Full Envelope Wind Turbine Control Systems Design

风力涡轮机是提供清洁、安全和丰富能源的一种手段。对环境的影响有限，运营成本也很低。另一方面，风力涡轮机的初始资本成本很高。因此，长寿命和可预测的操作模式是可取的。该方案旨在通过全面控制来提高风力发电机的寿命和运行的可预测性。风力涡轮机在两种状态下运行：中等风速，其目标是提取最大的功率；较高的风速，其功率被调节到接近容量。在中等和较高风速之间的过渡中，系统应该有效和安全地在不同的制度之间移动。大多数大型风力涡轮机都是变速，变螺距配置，其中使用两个驱动：发电机定子的励磁，作为制动力控制旋转；而桨距，会影响气动升力和阻力并产生力。为了降低运行成本，尽可能避免叶片的俯仰，因为这涉及到需要润滑的机械部件和寿命有限的轴承。因此，在中等风速下仅使用场激励，而在功率调节模式下，桨叶俯仰和场激励同时使用。从一种状态过渡到另一种状态涉及到执行器数量的变化，以及控制系统目标和动态特性的变化。在过渡区域，涡轮的超速会导致叶片和塔架结构中的轴承和扭矩和力超过额定条件。所有这些问题都会大大降低预期寿命，增加维护成本。风电机组的反馈控制方法有线性参数变化概念、最优抗扰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，执行器数量和动态变化。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线运行。制度之间的过渡会引起速度和扭矩的振荡，也会增加俯仰致动器的磨损。智能选择控制策略以避免非线性振荡将有利于实际实现。寻找峰值功率充满了困难。由于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与环境之间复杂的相互作用，都会导致最大功率提取参数的估计误差。采用先进的反馈控制技术，如在这个建议中所述，可以提高效率，最大功率提取和提高寿命的涡轮机。

Wind turbines are a means of providing clean, safe and abundant energy. There is limitedenvironmental impact and the operating costs are low. On the other hand, initial capital costs forwind turbines are high. As such, long life and predictable operating patterns are desirable. Thisproposal aims to improve the life and predictability of operation of wind turbines through fullenvelope control. Wind turbines operate in two regimes: moderate wind speeds where the goal is toextract maximum power and higher wind speeds where power is regulated near capacity. In thetransition between moderate and higher wind speeds the system should efficiently and safely movebetween regimes. Most large wind turbines are of a variable speed, variable pitch configurationwhere two actuations are used: field excitation of the generator stator, governing rotation as abraking 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 involvesmechanical components requiring lubrication and bearings with finite lifespans. Thus, at moderatewind speeds only field excitation is used, while in power regulation mode, both blade pitching andfield excitation are employed. Transitioning from one regime to the other involves a change in thenumber of actuators, along with changes in control system goals and in dynamic characteristics. Inthe transition region, overspeeding of the turbine can result in exceeding rated conditions forbearings and torques and forces in the blades and tower structure. All of these issues can greatlyreduce 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 systemswill allow more flexibility in dealing with varying objectives, number of actuators, and varyingdynamics. Work here will consider the extrapolation of these methods to handle transition regioncontrol and full envelope operation of the turbine. Transition between regimes can induceoscillations in speed and torques and also increase wear on the pitch actuators. Intelligent choices ofcontrol 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 environmentcan cause errors in estimating parameters for maximum power extraction. Employment of advancedfeedback control techniques as described in this proposal can improve the efficiency, maximumpower extraction and improve life of the turbine.