基于观测器的汽轮发电机气门开度的时滞无关控制

本文考虑了具有非线性关联作用的带中间再热器的汽轮发电机的数学模型, 研究了气门开度基于观测状态的时滞无关分散控制器的设计问题. 首先把非线性关联函数变换为子系统状态变量的二次有界不等式, 然后通过构造适当的Lyapunov泛函, 并利用线性矩阵不等式(LMI)的处理方法, 得到了使汽轮发电机组渐近稳定的LMI充分条件. 此外,还提出了了控制器增益矩阵和观测器增益矩阵的求解算法.. 最后以两机无穷大母线系统为例进行了仿真分析, 验证了该方法的有效性.     

一类切换模糊时滞组合系统的分散镇定

提出了切换模糊时滞组合系统模型,并研究了状态和互联项具有时滞情况下的分散镇定问题.当每个互联子系统中的每个切换子系统具有有限个备选的状态反馈控制器,且单一控制器均不能保证系统稳定的情况下,利用多Lyapunov函数方法给出了时滞相关的矩阵不等式条件和分散切换律设计方法,使系统在所提出的分散切换律和分散控制器下渐近稳定.仿真结果表明了所提出方法的有效性.     

基于Hamilton函数方法的多机多负荷电力系统分散励磁控制

采用Hamilton函数方法研究了多机多负荷电力系统的励磁控制问题. 首先, 通过预置状态反馈完成了系统的耗散Hamilton实现. 然后, 基于该耗散实现形式设计了非线性分散励磁控制器, 分析了闭环系统的稳定性. 该控制器能充分利用系统内在的功率平衡特性. 仿真结果验证了控制策略的有效性.     

一类不确定广义系统的分散容错控制

讨论一类不确定广义系统分散容错控制器设计问题.首先利用线性矩阵不等式(LMI)设计分散状态反馈控制器,使得广义系统执行器未出现故障时渐近稳定;接着针对广义系统的部分执行器出现故障的情况设计分散状态反馈控制器,使得闭环广义系统渐近稳定;进而利用LMI设计广义系统在分散状态反馈作用下具有完整性的容错控制器;同时对传感器故障情形设计了广义系统在分散输出反馈作用下具有完整性的容错控制器,得到了不确定广义系统关于执行器和传感器的分散容错控制器设计的方法.将所设计的控制器用于实际电子网络系统,验证了所提出方法的有效性.     

不确定性关联奇异大系统时滞相关分散鲁棒镇定

针对一类不确定关联时滞奇异大系统,利用Lyapunov稳定性理论与时滞积分矩阵不等式相结合的方法,研究其时滞相关分散鲁棒镇定问题,目的是设计一无记忆状态反馈分散控制器,使闭环系统鲁棒稳定.用矩阵不等式方法,给出了该类系统时滞相关分散鲁棒镇定的充分条件.所得结果与系统时滞的大小有关,并以矩阵不等式的形式给出.最后用数值算例说明了所给方法的可行性和有效性.     

一类离散的不确定切换模糊组合系统的分散H∞控制

针对一类离散的不确定切换模糊组合系统,利用平行分布补偿算法(PDC)给出分散切换模糊控制器的设计方法,利用多Lyapunov函数方法,给出使系统稳定且H∞控制问题可解的矩阵不等式条件,并给出分散切换律设计.仿真结果表明方法的有效性.     

改进的网型结构电力系统鲁棒重叠分散控制

研究一类多区域互联电力系统的特殊重叠分解及其鲁棒分散控制问题,提出一种新的互联电力系统重叠分解的方法。该方法根据电力系统本身的结构信息约束和大系统包含原理的约束条件,对系统进行重叠分解处理,使原系统扩展成为两两子系统;然后,在有机结构控制(OSC)的线性矩阵不等式(LMI)方法的基础上,为系统设计了改进的鲁棒分散控制器。以一个4区域网型结构电力系统为例进行仿真研究,其结果表明,所设计的控制器较直接使用LMI方法能使系统具有更令人满意的控制性能。     

一类不确定切换模糊组合系统的分散鲁棒镇定

提出一种切换模糊组合系统模型并讨论其鲁棒控制问题.分别利用单Lyapunov函数方法和多Lyapunov函数方法设计出分散切换律和控制器,给出了系统在分散切换律和分散控制器作用下的矩阵不等式可镇定条件.仿真结果表明了该设计方法的有效性.     

参数不确定T-S模糊交联系统的分散保成本控制

研究了参数不确定T-S模糊交联系统的分散保成本控制问题.对于给定系统所容许的所有不确定参数,设计了分散状态反馈保成本控制器,使得闭环系统不仅渐近稳定而且具有适当的性能指标上界.基于线性矩阵不等式(LM I)处理方法,给出了分散控制器存在的充分条件.仿真算例表明了所给方法的简易、有效.     

一类切换线性奇异系统的状态反馈H∞控制*

研究了一类由任意多个子系统组成的线性切换奇异系统的状态反馈H∞控制问题。采用共同Lyapunov函数方法和凸组合技术,给出由矩阵不等式表示的使闭环系统渐近稳定且满足H∞性能的控制器存在的充分条件, 并设计了相应的子控制器和切换策略。采用矩阵变换,将矩阵不等式等价转换为一组线性矩阵不等式。数值算例说明了所提方法的有效性和可行性。     

Non-linear decentralized saturated controller design for multi-machine power systems

A direct method of constructing a decentralized saturated controller is very important in the controller design of multimachine power systems. Among the existing designs the author first constructed a state feedback, then saturated the controller. However, the author could not prove that this saturated controller was valid. In this paper a multi-machine power system as a Hamiltonian control system with dissipation is first represented. Then using a Hamiltonian function a decentralized saturated excitation control scheme, which is a static measurable feedback, is proposed. Last, the design is discussed in detail on a three-machine power system. Simulations show that the saturated, simple control law works well.     

Sequential decentralized control with a prescribed degree of stability

In this paper, a new approach to decentralized stabilization and control is proposed. This approach combines a suboptimal high-gain output-feedback controller design with a sequential high-gain decentralized control scheme such that at each stage of the sequential scheme, the retained optimal closed loop eigenstructure has a prescribed degree of stability. This new algorithm is illustrated on a practical problem, the decentralized stabilization and control of a multi-machine power system.     

Differential evolutionary algorithm for TCSC-based controller design

In this paper, a systematic procedure for modelling, simulation and optimal tuning the parameters of a thyristor controlled series compensator (TCSC) controller, for the power system stability enhancement is presented. The design problem of the proposed controller is formulated as an optimization problem and differential evolution (DE) is employed to search for optimal controller parameters. A detailed analysis on the selection of objective function and controller structure on the effectiveness of the TCSC controller is carried out and simulation results are presented. The dynamic performance TCSC controller under various loading and disturbance conditions are analyzed and compared. Finally, the proposed design approach is extended to a multi-machine power system for simultaneous design of multiple and multi-type controllers.     

On decentralized controllers for interconnected power systems

In this paper a scheme for a decentralized controller based on the modelling of interaction in large interconnected power systems is proposed. An example of a two-area power system is presented to illustrate the application of the proposed design procedure in both the continuous-time and discrete-time case. The computer simulation results revealed that the performance of the proposed decentralized controller is comparable to that of a centralized controller.     

A brand new nonlinear robust control design of SSSC for transient stability and damping improvement of multi-machine power systems via pseudo-generalized Hamiltonian theory

Nonlinear robust control of static synchronous series compensator (SSSC) is investigated in multi-machine multi-load power systems by using the pseudo-generalized Hamiltonian method. First, the uncertain nonlinear differential algebraic equation model is constructed for the power system. Then, the dissipative pseudo-generalized Hamiltonian realization of the system is established by means of variable transformation and prefeedback control. Finally, based on the obtained dissipative pseudo-generalized Hamiltonian realization, a brand new nonlinear robust controller is put forward. The proposed controller can effectively use the internal structure and the energy balance property of the power system. Simulation results demonstrate the effectiveness and robustness of the control scheme.     

The optimal decentralized control of a large power system: Load and frequency control

The load and frequency control of a multi-area interconnected power system is studied. In this problem, the system is assumed to be subject to unknown constant disturbances, and it is desired to obtain, if possible, robust decentralized controllers so that the frequency and tieline/net-area power flow of the power system are regulated. The problem is solved by using some structural results recently obtained in decentralized control, in conjunction with a parameter optimization method which minimizes the dominant eigenvalue of the closed-loop system. A class of minimum order robust decentralized controllers which solves this general multi-area load and frequency control problem is obtained. Application of these results is then made to solve the load and frequency control problem for a power system consisting of nine synchronous machines (described by a 119th-order system). It is shown that the load and frequency controller obtained in this case is not likely to be significantly improved by using more complex controllers; in particular, it is shown that the conventional controller, used in regulating the net-area power flow of a system, is not likely to be significantly improved upon by using more complex controllers.     

Design of decentralized robust load-frequency controller based on SVD method

A decentralized robust control scheme is presented for the load-frequency control of interconnected power systems with uncertain parameters. A singular value decomposition (SVD) technique and Lyapunov stability theory are adopted to implement a decentralized robust controller. The stability analysis of the closed-loop interconnected systems for all admissible uncertainties is discussed. The performance robustness of the proposed decentralized robust control scheme has been verified through simulation studies on a two-area power system model. The effectiveness of the decentralized control algorithm is compared to that of a centralized robust one. It has been found that both control schemes have almost the same performance with integral control action in the presence of parametric uncertainty in the plant.     

Design of dual-dimensional controller based on multi-objective gravitational search optimization algorithm for amelioration of impact of oscillation in power generated by large-scale wind farms

This paper studies the impact of high penetration of wind generation technology on dynamic stability of power networks. A mathematical model of a multi-machine power system, including Large-scale Wind Power Generation System (LWPGS) incorporating active power oscillation due to tower shadow and wind shear phenomena is developed. Based on this model, an extended Small-Signal Scrutiny (SSS) procedure to study the impact of oscillatory modes on mechanical vibrations is proposed. The critical operating points that can be dangerous for power system performance are detected. The study is based on modified 16-machine 5-area network with lightly damped electromechanical modes. A dual-dimensional controller for LWPGS is proposed. The first and second dimensions of the designed controller are based on wide-area and local signals, respectively. Selection of the best input of the LWPGS is based on Singular Value Decomposition (SVD) analysis, while the qualified remote control signal is found by geometric approach. Multi-Purpose Gravitational Search Algorithm (MPGSA) based on fuzzy decision making is applied for the coordinated design of LWPGS controller and accelerating power PNS (PNS2B) of the synchronous machines. The simulation results are presented to elucidate the effectiveness of the well-tuned damping controller of the LWPGS.     

Transient stability improvement of multi-machine power systems using on-line fuzzy control of SMES

Fuzzy control of the super-conducting magnetic energy storage (SMES) is proposed here to improve the transient stability and damping requirements of multi-machine power systems. The effects of the SMES control on the line power transfer are considered in the design of the fuzzy controller. A theoretical realisation of the proposed control scheme is presented and a simulation study on the New-England test system is carried out. A practical implementation, based on local measurements, is explained. The improvement of the system’s critical clearing time, and also the system damping requirements, are clearly demonstrated. Finally, a conclusion is provided.