Full Envelope Wind Turbine Control Systems Design

风力涡轮机是一种提供清洁、安全和丰富能源的手段。它对环境的影响有限，运营成本低。另一方面，风力涡轮机的初始资本成本很高。因此，长寿命和可预测的运行模式是可取的。这项*建议旨在通过完全*包络控制提高风力涡轮机的运行寿命和可预测性。风力涡轮机在两种模式下运行：一种是中等风速，其目标是*获取最大功率；另一种是较高风速，其功率被调节到接近最大功率。在中等风速和较高风速之间的*转换过程中，系统应该有效和安全地在*风速之间移动。大多数大型风力涡轮机采用变速、变桨距配置*，其中使用了两种驱动方式：发电机定子的励磁，作为制动力*控制旋转；以及叶片螺距，它影响气动升力、阻力和所产生的力。*为了降低运营成本，尽可能避免叶片的俯仰，因为这涉及需要润滑的机械部件和有限寿命的轴承。因此，在中等*风速时，仅使用现场激励，而在功率调节模式下，同时使用叶片俯仰和*现场激励。从一种状态转换到另一种状态涉及执行器数量的变化，以及控制系统目标和动态特性的变化。在过渡区域，涡轮的超速可能会导致叶片和塔架结构中的轴承、扭矩和力超过额定条件。所有这些问题都会极大地*降低预期寿命并增加维护成本。*有希望的风力机反馈控制方法包括线性参数变化概念、*优化干扰抑制方法和模型预测控制。此外，切换系统*将允许更灵活地处理不同的目标、执行器的数量和不同的*动态。这里的工作将考虑这些方法的外推，以处理过渡区*控制和涡轮机的全包络运行。状态之间的转换可能会导致速度和扭矩的*振荡，还会增加变桨距执行器的磨损。智能地选择*控制策略以避免非线性振荡将有利于实际实施。*寻找峰值功率充满困难。叶片磨损和损坏导致的动态变化、*不确定的功率曲线数据以及涡轮机之间和与环境的复杂相互作用*可能会导致在估计最大功率提取参数时出现错误。采用本方案中描述的先进的*反馈控制技术可以提高效率、最大*功率提取并延长涡轮机的寿命。

Wind turbines are a means of providing clean, safe and abundant energy. There is limited***environmental impact and the operating costs are low. On the other hand, initial capital costs for***wind turbines are high. As such, long life and predictable operating patterns are desirable. This***proposal aims to improve the life and predictability of operation of wind turbines through full***envelope control. Wind turbines operate in two regimes: moderate wind speeds where the goal is to***extract maximum power and higher wind speeds where power is regulated near capacity. In the***transition between moderate and higher wind speeds the system should efficiently and safely move***between regimes. Most large wind turbines are of a variable speed, variable pitch configuration***where two actuations are used: field excitation of the generator stator, governing rotation as a***braking force; and blade pitch, which affects the aerodynamic lift and drag and generated forces.***For lower operating costs, pitching of the blades is avoided as much as possible as this involves***mechanical components requiring lubrication and bearings with finite lifespans. Thus, at moderate***wind speeds only field excitation is used, while in power regulation mode, both blade pitching and***field excitation are employed. Transitioning from one regime to the other involves a change in the***number of actuators, along with changes in control system goals and in dynamic characteristics. In***the transition region, overspeeding of the turbine can result in exceeding rated conditions for***bearings and torques and forces in the blades and tower structure. All of these issues can greatly***reduce the life expectancy and increase maintenance costs.***Promising methods for feedback control of wind turbines include linear parameter varying concepts,***optimized disturbance rejection methods and model predictive control. Further, switched systems***will allow more flexibility in dealing with varying objectives, number of actuators, and varying***dynamics. Work here will consider the extrapolation of these methods to handle transition region***control and full envelope operation of the turbine. Transition between regimes can induce***oscillations in speed and torques and also increase wear on the pitch actuators. Intelligent choices of***control strategy to avoid nonlinear oscillations would be of benefit to practical implementation.***Finding peak power is fraught with difficulty. Varying dynamics due to blade wear and damage,***uncertain power curve data, and complex interaction between turbines and with the environment***can cause errors in estimating parameters for maximum power extraction. Employment of advanced***feedback control techniques as described in this proposal can improve the efficiency, maximum***power extraction and improve life of the turbine.