Peak shaving strategy for load reduction of wind turbines based on model predictive control

Abstract

The protection control system determines the operation safety of wind turbines. The peak shaving controller can protect wind turbines by mitigating the thrust peak near the rated wind speed. However, the traditional controller is designed in the form of a look-up table, which leads to limitations in stability and regulation capability. Therefore, an improved strategy based on model predictive control is proposed to enhance the performance of peak shaving regulation. During each control period, the allowable pitch range is improved by solving the optimization problem in real-time. Firstly, the traditional peak shaving controller is introduced and analyzed in detail. Then, a peak shaving strategy based on model predictive control is put forward for thrust peak protection by providing additional pitch action. The controller is established in a closed-loop control framework by solving an open-loop optimization problem. Finally, systematic simulations are implemented based on a high fidelity model in Bladed. As a result, it is demonstrated that the strategy can reduce the thrust peak to the safe range at the expense of acceptable output power. In addition, the proposed controller can relieve the alternating load in the peak shaving range and mitigate fatigue loads of key components.

Keywords

• Wind turbine
• Peak shaving control
• Model predictive control
• Pitch control