Increasing the Efficiency of Wind Turbines through Understanding of Their Transient Responses

全球对可再生能源的需求正在增加，而风力发电是增长最快的可再生能源。目前的风力涡轮机控制方法是为稳态风设计的，无法捕获湍流带来的额外能量。为了从非定常风中获取更多的能量，需要了解俯仰叶片上的复杂流动。该奖项支持基础研究，以了解风力涡轮机对随时间变化的风和叶片螺距的响应，促进为风力涡轮机创建新的控制律。该项目的研究目标是了解风力涡轮机对控制律和随时间变化的风和叶片桨距的瞬时响应。在湍流中，风力机的响应和控制律是相互关联的，必须作为一个完整的非线性、时变系统来处理。因此，了解控制律如何影响整个系统的响应是研究目标之一。为了实现研究目标，将在明尼苏达大学的大型闭式返回风洞设施中收集风力机叶片在非定常风和桨距条件下升力、阻力和力矩的称重传感器测量数据。由一台最大风速38米/S的变频器驱动的风机控制着风速。俯仰叶片角度将由电机控制在-2到4度的范围内。随时间变化的风和叶片变桨距运动输入的频率内容将覆盖风谱中感兴趣的范围。要研究的控制律包括基于力矩的控制和基于状态的控制。

Global demand for renewable energy is increasing, and wind power is the fastest growing source of renewable energy. Current control methods for wind turbines are designed for steady-state wind and are unable to capture the extra energy from turbulence. To capture more energy from unsteady wind, the complex flow over a pitching blade needs to be understood. This award supports fundamental research to understand wind turbine response to time-varying wind and blade pitch facilitating the creation of new control laws for wind turbines.The research objective of this project is to understand the transient response of wind turbines to control law and time varying wind and blade pitch. In turbulent flow, the wind turbine response and the control law are inter-connected and must be treated as a complete nonlinear, time-varying system. For this reason, understanding how the control law affects the overall system response is included in the research objective. To achieve the research objective, load cell measurements of lift force, drag force, and moment of wind turbine blades under unsteady wind and blade pitch conditions will be collected at the large closed return wind tunnel facility at the University of Minnesota. A fan driven by a variable frequency drive producing a maximum wind velocity of 38 m/s controls the wind speed. The pitch blade angle will be controlled by an electric motor in the range of -2 to +4 degrees. The frequency content of the time-varying wind and blade pitch motion inputs will cover the range of interest in the wind spectrum. Control laws to be investigated include torque-based control and state-based control.