This paper investigates the use of the method of inequalities （MoI） to design output-feedback compensators for the problem of the control of instabilities in a laminar plane Poiseuille flow. In common with many flow...This paper investigates the use of the method of inequalities （MoI） to design output-feedback compensators for the problem of the control of instabilities in a laminar plane Poiseuille flow. In common with many flows, the dynamics of streamwise vortices in plane Poiseuille flow are very non-normal. Consequently, small perturbations grow rapidly with a large transient that may trigger nonlinearities and lead to turbulence even though such perturbations would, in a linear flow model, eventually decay. Such a system can be described as a conditionally linear system. The sensitivity is measured using the maximum transient energy growth, which is widely used in the fluid dynamics community. The paper considers two approaches. In the first approach, the MoI is used to design low-order proportional and proportional-integral （PI） controllers. In the second one, the MoI is combined with McFarlane and Glover＇s H∞ loop-shaping design procedure in a mixed-optimization approach.展开更多
利用储能技术可以有效缓解、抑制电力系统的功率不平衡问题,提高电力系统运行水平。首先研究了结合储能设备和电力电子技术的并联储能型柔性交流输电(flexible AC transmission systems,FACTS)装置的潮流和暂态数学模型;然后在电力系统...利用储能技术可以有效缓解、抑制电力系统的功率不平衡问题,提高电力系统运行水平。首先研究了结合储能设备和电力电子技术的并联储能型柔性交流输电(flexible AC transmission systems,FACTS)装置的潮流和暂态数学模型;然后在电力系统分析综合程序中基于注入功率法建立了潮流的用户自定义模型,暂态建模则采用节点注入电流法;最后在美国电力科学研究院7节点实验系统中加入并联储能型FACTS装置,进行潮流和暂态稳定计算。结果表明,潮流计算的收敛性良好,自定义模型通过调节无功功率较好地控制了母线电压。暂态稳定计算中并联储能型FACTS装置较好地抑制了发电机的功角摆动,有效提高了电力系统稳定性。展开更多
文摘This paper investigates the use of the method of inequalities （MoI） to design output-feedback compensators for the problem of the control of instabilities in a laminar plane Poiseuille flow. In common with many flows, the dynamics of streamwise vortices in plane Poiseuille flow are very non-normal. Consequently, small perturbations grow rapidly with a large transient that may trigger nonlinearities and lead to turbulence even though such perturbations would, in a linear flow model, eventually decay. Such a system can be described as a conditionally linear system. The sensitivity is measured using the maximum transient energy growth, which is widely used in the fluid dynamics community. The paper considers two approaches. In the first approach, the MoI is used to design low-order proportional and proportional-integral （PI） controllers. In the second one, the MoI is combined with McFarlane and Glover＇s H∞ loop-shaping design procedure in a mixed-optimization approach.
文摘利用储能技术可以有效缓解、抑制电力系统的功率不平衡问题,提高电力系统运行水平。首先研究了结合储能设备和电力电子技术的并联储能型柔性交流输电(flexible AC transmission systems,FACTS)装置的潮流和暂态数学模型;然后在电力系统分析综合程序中基于注入功率法建立了潮流的用户自定义模型,暂态建模则采用节点注入电流法;最后在美国电力科学研究院7节点实验系统中加入并联储能型FACTS装置,进行潮流和暂态稳定计算。结果表明,潮流计算的收敛性良好,自定义模型通过调节无功功率较好地控制了母线电压。暂态稳定计算中并联储能型FACTS装置较好地抑制了发电机的功角摆动,有效提高了电力系统稳定性。
