A robust adaptive control with unmodeled dynamic for HVDC transmission systems

Utilizing the feature of quick response of HVDC to improve the performance of AC/DC system has become the emphasis to be researched. This paper introduces firstly the principle of the robust adaptive control of nonlinear systems with unmodeled dynamics, then developed the robust adaptive additional control of HVDC with unmodeled dynamics of generator in order to improve stability of power system. The additional control of HVDC with unmodeled dynamics only uses the local signals and its design is simple, furthermore it can obviously improve the stability of power system in different operational conditions. Experimental results using the presented concepts obtained on single machine infinite bus model are also included. These results prove the efficiency of the control scheme. The design process of controller provided a new idea to design controller by use of simplified model. __________ Translated from Journal of Sichuan University (Engineering Science Edition), 2005, 37(5): 154–158 (in Chinese)     

Stability analysis of a combined direct variable structure adaptive control – the discrete‐time case

This paper presents the proofs of robust stability of a discrete‐time robust model reference controller combined with variable structure in an adaptive framework. All the proofs of robust stability are derived for the discrete‐time case and are similar to those already existing for the conventional non‐combined case. The controller is applied to a SISO LTI plant with unmodeled dynamics of multiplicative and additive types. It is shown that the combined controller can arbitrarily improve the convergence of the error while maintaining the robustness if compared with the non–combined case. Simulation results illustrate the performance of the proposed control strategy. Copyright © 2016 John Wiley & Sons, Ltd.     

电力市场环境下风电-光热-生物质混合电站鲁棒优化调度模型

以风电场、光热电站、生物质锅炉等组成混合电站并参与到电力市场中,能有效提高整体的运营收益.为解决混合电站参与电力市场运行问题,从混合电站的结构及运行机理出发,提出了电力市场下风电-光热-生物质混合电站鲁棒优化调度模型.该模型以最大化运行利润为目标函数,考虑了混合电站参与电力市场所获收益、并网运行环境效益、弃风弃光惩罚成...     

槽式太阳能集热场温度控制研究

为了将槽式太阳能集热回路的导热工质出口温度控制在合理范围内,需要研究调节迅速、控制效果良好的集热场出口温度控制系统。以1 MW槽式太阳能热发电实验系统为研究对象,建立了槽式集热回路动态数学模型,并基于模型开发了集热场导热工质出口温度内模控制器,并基于Simulink仿真平台搭建了集热回路工质出口温度PID控制系统和内模控制系统,对比分析了多扰动情况下2种系统的控制效果。结果表明：在太阳辐照、导热工质入口温度和环境温度的共同作用下,相较于PID控制系统,内模控制系统调节时间更短,超调量更小,控制效果更优。     

基于扰动观测器的光伏逆变器鲁棒分数阶PID控制

文中设计了一款基于扰动观测器的鲁棒分数阶PID控制(Perturbation Observer based Robust Fractional-order PID control,PORF-PID)来实现光伏逆变器的最大功率跟踪。将光伏逆变器的非线性、参数不确定性以及未建模动态聚合成一个扰动,并通过滑模扰动观测器(Sliding-Mode Perturbation Observer,SMPO)对其进行在线估计。随后,采用分数阶PID控制(Fractional-order PID control,FPID)对该扰动估计进行实时完全补偿,从而实现不同工况下全局一致的控制性能。由于引入了分数阶控制框架,额外的控制器参数可进一步提高闭环系统的动态响应特性。为验证所提控制器的有效性,文中进行了两种算例研究,即光照强度变化和电网电压跌落。仿真结果表明,PORFPID控制与常规PID控制、FPID控制和反馈线性化控制(Feedback Linearization Control,FLC)相比,能在各类工况下实现最快的动态响应以及最低的超调量。     

基于控制系统四元组形式的发电机非线性分散鲁棒控制

分析了仅包含状态变量、输出变量、控制变量的控制系统常规三元组形式应用到发电机分散鲁棒控制时遇到的困难，为克服这些困难提出了包含状态变量、输出变量、控制变量、量测变量的控制系统四元组形式的概念。量测变量的引入使得发电机综合控制模型本身变为各机解耦、与外部系统网络参数及动态无关，在此模型下设计出分散鲁棒控制器是自然的。此模型可以考虑系统包含各种动态元件如FACTS元件、HVDC系统等情况，在此四元组模型下，通过直接寻求控制量与控制目标之间关系的关联度方法将发电机控制的四元组模型完全线性化，通过励磁控制使发电机端电压具有良好的动态特性，通过汽门控制提高发电机功角暂态稳定性。数字仿真表明，所设计的基于控制系统四元组形式的发电机非线性分散鲁棒综合控制器是有效的。     

基于分布鲁棒优化的光伏电站并网极限容量研究

针对光伏电站出力的不确定性,以及描述出力的概率分布函数难以准确获取的特点,提出将分布鲁棒线性优化理论用于研究光伏电站并网后的极限容量问题,建立了基于系统运行约束条件下的光伏电站极限容量的分布鲁棒优化模型,模型中的随机变量为太阳辐射强度,结合其上下限与期望来描述光伏电站出力的不确定,并通过对偶理论将模型转化为确定性的线性规划问题,以便于求解。在某修正的Garver's 6节点系统中,对模型进行验证,结果表明：不同的并网位置、太阳辐射变化范围均明显影响了光伏电站并网后的极限容量,并且与盒式鲁棒优化方法相比,分布鲁棒优化方法能得到更优的结果,同时该模型还能给出在最优性与鲁棒性之间灵活转换的计算结果,进而验证了该模型与方法的可行性和有效性。     

Robust damping control of power oscillation incorporating parametric resonance

In this paper we consider a damping control of low‐frequency oscillations in an electric power system. On the basis of the hypothesis that an auto‐parametric resonance model can explain a power oscillation, we propose a new model for a robust damping control, by which the system maintains stability even if some auto‐parametric resonance happens. With this model, we can express a parametric variation of a principal oscillation mode and a class of uncertainties which cover neglected dynamics. Since the model has a certain structure of uncertain parameters, we design a robust controller via µ‐synthesis. The robust controller which can be obtained from the presented design strategy has the property that the control performances are more sophisticated in comparison to controllers designed with other existing methods based on the H_∞ control. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 42–49, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10069     

计及多种柔性负荷的虚拟电厂热电联合鲁棒优化调度模型

针对热/电联合运行下多种柔性负荷协调优化不足以及面临的风、光出力和柔性负荷等多种不确定性,文章提出了一种考虑柔性负荷下的虚拟电厂(virtual power plant,VPP)热电联合鲁棒优化调度方法.充分考虑可削减、可平移、可转移柔性负荷之间的协调互补性,分别以热/电负荷曲线标准差和系统综合运行成本最低为目标,建立...     

Robust speed estimation and control of an induction motor drive based on artificial neural networks

In this paper, a speed estimation and control scheme of an induction motor drive based on an indirect field‐oriented control is presented. On one hand, a rotor speed estimator based on an artificial neural network is proposed, and on the other hand, a control strategy based on the sliding‐mode controller type is proposed. The stability analysis of the presented control scheme under parameter uncertainties and load disturbances is provided using the Lyapunov stability theory. Finally, simulated results show that the presented controller with the proposed observer provides high‐performance dynamic characteristics and that this scheme is robust with respect to plant parameter variations and external load disturbances. Copyright © 2007 John Wiley & Sons, Ltd.     

基于遗传算法的超导磁储能装置H2/H∞鲁棒控制器设计

提出了应用GA（遗传算法）设计H2／H∞鲁棒控制器的一般方法，使得在满足闭环系统的H∞范数小于指定的工程要求的条件下误差信号的H2范数最小，该问题可归结为一个带约束条件的极小值优化问题，并通过一种改进的遗传算法加以解决，该设计方法能对具有任意控制器结构的控制系统进行参数优化，与传统的鲁棒控制器设计方法相比，所提出的方法不仅可以提高控制器的鲁棒性，还具有易于进行参数优化的优点，将所提出的方法应用于超导磁储能装置（SMES）PI型鲁棒控制器的设计，时域仿真结果表明所设计的控制器具有很好的鲁棒性，在不同的运用工况下均能有效阻尼电力系统的振荡，此外，控制器还具有结构简单，易于工程实现的优点。     

基于模型参考神经网络的异步电机鲁棒速度控制方法

提出一种新型的基于模型参考神经网络的异步电机驱动系统鲁棒速度控制方法。由带负载转矩观测器的两层神经网络对象辨识器(NNPI)对未知的电机动态参数进行实时的自适应辨识与估计。由双层神经网络PI控制器(NNC)对异步电机转子速度进行鲁棒控制。神经网络使用学习算法以自动调节NNPIC的参数并有效地降低系统对参数变化以及负载扰动的敏感度。仿真结果表明该方法对于参数变化和负载转矩扰动具有很强的自适应能力,能够提高异步电机的性能,并减小其对参数变化、非线性影响以及负载扰动的敏感度。     

基于H_∞回路成形理论的舰用同步发电机系统鲁棒性控制研究

介绍了鲁棒控制器设计的回路成形理论方法,设计了舰用同步发电机系统的鲁棒控制器,并按鲁棒控制理论对状态反馈控制进行了研究。仿真研究取得了较为满意的结果。     

基于小信号稳定性分析的含VSG微电网电能质量主动控制

为提高分布式电源电力电子变换装置的利用率,实现变流器的功率控制,提高电能质量,文中提出一种基于小信号稳定性分析的含虚拟同步发电机(VSG)微电网的电能质量主动控制策略,在原有双闭环控制器基础上,设计参数化控制器进行谐波抑制,实现控制性能指标的改进。首先,建立基于微电网拓扑的VSG小信号模型,并分析VSG控制过程的稳定性。其次,设计了基于鲁棒观测器的控制器,以电能质量性能指标跟踪误差最小为目标函数,利用优化方法对跟踪误差进行逐步最优求解。通过MATLAB/Simulink对所提控制策略进行仿真,结果表明:所提出的方法实现了变流器鲁棒控制和电能质量治理,性能改善作用明显。     

基于结构保留模型的静止无功补偿器鲁棒非线性控制

采用Hamilton函数方法研究了静止无功补偿器(SVC)的鲁棒非线性控制问题。首先基于系统网络结构特点,建立了包含SVC、恒功率负荷和有界外部扰动的电力系统的结构保留不确定非线性控制数学模型,然后通过坐标变换和预置状态反馈控制完成了系统的耗散Hamilton实现。最后,基于该耗散实现设计了鲁棒控制器,并分析了闭环系统的渐近稳定性。由于充分利用了系统的内在耗散结构特性,所设计的鲁棒控制器物理意义明确,易于实现。与常规PID控制器的仿真比较表明,该鲁棒控制器作用下系统的超调量小、响应速度快,能有效抑制外部干扰对系统暂态稳定性的影响,有效提高了系统的动态性能。     

Comparison of fuzzy logic and neural network in maximum power point tracker for PV systems

This paper proposes two methods of maximum power point tracking using a fuzzy logic and a neural network controllers for photovoltaic systems. The two maximum power point tracking controllers receive solar radiation and photovoltaic cell temperature as inputs, and estimated the optimum duty cycle corresponding to maximum power as output. The approach is validated on a 100 Wp PVP (two parallels SM50-H panel) connected to a 24 V dc load. The new method gives a good maximum power operation of any photovoltaic array under different conditions such as changing solar radiation and PV cell temperature. From the simulation and experimental results, the fuzzy logic controller can deliver more power than the neural network controller and can give more power than other different methods in literature.     

A heuristic‐based design of robust SMES controller taking system uncertainties into consideration

In this paper, a heuristic‐based design of robust superconducting magnetic energy storage (SMES) controller is proposed taking system uncertainties into consideration. The SMES model with active and reactive power controllers is used. In addition, the effect of SMES coil current is also included in the model. The power system and the SMES unit with the designed controller are formulated as an optimization problem. The proposed objective function considers both the damping performance index and the robust stability index. In particular, the robust SMES controller is designed to enhance the system damping performance and robustness against system uncertainties such as various load and system parameter changes. The robust stability margin is guaranteed in terms of the multiplicative stability margin (MSM). In the proposed method, the robust SMES active and reactive power controllers are designed systematically by using hybrid tabu search and evolutionary programming, so that the desired damping performance and the best obtainable MSM are acquired. Finally, the designed SMES controller is examined under different situations to evaluate and confirm the effectiveness and robustness via eigenvalue analysis and nonlinear simulations. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

交直流互联系统鲁棒自适应直流功率调制

设计了应用于交直流互联电力系统的直流功率调制的非线性鲁棒自适应控制器。该控制器基于驱动各互联区域电网的惯量中心至统一平衡点的设计思想，采用广域测量系统的全局信号，用以阻尼交直流互联系统的区域间功率振荡。采用反步法设计的自适应鲁棒控制规律使控制器对未知参数具有自适应性，对模型误差、扰动和平衡点变化具有较强的鲁棒性。仿真结果表明，与传统的线性直流功率调制控制器相比，该控制器对联络线的功率振荡具有优良的阻尼性能，可显著提高输电极限，而且能很好地适应运行点的变化。     

Full-state Variables Control of a Grid-connected Pumped Storage Power Plant Using Non-linear Controllers

Abstract—In this article, a controller based on a multi-variable sliding mode is provided for pumped storage with four goals. (1) Full-state variables of the plant, generator, and hydro turbine are developed to improve transient responses under fault conditions by compensating the fast electrical dynamics. (2) The sliding-mode controller is designed for robustness against uncertainty in both the power system parameters and its topology. (3) Two surfaces (power angle and output voltage) are proposed to coordinate both the turbine and excitation inputs of the generator in transient conditions. (4) The decentralized method is used to decrease the complexity of the controller equations and cost of implementation. To show the effectiveness of the proposed controller, two other controllers—full-state variables feedback linearization and a generic power system stabilizer—are simulated by MATLAB/Simpower (The MathWorks, Natick, Massachusetts, USA). The simulation results show full-state variables feedback linearization cannot be robust against model uncertainty; it is also shown that the power plant with linear controller has unpleasant transient responses in both fault conditions and low-frequency oscillations. In contrast, the proposed method plays an effective role in solving the mentioned problems and limits the stator current magnitude and terminal voltage post-fault.     

Modelling,simulation and optimisation of robust PV based micro grid for mitigation of reactive power and voltage instability

This paper proposes a robust H-infinity STATCOM controller for compensating reactive power in stand-alone micro grid consisting of a PV–Wind–Diesel hybrid system. In order to carry out MATLAB based simulation, a small signal linear model of the stand-alone hybrid power system is considered, comprising of a photo voltaic cell, a DFIG based wind turbine and a diesel generator. Synchronous generator based DG acts as a backup for the hybrid system. Generally these standalone systems experience frequent variation of loads, wind power input and solar radiation, which affect the vital system parameters like reactive power, terminal voltage and frequency to a great extent. These variations of system parameters with variation of load inputs are studied and its impact on overall system stability and reactive power compensation is properly monitored. Furthermore the system performance is improved and the robustness of the controller is enhanced with the incorporation of GA and PSO.