无刷双馈风力发电系统的L2鲁棒控制

针对变速恒频无刷双馈风力发电系统受风能不确定性和不稳定性影响的问题,分析风力机的运行特性及最大风能捕获的实质,将最大风能捕获问题转化为对发电机转速的控制问题,建立数学模型,利用L2范数对干扰信号加以限制.采用L2鲁棒控制方法设计控制器.L2鲁棒控制器的结构和参数都固定不变,并可以保证系统在不确定性影响最严重的情况下也能满足性能要求,使系统具有较强的抗干扰性.仿真结果表明,所设计的控制器使系统对参数不确定性及负载扰动具有较强的鲁棒性,并且能快速地跟踪风速,进而提高风能利用率.     

永磁同步电机混合LQ—H∞控制研究

为了抑制永磁同步电机存在的参数摄动、负载扰动等不确定因素对系统性能的影响,该文提出了一种将线性二次型（LQ）最优控制同H∞鲁棒控制相结合的鲁棒跟踪控制策略。H∞控制作为抗扰调节器,保证系统的鲁棒性能,克服系统中存在的模型不确定性与外部干扰对系统性能的影响;LQ最优控制作为跟随调节器可以保证系统的跟踪性能。仿真结果表明,设计的LQ—H∞混合控制器对参数摄动和负载扰动具有较强的鲁棒性,而且系统具有较强的跟踪性能。     

永磁同步电机H_∞鲁棒控制策略研究

永磁同步电机(PMSM)目前已得到广泛应用,普遍采用双闭环PI控制策略。在考虑到系统建模中的不确定性和负载扰动,基于凸极PMSM的数学模型,将控制器设计问题转化为H∞鲁棒控制标准型问题,通过选取适当的权函数并求解Riccati方程得到控制器参数。最后,通过实验证明所提出的H∞鲁棒控制策略具有良好的动静态性能。     

永磁直线同步伺服电机的零相位二自由度H∞鲁棒跟踪控制

针对永磁直线同步伺服电机(PMLSM)直接驱动伺服系统,提出了一种将零相位误差跟踪控制(ZPETC)和H∞鲁棒控制相结合的二自由度鲁棒跟踪控制策略,以解决系统的快速而精确的跟踪控制性能和抗扰性能之间的矛盾.零相位误差跟踪控制器保证了快速性,使系统实现准确跟踪;而H∞控制器克服了负载扰动等不确定性影响,保证了系统具有较强的鲁棒性能.仿真结果表明,该方案在保证伺服系统的快速精确跟踪性的同时,对系统参数变化和阻力扰动具有很强的鲁棒性.     

潜器全方位推进器主轴转速鲁棒H_∞控制器设计

针对潜器螺距调节式全方位推进器的工作环境和负载特性比较复杂的特点,为了提高全方位推进器主轴转速系统的动态性能和对参数扰动的鲁棒性,利用鲁棒控制理论,建立了永磁同步电机传动系统的反馈线性化模型,实现了主轴转速系统的鲁棒控制.该速度控制系统由负载转矩扰动估计器以及鲁棒控制器两部分构成.负载转矩扰动估计器主要用于负载扰动估计,以确保有效补偿负载扰动的影响.鲁棒控制器在电机参数发生变化和出现干扰的情况下,获得转速的跟踪性能.仿真结果表明,采用H∞鲁棒控制器的永磁同步电机主轴转速控制系统较传统的PID控制系统具有更好的跟踪性能、鲁棒稳定性和抗干扰性能.     

孤岛微电网频率μ-H∞鲁棒控制

针对孤岛交流微电网中风力、光伏发电的输出功率不确定性以及负荷的随机波动性引起的微电网频率波动问题,提出微电网频率μ-H∞鲁棒控制策略.所采用的μ-H∞鲁棒控制方法在传统H∞鲁棒控制方法解决外部扰动的基础上,考虑了系统结构不确定性对孤岛微电网系统频率稳定性的影响.建立具有时滞和不确定性的频率控制状态空间模型,基于鲁棒控制理论,将H∞控制器设计方法与μ综合D-K迭代法结合设计出μ-H∞频率鲁棒控制器,平抑因参数摄动、结构化不确定引起的频率波动,减小通信延时问题对微电网系统的影响.最后,通过Matlab/Simulink仿真软件和dSPACE半实物仿真平台,验证了所提控制方法在系统参数摄动、通信延时和结构不确定等情况下,均具有较好的动态性能和较强的鲁棒性.     

永磁直线同步电动机的变增益零相位H∞鲁棒跟踪控制

针对永磁直线同步伺服电机（PMLSM）直接驱动伺服系统,提出了一种将变增益零相位误差跟踪控制（VGZPETC）和H∞鲁棒控制相结合的鲁棒跟踪控制策略,以解决系统的快速而精确的跟踪性能和抗扰性能之间的矛盾.变增益零相位误差跟踪控制器克服了建模误差、系统参数变化等的影响,保证了快速性,使系统实现准确跟踪;而H∞控制器克服了负载扰动等不确定性影响,保证了系统具有较强的鲁棒性能.仿真结果表明,该方案在保证伺服系统的快速精确跟踪性的同时,对系统参数变化和阻力扰动具有很强的鲁棒性.     

基于扰动观测器和重复控制器的永磁直线同步电动机鲁棒控制

针对高精度直接驱动的永磁直线同步电动机伺服系统,研究其负载扰动、系统参数变化及端部效应等不确定性因素对系统伺服性能的影响,提出一种将扰动观测器(disturbance observer,DOB)和重复控制器(repetitive controller,RC)相结合的的鲁棒控制策略。基于DOB的鲁棒反馈控制器补偿了外部扰动、负载扰动、未建模动态、系统参数变化及不确定性等,保证了系统的速度鲁棒性能,但是DOB无法彻底抑制端部效应这种周期性扰动对速度品质的影响,为此,采用根据内模原理设计专门抑制周期性扰动作用的RC来消除端部效应对系统的不良影响。理论分析和仿真实验结果表明所提出的控制方案是有效的,采用该方案可明显提高系统的鲁棒性能。     

永磁直线同步电动机的变增益零相位H_∞鲁棒跟踪控制

针对永磁直线同步伺服电机(PMLSM)直接驱动伺服系统,提出了一种将变增益零相位误差跟踪控制(VGZPETC)和H∞鲁棒控制相结合的鲁棒跟踪控制策略,以解决系统的快速而精确的跟踪性能和抗扰性能之间的矛盾。变增益零相位误差跟踪控制器克服了建模误差、系统参数变化等的影响,保证了快速性,使系统实现准确跟踪;而H∞控制器克服了负载扰动等不确定性影响,保证了系统具有较强的鲁棒性能。仿真结果表明,该方案在保证伺服系统的快速精确跟踪性的同时,对系统参数变化和阻力扰动具有很强的鲁棒性。     

基于学习前馈补偿的直线伺服系统H∞鲁棒跟踪控制

针对直接驱动的永磁直线同步电机(PMLSM)伺服系统,在分析研究PMLSM的端部效应负载扰动及系统参数变化等不确定性因素对伺服系统性能影响的基础上,提出了一种将学习前馈控制和H∞鲁棒控制相结合的鲁棒跟踪控制策略.为消除端部效应的影响,采用基于B样条网络的学习前馈补偿控制技术,从而达到了良好的补偿效果;为克服不确定性扰动的影响,采用H∞鲁棒控制,从而保证系统有较强的鲁棒性.仿真结果表明,该方案保证了伺服系统快速而准确跟踪,同时有效地降低了不确定性扰动对系统性能的影响,从而提高了直线伺服系统的跟踪性能和鲁棒性能.     

基于H∞/m方法的永磁直线同步电机鲁棒二自由度控制

针对永磁直线同步电机(PMLSM)直接驱动伺服系统易受负载扰动、测量噪声及参数变化影响的特点，基于H￥/m方法设计了一个鲁棒二自由度速度控制器，解决了传统单自由度控制器在满足系统跟踪性能和抗干扰性能要求方面存在的矛盾。由于在求解m控制器时应用了标准H￥控制理论，大大提高了m控制器的获得速度。该速度控制器克服了标准H￥控制器保守性的缺点，并且对负载扰动、测量噪声和参数不确定性等干扰的抑制方面也比标准H￥控制器更具鲁棒性。仿真结果及分析表明，所提基于H￥/m方法二自由度速度控制器，满足高精度永磁直线同步电机伺服系统对鲁棒性和快速性的要求。     

Robust decentralized neural networks based LFC in a deregulated power system

In this paper, a decentralized radial basis function neural network (RBFNN) based controller for load frequency control (LFC) in a deregulated power system is presented using the generalized model for LFC scheme according to the possible contracts. To achieve decentralization, the connections between each control area with the rest of system and effects of possible contracted scenarios are treated as a set of input disturbance signals. The idea of mixed H₂/H_∞ control technique is used for the training of the proposed controller. The motivation for using this control strategy for training the RBFNN based controller is to take large modeling uncertainties into account, cover physical constraints on control action and minimize the effects of area load disturbances. This newly developed design strategy combines the advantage of the neural networks and mixed H₂/H_∞ control techniques to provide robust performance and leads to a flexible controller with simple structure that is easy to implement. The effectiveness of the proposed method is demonstrated on a three-area restructured power system. The results of the proposed controllers are compared with the mixed H₂/H_∞ controllers for three scenarios of the possible contracts under large load demands and disturbances. The resulting controller is shown to minimize the effects of area load disturbances and maintain robust performance in the presence of plant parameter changes and system nonlinearities.     

为提高轮廓加工精度采用DOB和ZPETC的直线伺服鲁棒跟踪控制

为了提高轮廓加工精度,本文针对高精度直线伺服系统,提出了一种将零相位误差跟踪控制器(ZPETC)和干扰观测器(DOB)相结合的鲁棒跟踪控制策略.ZPETC作为前馈跟踪控制器,保证了快速性,使系统实现准确跟踪;基于DOB的鲁棒反馈控制器补偿了外部扰动、未建模动态、系统参数变化和机械非线性等,保证了系统的强鲁棒性能.仿真结果表明了所提出的控制方案是有效的,既能实现完好跟踪,又有较强的鲁棒性能.从而有效地减小了轮廓误差,提高了轮廓加工精度.     

Comparison of different robust control methods in design of decentralized UPFC controllers

The unified power flow controller (UPFC) integrates properties of both shunt and series compensations, and can effectively alter power system parameters in such a way that increases power transfer capability and enhances system stability. In practice, simple proportional–integral (PI) controllers are used to control the UPFC. However, the PI control parameters are usually tuned based on classical or trial-and-error approaches and as such, they are incapable of obtaining good dynamic performance for a wide range of operating conditions and various loads in power systems. Hence, in this article robust control approaches are proposed based on the quantitative feedback theory (QFT), H_∞ loop-shaping and μ-synthesis, to design UPFC controllers (power-flow and DC-voltage regulator). The three mentioned methods are compared with each other and a supplementary damping controller is developed to improve damping power system oscillations. Here, a single-machine infinite-bus (SMIB) power system, installed with a UPFC (with system parametric uncertainties) is considered as a case study. The system parametric uncertainties are obtained following 40% simultaneous alterations in parameters and load from their typical values. The simulation results indicate satisfactory verifications of the robust control methods in dealing with the uncertainties considered. When the above three methods and the PI controller are compared in performance in several time-domain simulation tests, the results show clear superiority of the three methods over the PI controller, with the QFT presenting the best performance amongst the three robust control.     

STATCOM无功电流的鲁棒自适应控制

从器件级、装置级和系统级3个层次讨论电压源型STATCOM的数学建模和控制器设计;提出了一种鲁棒型直接自适应控制算法,以解决STATCOM模型参数未知情况下无功电流的追踪控制问题。在对象系统严格正实性得以验证的基础上,系统地选择了控制器设计参数,并考虑了输入输出噪声对控制系统的影响,从而使控制器具有较好的鲁棒性。数字仿真结果表明,得到的控制器在追踪控制能力和鲁棒特性等方面比PI控制优越。     

基于鲁棒方差优化的电力系统频率控制研究

随着新能源发电大规模并网,随机负荷扰动给电力系统稳定优化运行提出了新的挑战。针对自动发电控制过程中存在的随机扰动和参数摄动的问题,提出了一种基于鲁棒方差约束的状态反馈控制器的参数优化方法。根据鲁棒方差控制(Robust Variance Control,RVC)中不等式约束条件,分析了闭环系统在抑制随机扰动和提高阶跃扰动响应动态性能之间的博弈关系。构造了融合稳态状态方差和控制能量输出约束的优化问题,利用线性矩阵不等式(Linear Matrix Inequality,LMI)获得了鲁棒方差控制器参数。在此基础上,对配置的区域极点圆心坐标值和正标量两个参数进行遗传优化,得到性能指标最优的控制策略。以两区域电力系统模型为例,表明该方法能够有效抑制随机扰动并保持良好的控制性能和鲁棒性能。     

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.     

Decentralized robust adaptive load frequency control using interactions estimation

In this paper, a new model reference decentralized adaptive output feedback controller is proposed for load-frequency control (LFC) of large-scale power systems with unknown parameters. The main problem with a decentralized robust LFC is that the interactions are treated as disturbances. This results in a conservative control action to maintain stability in the worst-case scenario. Furthermore, to improve the performance of the decentralized LFC, the proposed method estimates the interactions from other subsystems to modify the adaptive controller so that the interactions are effectively neutralized. The other important features of the proposed controller are: (1) no prior information about the system parameters is required, (2) random changes in the operating conditions are traced, (3) only the local input–output data are needed, (4) the robustness of the overall system against the system parameter uncertainties is guaranteed. To show the effectiveness of the proposed controller, a three-area power system is studied. The simulation results are promising and highlight the remarkable performance of the controller even in the presence of both plant parameter changes and high interactions.     

Robust adaptive control of nonlinearly parameterized systems with unmodeled dynamics

Many physical systems such as biochemical processes and machines with friction are of nonlinearly parameterized systems with uncertainties. How to control such systems effectively is one of the most challenging problems. This paper presents a robust adaptive controller for a significant class of nonlinearly parameterized systems. The controller can be used in cases where there exist parameter and nonlinear uncertainties, unmodeled dynamics and unknown bounded disturbances. The design of the controller is based on the control Lyapunov function method. A dynamic signal is introduced and adaptive nonlinear damping terms are used to restrain the effects of unmodeled dynamics, nonlinear uncertainties and unknown bounded disturbances. The backstepping procedure is employed to overcome the complexity in the design. With the proposed method, the estimation of the unknown parameters of the system is not required and there is only one adaptive parameter no matter how high the order of the system is and how many unknown parameters there are. It is proved theoretically that the proposed robust adaptive control scheme guarantees the stability of nonlinearly parameterized system. Furthermore, all the states approach the equilibrium in arbitrary precision by choosing some design constants appropriately. Simulation results illustrate the effectiveness of the proposed robust adaptive controller. __________ Translated from Journal of Sichuan University (Engineering Science Edition), 2005, 37(5): 148–153 (in Chinese)