ABSTRACT Coordinated controllers for coal-fired ultra-supercritical (USC) boiler-turbine power units in the new flexible-operation mode face many challenges, such as faster load-following rate over wider-range operations, nonlinear dynamics with long time delay and multiple disturbances from strong-coupled multivariable processes. Hence, to improve the coordinated controller of the USB power unit, this paper proposes an internal-model robust adaptive control (IM-RAC) approach to handle nonlinearity, multiple variables, unknown uncertainties and long-time delay. The proposed IM-RAC augments an internal model with the framework of an L1 robust adaptive control to predict the time-delay variable. In addition, the proposed IM-RAC uses a dual-feedback adaptive law instead of a single-feedback adaptive law. Based on the proof by contradiction, the stability of the IM-RAC control loop is proved, and stability conditions and performance bounds are derived. Furthermore, an IM-RAC coordinated controller is designed for a 1000 MW coal-fired USC power unit. By simulations, we show that the proposed IM-RAC outperforms an advanced model predictive controller in the presences of fast and wide load-following, long-time delay and uncertainties. With less modelling requirements, the IM-RAC control approach is a promising solution to improve the operational flexibility of USC power units.

中文翻译：

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改进的内模型鲁棒自适应控制及其在灵活运行中的 USC 锅炉-涡轮发电机组协调控制中的应用

摘要 新型柔性运行模式下燃煤超超临界 (USC) 锅炉-汽轮发电机组协调控制器面临着许多挑战，例如在更宽范围运行中更快的负荷跟随率，长延迟和多次响应的非线性动力学。来自强耦合多变量过程的干扰。因此，为了改进USB电源单元的协调控制器，本文提出了一种内模鲁棒自适应控制（IM-RAC）方法来处理非线性、多变量、未知不确定性和长时间延迟。所提出的 IM-RAC 使用 L1 鲁棒自适应控制框架增强了内部模型，以预测时延变量。此外，提出的 IM-RAC 使用双反馈自适应律而不是单反馈自适应律。根据反证法，证明了 IM-RAC 控制回路的稳定性，并推导出稳定性条件和性能界限。此外，IM-RAC 协调控制器是为 1000 MW 燃煤 USC 发电机组设计的。通过仿真，我们表明所提出的 IM-RAC 在存在快速和宽负载跟随、长时间延迟和不确定性的情况下优于先进的模型预测控制器。由于建模要求较少，IM-RAC 控制方法是提高 USC 动力装置操作灵活性的有前途的解决方案。我们表明，在存在快速和广泛的负载跟随、长时间延迟和不确定性的情况下，所提出的 IM-RAC 优于先进的模型预测控制器。由于建模要求较少，IM-RAC 控制方法是提高 USC 动力装置运行灵活性的有前途的解决方案。我们表明，在存在快速和广泛的负载跟随、长时间延迟和不确定性的情况下，所提出的 IM-RAC 优于先进的模型预测控制器。由于建模要求较少，IM-RAC 控制方法是提高 USC 动力装置运行灵活性的有前途的解决方案。