基于事件触发控制的时滞电力系统负荷频率控制

区域电网间存在较高的数据传输,使有限的通信和计算资源变得拥塞。为降低区域电网间的通信负担,提出基于事件触发控制的时滞电力系统负荷频率控制(LFC)方法。针对具有通信延迟的LFC系统,建立基于事件触发控制的时滞LFC动态模型。进而采用多求和不等式,提出具有事件触发控制器的时滞相关LFC系统Lyapunov稳定分析判据;在此基础上,推导了基于事件触发通信和输出反馈的负荷频率控制器协同设计方案,以保证电力系统频率稳定性的同时提高数据传输效率。仿真结果表明,所提方法能够有效减小互联系统频率和联络线功率振荡,保证系统的时滞稳定性并减少网络通信的冗余传输。     

基于事件触发的电力系统H∞优化控制

针对大规模集中用电导致电力系统负荷端激增从而影响电力系统稳定性的问题,提出一种基于事件触发的H_∞优化控制方式。本文采用扇区法对单机无穷大电力系统进行线性化处理,之后通过模糊逻辑建立电力系统的T-S模糊模型。通过事件触发理论和模糊逻辑利用并行分布补偿(parallel distribution compensation,PDC)的方法设计系统控制器。H∞优化控制相比于传统的控制方法提高了系统的稳定性及抗干扰能力,因此本文根据李雅普诺夫稳定性理论和H∞优化控制理论,基于线性矩阵不等式(linear Matrix Inequality,LMI),给出了保证单机无穷大电力系统闭环渐进稳定的充分条件,并采用MATLAB仿真软件对系统进行仿真,从而证明稳定条件的存在。     

基于OVAC的IPC和励磁作用提高暂态稳定研究

针对发电机励磁和相间功率控制器(IPC)对电力系统稳定性的影响,提出了通过相间功率控制器和发电机励磁系统共同作用提高系统暂态稳定性。基于单机无穷大系统的非线性模型,建立了包含励磁系统参数和相间功率控制器控制参数的状态空间方程,并基于最优变目标控制(OVAC)策略,可以得出以励磁系统为基础加以IPC协调的控制规律,通过仿真分析,可以验证该策略能够有效提高系统的暂态稳定性。     

网络控制系统的事件触发与量化控制协同设计

针对信道带宽受限的无线网络控制系统(NCSs),提出了包含事件触发机制、信号量化和状态反馈L2控制的协同设计方法.首先,针对无线网络时变延时,提出一种事件触发机制,并建立了线性系统的量化控制数学模型.其次,基于该模型,并利用李亚普若夫泛函和线性矩阵不等式方法,证明了系统时滞独立的L2量化控制的稳定性,并给出了求解事件触发器参数和L2量化控制的协同设计方法.最后,通过仿真验证了所提方法的有效性.     

事件触发网络化控制系统在攻击下的稳定性分析

以存在网络延迟的NCSs为研究对象,结合事件触发机制,研究遭受拒绝服务攻击(DoS)的NCSs稳定性问题。在DoS攻击过程中,NCSs的传感器无法接收测量信息或者执行器无法获取控制信息,会存在不稳定的子系统。为了提高NCSs的稳定性,首先,把存在网络时延和DoS攻击的NCSs系统建模成包含稳定子系统和不稳定子系统的闭环切换系统模型;接着,基于切换系统分析方法,得到该系统指数稳定的充分条件;进一步,分析DoS攻击的时间比率,只要DoS攻击时间比例在有效范围,不论DoS攻击如何作用于系统,总能保证该系统的指数稳定性。实验结果表明,当0δ3时,网络控制系统能获得相应的指数稳定性,验证了此方法在DoS攻击下,具有事件触发机制NCSs稳定的有效性。     

基于事件触发的永磁同步电机多步模型预测转矩控制

针对多步模型预测控制(MPC)计算量大的问题,将事件触发机制引入到永磁同步电机(PMSM)多步模型预测转矩控制(MPTC),建立基于转矩误差、磁链误差和连续触发次数的事件触发机制。当满足事件触发条件时,相应的采样周期无需多步预测计算,可从已有的控制序列中选择对应的电压矢量。仿真结果表明,基于事件触发的PMSM MPTC可行,由于事件触发时,牺牲滚动优化的特性,转矩和磁链脉动轻微增大,开关频率和平均运算量有所降低。     

TCIPC提高系统稳定性的逆系统方法最优控制

可控相间功率控制器(TCIPC)对电力系统潮流控制,提高线路输送能力具有一定的作用,在研究可控相间功率控制器(TCIPC)基本原理的基础上,分析了电感、电容支路对带TCIPC联络线传输功率的控制特性,进行了TCIPC提高系统暂态稳定性的机理分析。基于逆系统方法,将含调谐型TCIPC的非线性电力系统线性化,构造出一个伪线性系统,并且依据线性二次型调节器(LQR)最优控制理论推导出TCIPC的非线性控制规律。搭建了带调谐型TCIPC的单机无穷大系统简化模型进行仿真。仿真结果验证了采用逆系统方法设计的控制策略可以在系统发生大干扰后具有良好的控制性能,能够达到提高电力系统暂态稳定性的作用。     

阻尼线性最优励磁控制器的设计与仿真分析

为了进一步改善传统线性最优励磁控制中的动态性能和调节精度,保证电力系统运行的稳定性,本文设计了一种新的阻尼线性最优励磁控制器(DLOEC)。传统的线性最优励磁控制器(LOEC)状态方程使用Q矩阵表示,而DLOEC基于无阻尼机械振荡频率的不变性,为控制系统提供了给定的衰减系数,从而提高了控制器的动态性能。经过Matlab仿真,结果表明:与常规的电力系统稳定性控制能力相比,本文设计的DLOEC能够有效提高电力系统稳定性,同时具有良好的动态响应速度和阻尼特性。     

复杂系统非线性励磁控制的数字仿真研究

对一个IEEE典型的13机系统进行了数字仿真。比较了在其中一台发电机上装设比例积分微分控制器(PID)、电力系统镇定器(PSS)、线性最优励磁控制器(LOEC)和非线性励磁控制器(NEC)四种励磁控制器，对整个系统的暂态稳定的影响。仿真结果表明，非线性励磁控制器与采用其他三种控制器相比，电力系统的暂态稳定性有较明显的改善。在多机系统中的主力发电机组上装设非线性励磁控制器，将对整个系统的大干扰稳定性有明显的改善，从而揭示了非线性励磁控制(NEC)较其它3种励磁控制方式具有更优越的性能。     

广域阻尼控制器和STATCOM控制器协调设计

为了改善互联电力系统阻尼,研究了广域阻尼控制器和静止同步补偿器(STATCOM)的控制器参数全局优化方法.首先介绍了广域阻尼控制器和STATCOM及其控制器数学模型,然后描述了改进的细菌觅食优化(BFO)算法.用Matlab编程,按BFO方法优化控制器参数以使ITSE型适应度值最小.适应度值是通过解电力系统微分-代数方程求得.10机39母线新英格兰系统被用于测试协调设计方法.仿真测试表明,广域阻尼控制器和STATCOM控制器的协调设计能增强电力系统动态稳定性.     

Memory-based dynamic event-triggered control for networked interval type-2 fuzzy systems subject to DoS attacks

In this article, the memory-based dynamic event-triggered controller design issue is investigated for networked interval type-2 (IT2) fuzzy systems under non-periodic denial-of-service (DoS) attacks. For saving limited network bandwidth, a novel memory-based dynamic event-triggered mechanism (DETM) is proposed to schedule data communication. Unlike existing event-triggered generators, the developed memory-based DETM can utilize a series of newly released signals and further save network resources by introducing interval dynamic variables. Moreover, to improve design flexibility, an IT2 fuzzy controller with freely selectable fuzzy rule number and premise membership functions (MFs) is synthesized. Then, a new switched time-delay system with imperfectly matched MFs is established under the consideration of memory-based DETM and DoS attacks simultaneously. Besides, based on the property of MFs, the boundary information of membership grades and slack matrices are introduced in the stability analysis. Furthermore, by using a piecewise Lyapunov–Krasovskii method, membership-functions-dependent criteria are deduced to ensure the asymptotic stability of built fuzzy switched systems. Finally, the effectiveness of proposed control strategies is demonstrated by simulation examples.     

孤岛微电网的分布式有限时间事件触发二次协调控制

针对传统的下垂控制策略会导致孤岛微电网稳态角频率和电压偏离额定值,且其依赖周期性通信的问题,提出一种孤岛微电网的分布式有限时间事件触发二次协调控制.首先基于多智能体系统的追踪一致性,即以系统稳态电压和角频率参考值为虚拟领航者,视分布式电源(DG)为多智能体系统的智能体,来实现系统电压和角频率的恢复控制以及期望的有功功率比例分配.然后设计了分布式有限时间事件触发二次协调控制,且只在事件触发时刻进行信息交换,其余时刻利用状态估计器输出代替DG实际状态.采用李雅普诺夫方法分析了所提策略的稳定性和可行性.最后在MATLAB/Simulink中搭建孤岛微电网测试系统进行仿真分析,仿真结果及理论分析验证了所提控制方法的有效性和优越性.     

Compound conditions event-triggered tracking control for nonlinear multiagent systems with nonlinear output faults

This article is devoted to investigating the compound conditions event-triggered prescribed performance tracking problem for strict-feedback nonlinear multiagent systems with nonlinear output faults and unknown disturbances. A simplified event-triggered sampling condition is designed to successfully reduce the number of state triggered design parameters. Besides, a compound conditions event-triggered mechanism is constructed, which integrates state triggered and controller triggered simultaneously to reduce communication burden. Furthermore, by using disturbance observers and prescribed performance functions, unknown external disturbances are compensated and the tracking errors can converge into the prescribed boundary, respectively. Moreover, all the signals of the closed-loop system are semiglobally uniformly ultimately bounded. Finally, the availability of the proposed control strategy is testified via simulation results.     

Adaptive H∞ event-triggered load frequency control in islanded microgirds with limited spinning reserve constraints

Using an islanded microgrid (MG) with large-scale integration of renewable energy is the most popular way of solving the reliable power supply problem for remote areas and critical electrical users. However, compared with traditional power systems, the limited spinning reserves and network communication bandwidth may cause weak frequency stability in the presence of stochastic renewable active outputs and load demand fuctuations. In this paper, an adaptive event-triggered control (ETC) strategy for a load frequency control (LFC) system in an islanded MG is proposed. First, a bounded adaptive event-triggered communication scheme is designed. This not only saves on network resources, but also ensures that the control center has a sensitive monitoring ability for the MG operating status when the frequency deviations have been efectively damped. Secondly, by fully considering the spinning reserve constraints and uncertain communication delays, the LFC system is described as a nonlinear model with saturation terms. Design criteria for ETC parameters are strictly deduced based on Lyapunov stability theory. Finally, an ETC parameter optimization algorithm based on random direction search is developed to reconcile the bandwidth occupancy and control performance. The efectiveness of the proposed method is verifed in an MG test system.     

Event-triggered mean square consensus of linear multiagent systems with measurement noises

This article investigates mean square consensus of linear multiagent systems with measurement noises based on event-triggered control. Considering various uncertain factors in the communication environment, multiplicative noises exists in the information that each agent measures from its neighbors. In order to save limited resources and to exclude the Zeno phenomenon, the update of the controller for each agent is driven by properly defined event-triggered condition. Sufficient conditions are given to ensure exponential mean square consensus of multiagent systems with multiplicative noises by utilizing static and dynamic event-triggered scheme. The interevent times of static event-triggered mechanism is less than those of corresponding dynamic case for each agent. Finally, validity of the theoretical results is illustrated through a simulation example.     

智能电网环境下分布式阻尼控制器设计

智能电网以广域测量系统作为支撑,通过信息的相互关联来有效控制电网稳定运行。在智能电网环境下,针对广域互联电力系统的低频振荡问题,利用分布式网络控制的灵活特性,研究设计一种计及时延的分布式阻尼控制器。考虑将测量信息作为阻尼控制器的输入信号,只涉及到本地及相邻通信节点的信息,进而基于图论新颖法对分布式阻尼控制器输入信号的通信拓扑特性进行描述。在设计广域系统中控制器时考虑到了远程信号的传输时延,并利用其时延依赖稳定性这一充分条件。最后运用到四机两区系统的仿真对比结果,显示本文提及的分布式阻尼控制器不仅使系统阻尼得到有效提高,还体现出局部与区域间低频振荡以及传输线功率振荡的可抑制性,增强了融合电力信息系统的稳定性。     

孤岛交直流混合微电网群多级功率管理策略

为实现孤岛交直流混合微电网群的稳定优化运行,提出一种多级功率管理策略。该策略包含两部分:多级功率分配控制策略和多级功率互动管理策略。多级功率分配控制策略通过功率自治级、功率互助级和功率平衡级等三级控制,实现系统功率的分散管理。考虑系统互联通信正常和通信故障2种运行情况,提出一种适用于交直流混合微电网群的多级功率互动管理策略,实现各功率分配级之间合理的切换管理,保证孤岛系统的供电质量,并减少系统功率互动损耗。设计事件触发控制器,实现多级功率互动管理策略仅在事件触发时刻进行数据交换,降低系统对通信网络的要求。最后,通过MATLAB/Simulink仿真平台验证了所提控制策略的有效性。     

Reinforcement learning-based optimized output feedback control of nonlinear strict-feedback systems with event sampled states

This article focuses on the event-triggered optimized output feedback control problem for nonlinear strict-feedback systems. First, a fuzzy state observer is designed to estimate the unmeasurable states. Then, the fuzzy-based reinforcement learning is performed under critic-actor architecture to realize the optimized control. In addition, a novel event-triggered mechanism is developed for the system states to greatly economize communication resources. By means of the Lyapunov stability theory, it can be proved that all signals of the closed-loop system are bounded, and the Zeno behavior can be successfully avoided. Lastly, an inverted pendulum example is provided to confirm the effectiveness of the derived algorithm.