller's robustness against model uncertainties and guarantee closed-loop system stability and performance.
• To validate the controller's applicability and superior performance in real-time applications through simulation and hardware-in-the-loop testing.

Main Methods:

• A discrete-time L1 adaptive control algorithm was developed for regulating blade pitch angles.
• The proposed controller was simulated using a 5-MW offshore wind turbine model.
• Hardware-in-the-loop testing was performed using a reduced-scale wind turbine emulator and laboratory equipment.

Main Results:

• Simulations showed the L1 adaptive controller significantly outperformed the conventional gain-scheduled PI controller.
• Experimental results from hardware-in-the-loop testing validated the enhanced closed-loop system performance.
• The controller demonstrated robustness against wind turbine model uncertainties and real-time implementation feasibility.

Conclusions:

• The discrete-time L1 adaptive controller offers a robust and effective solution for collective pitch control in wind turbines.
• This advanced control strategy enhances generator speed and power regulation, outperforming traditional PI controllers.
• The controller's proven performance and feasibility pave the way for its adoption in real-world wind energy systems.