静止移相器的非线性L2增益干扰抑制控制

静止移相器既可以用于优化潮流,也可以提高系统的暂态稳定性。文中首先构造了含静止移相器的电力系统鲁棒模型,然后在耗散系统理论下,利用递推方法构造存储函数,从而推导出了一种非线性的L2增益意义下的干扰抑制控制器。这种控制器很好地反映了系统的非线性特征,并使系统对干扰到输出的L2增益有限。仿真结果表明在该控制器作用下,闭环系统能很好地抑制干扰,特别在大干扰条件下能很快恢复稳定。     

永磁直线伺服电机L2鲁棒控制的研究

对永磁直线电机伺服系统提出非线性L2鲁棒控制.给出电机的非线性数学模型,在此基础上,为实现对速度和电流的准确跟踪,建立了误差系统的动态模型;将跟踪和干扰抑制归结为L2设计问题,通过构造适当的存储函数得到描述系统L2控制器的两个定理;证明定理给出的控制器能满足干扰抑制和系统的渐进稳定.仿真结果表明,用该方法设计的系统能很好的抑制扰动和跟踪给定,满足对高性能永磁直线伺服系统控制的要求.     

ASVG的非线性L2增益干扰抑制控制器

将非线性鲁棒控制方法用于先进的静止无功发生器（ASVG）的控制。基于电力系统动态、耗散系统理论框架和非线性L2增益干扰抑制方法,建立了单机无穷大系统中的ASVG鲁棒控制数学模型。模型中考虑了来自发电机转子轴上的机械功率扰动和ASVG输出电压的扰动。并在此基础上,采取递推设计方法构造能量存储函数,以避免求解HamiltonJacobiIssacs不等式,从而得到ASVG的非线性L2增益干扰抑制控制规律。单机无穷大系统的仿真结果证明,与传统PID PSS控制方式相比,在此控制规律下,ASVG能够更有效地阻尼系统振荡,提高系统暂态稳定性能。     

包含静止无功补偿器的电力系统非线性控制研究

研究包含静止无功补偿器的电力系统非线性控制的一种新方法.文中首先给出包含静止无功补偿器的电力系统非线性数学模型,再利用广义哈密顿(Hamilton)系统理论,对其进行哈密顿实现,并提出了一种L2增益意义下的干扰抑制方法,得到了实现干扰抑制的控制规律.详细阐述了该方法的理论依据和控制律的具体设计过程.单机无穷大系统情况下的仿真结果表明,该方法所设计的控制规律能有效抑制干扰的影响,提高电力系统暂态稳定性.     

基于自适应Backstepping的SVC鲁棒L2性能控制设计

针对含有静止无功补偿器（SVC）的单机系统中的各种不确定性因素,讨论了SVC的自适应鲁棒控制问题。将L2增益设计方法与Backstepping方法相结合,同时引入参数估计思想,通过递归地构造整个系统的能量存储函数获得闭环反馈控制律,保证系统对干扰输入具有L2性能,对未知参数具有自适应性。仿真结果表明,所设计控制器在系统受扰时可以使系统较快稳定,暂态过程中有效维持SVC接入点电压,系统对外部干扰具有较强的鲁棒性。     

非线性汽门控制器的自适应鲁棒逆推设计

针对带有内部及外部扰动的汽轮机调速系统，使用自适应逆推方法构造出调速系统的存贮函数，进而同时获得非线性L2增益干扰抑制控制器及参数替换律。该控制器在内部扰动中重点考虑了输电线路参数的不确定性，因此不仅能够抑制干扰对系统输出的影响，而且对系统参数变化也具有很强的鲁棒性。同时，基于该方法的设计过程系统、简明，易为工程人员所接受。仿真结果表明该自适应逆推方法设计的控制器拥有优越的性能。     

永磁直线伺服系统非线性自适应鲁棒控制器设计

对永磁直线伺服系统提出非线性自适应鲁棒控制器的设计方法。在永磁直线伺服系统非线性数学模型的基础上,为实现对速度和电流的准确跟踪,建立了误差系统的动态模型。将跟踪和干扰抑制归结为非线性自适应鲁棒控制器设计问题,通过构造存储函数得到包含电阻辨识算法的自适应鲁棒控制器的定理,证明定理给出的控制器能满足干扰抑制和系统的渐进稳定。仿真结果表明,用该方法设计的系统能很好的抑制扰动和跟踪给定,满足对高性能永磁直线伺服系统控制的要求。     

无轴承永磁同步电动机的非线性L2鲁棒控制

对无轴承永磁同步电动机提出非线性L2鲁棒控制。在考虑负载、电机电阻以及转子离心力等各种干扰的情况下建立了电机的非线性数学模型,并且通过构造适当的存储函数推导出用于描述L2鲁棒控制器的四个控制律,最后利用仿真测试转速和转子悬浮的抗干扰性能证实了控制律能满足干扰抑制和系统的渐进稳定。     

基于L2增益的永磁同步电动机无速度传感器的自抗扰控制

针对面装式永磁同步电机转速调节问题,提出了一种新颖的调速系统.利用L2增益干扰抑制理论设计了鲁棒速度控制器,使得控制器能够满足干扰抑制和子系统的渐进稳定;利用自抗扰控制技术设计了q轴电流控制器,具有对电流较强的适应性、鲁棒性和可操作性.针对速度估计问题,利用一种模型参考自适应方法估计转速和位置,节约了成本和增强了系统的可靠性.仿真结果表明,该方法设计的系统能很好地抑制扰动和跟踪给定,具有良好的动、静态性能.     

基于哈密顿系统理论的超导储能装置控制器的设计

针对电力系统非线性的特点，将电力系统中的一类仿射非线性系统转换为标准的哈密顿系统，进行了超导储能SMES（Superconducting Magnetic Energy Storage)有功功率的控制设计，对无功功率用传统的比例环节进行设计，基于受控哈密顿系统理论，建立了SMES装置的端口受控哈密顿PCH（Port Controlled Hamiltonian)模型，针对系统的外界干扰和参数不确定性，采用自适应KL2增益控制设计方法设计了含有SMES装置的单机无穷大电力系统的自适用L2增益控制器。仿真结果表明，采用基于哈密顿系统理论的自适应L2增益控制方法对SMES有功功率的设计，利用传统的比例积分PI（Proportion Integration)控制器进行无功功率控制，能够有效地抑制干扰，显著地改善系统的动态性能。     

Nonlinear decentralized disturbance attenuation excitation controlvia new recursive design for multi-machine power systems

In this paper, a new nonlinear decentralized disturbance attenuation excitation control for multi-machine power systems is proposed based on recursive design without linearization treatment. The proposed controller improves system robustness to dynamic uncertainties and also attenuates bounded exogenous disturbances on the system in the sense of L₂-gain. Computer test results on a 6-machine system show clearly that the proposed excitation control strategy can enhance transient stability of power systems more effectively than other excitation controllers     

Coordinated Design of Power System Stabilizers and Static Phase Shifters Using Genetic Algorithm

Coordinated design of a power system stabilizer (PSS) and a static phase shifter (SPS) using genetic algorithm (GA) is investigated in this paper. The design problem of PSS and SPS controller is formulated as an optimization problem. An eigenvalue-based objective function to increase the system damping is proposed. Then, GA is employed to search for optimal controller parameters. Different control schemes have been proposed and tested on a weakly connected power system with different disturbances, loading conditions, and parameter variations. It was observed that although the PSS enhances the power system stability, the SPS controller provides most of the damping and improves the voltage profile of the system. The nonlinear simulation results show the effectiveness and robustness of the proposed control schemes over a wide range of loading conditions and system parameter variations.     

Superconducting energy storage technology-based synthetic inertia system control to enhance frequency dynamic performance in microgrids with high renewable penetration

With high penetration of renewable energy sources (RESs) in modern power systems, system frequency becomes more prone to fluctuation as RESs do not naturally have inertial properties. A conventional energy storage system (ESS) based on a battery has been used to tackle the shortage in system inertia but has low and short-term power support during the disturbance. To address the issues, this paper proposes a new synthetic inertia control (SIC) design with a superconducting magnetic energy storage (SMES) system to mimic the necessary inertia power and damping properties in a short time and thereby regulate the microgrid (µG) frequency during disturbances. In addition, system frequency deviation is reduced by employing the proportional-integral (PI) controller with the proposed SIC system. The efficacy of the proposed SIC system is validated by comparison with the conventional ESS and SMES systems without using the PI controller, under various load/renewable perturbations, nonlinearities, and uncertainties. The simulation results highlight that the proposed system with SMES can efficiently manage several disturbances and high system uncertainty compared to the conventional ESS and SMES systems, without using the PI controller.     

Mismatched disturbance attenuation control for static var compensator with uncertain parameters

The use of a static var compensator (SVC) as a component of flexible alternating current transmission system (FACTS) devices to control power systems has been investigated for decades. Its aim is to regulate the system voltage and improve the stability and loadability of power systems. A typical assumption in such a system is that the parameters of the controlled system are known accurately, which is rarely satisfied in practice. This paper explores the development of a simple but effective controller for a single-machine infinite-bus power system with SVC subjected to both matched and mismatched disturbances where the controller derivation is based on the assumption that all parameters used in the system modeling are unknown, but bounded in size. The research in this paper illustrates how an indirect robust control can be incorporated with a modified disturbance observer-based feedforward term to attenuate the influence of parameter variations and disturbances from the outputs of the system. Simulation results are presented to confirm the effectiveness of the proposed scheme.     

Load-frequency control with disturbance accommodation

The problem of load-frequency control is investigated using disturbance-accommodation control. It is shown that the optimal accommodation of load disturbances can lead to significantly better performance than that of conventional controllers. It is further shown that the complete cancellation of all disturbance effects in the class of power systems considered is impossible. Nevertheless, the disturbance effects in system frequency can be cancelled completely. Simulation results are presented for the case of an ideal one-area system and the data clearly demonstrates the degree of performance improvement made possible by a DAC controller.     

Robust nonlinear adaptive backstepping excitation controller design for rejecting external disturbances in multimachine power systems

This paper proposes a new approach to design a robust adaptive backstepping excitation controller for multimachine power systems in order to reject external disturbances. The parameters which significantly affect the stability of power systems (also called stability sensitive parameters) are considered as unknown and the external disturbances are incorporated into the power system model. The proposed excitation controller is designed in such a way that it is adaptive to the unknown parameters and robust to external disturbances. The stability sensitive parameters are estimated through the adaptation laws and the convergences of these adaptation laws are obtained through the negative semi-definiteness of control Lyapunov functions (CLFs). The proposed controller not only provides robustness property against external disturbances but also overcomes the over-parameterization problem of stability sensitive parameters which usually appears in some conventional adaptive methods. Finally, the performance of the proposed controller is tested on a two-area four machine 11-bus power system by considering external disturbances under different scenarios and is compared to that of an existing nonlinear adaptive backstepping controller. Simulation results illustrate the robustness of the proposed controller over an existing one in terms of rejecting external disturbances.     

Design and Implementation of a Class of Robust H ∞ Control for Stability Enhancement in Power Systems

The paper presents a method of designing a class of robust H X generator excitation controller in a power system. The proposed controller is utilized to damp inter-area oscillations and enhance power system stability. The robust controller design procedure for a linear composite system is presented in terms of positive definite solutions to modified algebraic inequalities. The resulting controller guarantees closed-loop stability and an H X -norm bound on disturbance attenuation. The effectiveness of the H X controller is demonstrated through digital simulation studies on a two-machine system. The digital simulation studies are conducted using a PSCAD/EMTDC software package. The simulation results show that the controller contributes significantly to the damping of inter-area oscillations and the enhancement of power system stability during disturbances.     

SHAPF的双闭环线性自抗扰控制

鉴于并联混合型有源电力滤波器(SHAPF)的动态性能要求,针对一种适用于现有中高压配电系统的三相SHAPF,在其状态空间模型的基础上,设计出一种基于线性自抗扰控制(LADRC)技术的双闭环控制系统。基于LADRC的控制系统能够估计出系统所有不确定因素和外部干扰等引起的总扰动并进行补偿,补偿性能良好,其算法简单,易于实现,具有一定的工程应用价值。仿真结果验证了基于LADRC的控制策略的有效性。     

A Lyapunov theory based UPFC controller for power flow control

Unified power flow controller (UPFC) is the most comprehensive multivariable device among the FACTS controllers. Capability of power flow control is the most important responsibility of UPFC. According to high importance of power flow control in transmission lines, the proper controller should be robust against uncertainty and disturbance and also have suitable settling time. For this purpose, a new controller is designed based on the Lyapunov theory and its stability is also evaluated. The Main goal of this paper is to design a controller which enables a power system to track reference signals precisely and to be robust in the presence of uncertainty of system parameters and disturbances. The performance of the proposed controller is simulated on a two bus test system and compared with a conventional PI controller. The simulation results show the power and accuracy of the proposed controller.     

Adaptive estimation and rejection of unknown sinusoidal disturbances through measurement feedback for a class of non‐minimum phase non‐linear MIMO systems

This paper develops an adaptive estimation method to estimate unknown disturbances in a class of non‐minimum phase non‐linear MIMO systems. The unknown disturbances are generated by an unknown linear exosystem. The frequencies, phases and amplitudes of the disturbances are unknown, the only available information of the disturbances is the number of distinctive frequencies. The system considered in this paper is a class of MIMO non‐linear systems in the output feedback form which can be non‐minimum phase. The proposed estimation algorithm provides exponentially convergent estimates of system states, unknown disturbances in the system and frequencies of the disturbances characterized by the eigenvalues of the exosystem. Moreover, based on the stabilization controller for the disturbance free system, the estimates of the disturbances are used to solve the disturbance rejection problem. The unknown disturbances are compensated completely with the stability of the whole closed‐loop system. Copyright © 2006 John Wiley & Sons, Ltd.