Loop shaping of multivariable systems with hard constraints on the control signal

Contents   A general framework for the design of multivariable control systems subject to hard constraints on each control channel is developed. The design procedure is based on the ℋ_∞ loop shaping and relies on the calculation of the maximum possible control amplitude for a class of reference signals, bounded in amplitude and rate. Special attention is given to adjustment of the design weights in order to meet prescribed bounds on each control signal. A simulation example, the control of the vertical dynamics of an aircraft, illustrates the suggested procedure. Received: 2 May 2001     

A scheduled controller design of congestion control considering network resource constraints

In this paper, we consider a dynamical model of computer networks and derive a synthesis method for congestion control. First, we present a model of TCP/AQM (Transmission Control Protocol/Active Queue Management) as a dynamical model of computer networks. The dynamical model of TCP/AQM networks consists of models of TCP window size, queue length, and AQM mechanisms. Second, we propose to describe the dynamical model of TCP/AQM networks as linear systems with self‐scheduling parameters, which also depend on information delay. Here we focus on the constraints on the maximum queue length and TCP window size, which are the network resources in TCP/AQM networks. We derive TCP/AQM networks as the LPV system (linear parameter varying system) with information delay and self‐scheduling parameter. We design a memoryless state feedback controller of the LPV system based on a gain‐scheduling method. Finally, the effectiveness of the proposed method is evaluated by using MATLAB and the well‐known ns‐2 simulator (Network Simulator Version 2). © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 61–68, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10341     

船舶发电机分散励磁鲁棒控制器设计

为了提高船舶电力系统的抗干扰能力和稳定性,设计了分散励磁式船舶发电机系统的鲁棒控制器,建立了柴油机发电机组的数学模型,明确了模型中干扰项的物理意义。在将发电机组数学模型线性化并增广为广义受控系统后,应用H∞控制理论,设计了发电机的分散励磁鲁棒控制器,并应用线性矩阵不等式方法求解了控制器的解。通过仿真试验,比较了传统的电力系统稳定（PSS）控制器和分散励磁鲁棒控制器的控制效果,表明后者具有更好的抗干扰能力,提高了船舶电力系统的稳定性。     

基于鲁棒调节器的无刷直流电机速度控制研究

本文提出了无刷直流电机的一种线性时变模型，分析了影响电机速度控制的负载扰动，在此基础上，设计了一种鲁棒速度控制器，对其设计方案进行了阐述，同时，针对速度不易检测的问题设计了全维转速观测器，最后，对速度控制系统进行了实验研究。     

Robust STATCOM voltage controller design using loop-shaping technique

Static synchronous compensator (STATCOM) is a shunt-connected converter, which can affect rapid control of reactive flow in the transmission line by controlling the generated a.c. voltage. This article presents a robust STATCOM voltage controller design for power system damping. The method of multiplicative uncertainty has been employed to model the variations of the operating points. The design is carried out applying robustness criteria for stability and performance. A loop-shaping technique has been employed to select a suitable open-loop transfer function, from which the robust controller function is constructed. The controller was tested for a number of disturbances including three-phase fault. The damping provided by the robust controller was compared with a fixed-parameter PID controller, whose gains were calculated through a pole-placement technique. It has been observed that the PID control is ineffective at operating points other than nominal. The robust design has been demonstrated to provide extremely good damping characteristics over a range of operating conditions.     

基于模糊控制的PAC控制器的设计

在工业制造生产过程中,对控制的需求越来越高。PAC是一种新型的可编程自动化控制器,在控制性能、信息处理以及网络通信能力具有一些比较显著的优点。PAC控制器结合了PLC固有的可靠性、坚固性和分布特性,同时与PC控制相比,PAC使用实时操作系统,在处理性能上具有实时性、确定性等PC机不可比拟的优点。在传统PAC控制器的基础上,采用了改进PID控制算法、自整定模糊PID控制算法,能够提高控制精度、提高控制响应、满足更高的控制要求。     

Robust performance design of a state predictive controller on parameter space

Robust performance against a multiplicative uncertainty is an important measure for closed‐loop performance. In this article, a parameter space design method of a state predictive controller is proposed for second‐order time‐delay systems. The boundaries of two permissible regions of state feedback gains and observer gains that satisfy the robust performance condition at each frequency are obtained. An appropriate solution can be found after a few iterations by drawing the regions on the two parameter planes, alternatively. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

鲁棒HMRAC控制器设计及在镗床电机控制中的应用

设计了一种任意相对阶数的鲁棒HMRAC系统,采用补偿多项式,取消了文献[1]中要求系统相对阶数不大于2的限制条件;采用可调线性补偿器,取消了系统参数变化范围已知的假定条件;扩展了应用范围。基于混合误差模型,避免了系统因离散化而引起的非最小相位问题及扰动影响。该系统到镗床电机控制中,验证了方案的有效性。     

参数不确定广义系统鲁棒H∞容错控制器的设计

研究了一类不确定广义系统基于状态反馈针对执行器发生故障的鲁棒H∞容错控制问题；运用线性矩阵不等式(LMI)给出了鲁棒H∞容错控制器存在的充分条件；通过假设失效的执行器的输出信号是任意的能量有界干扰信号，将不确定广义系统的鲁棒H∞容错控制问题化为H。控制问题，给出了该问题可解性的充分奈件。鲁棒H∞容错控制器可以通过解相应的线性矩阵不等式(LMI)给出，因而具有数值易解性。最后，所给的设计例子说明了方法的有效性。     

Robust SVC controller design for improving power system damping

The design of a robust controller for a static VAr compensator (SVC) to improve the damping of a power system is presented. The main contributions of the paper are to formulate and to solve the power system damping control problem using robust optimization techniques, and to synthesize the controller with explicit consideration of the system operating condition variations. Nonlinear simulations using the PSCAD/EMTDC software packages have been conducted to evaluate the performance of the closed-loop system. The results have indicated that the designed controller can provide positive damping to the system under a wide range of operating conditions     

基于迭代学习控制理论的励磁控制器设计

基于迭代学习控制理论提出了一种设计单机无穷大系统励磁控制器的新方法,克服了迭代学习控制在有限时间区间上实现完全跟踪的限制。将迭代学习控制对输出控制量u(t)的记忆与修正改成对期望控制ud(t)的记忆与修正,采用最小二乘法拟合控制器参数,使设定的控制与期望控制之差达到最小,求得控制律。用Matlab对发电机励磁控制系统进行仿真研究,结果表明所设计的励磁控制器具有较好的动态特性和较强的鲁棒性。     

Robust controller design for large interconnected power systems with model uncertainties based on wide-area measurement

Recently the controller using wide-area measurement systems (WAMS) signals has been suggested to accommodate the dynamic performances of large interconnected power systems. However, there is an unavoidable delay before the wide-area signals are received at the controller site. Therefore, a delay-independent robust control problem of large interconnected power systems is studied via H _∞ fuzzy control method based on wide-area measurement. First, a set of equivalent Takagi–Sugeno (T–S) fuzzy model is adopted to represent the nonlinear large interconnected power system. A wide-area state feedback decentralized H _∞ fuzzy control scheme is developed to override the various disturbances, solve the effect of model uncertainties and stabilize the large power system. The H _∞ decentralized control problem is parameterized in terms of a linear matrix inequality (LMI) problem, and the LMI problem can be solved efficiently using convex optimization techniques. Finally, the effectiveness of the proposed controller design methodology is demonstrated through simulation example. This work is supported by the National Science Foundation of China under grant 60374039, 60404007.     

基于Riccati法的舰船电力系统鲁棒励磁控制研究

介绍了鲁棒控制器设计的Riccati方法，建立了单台发电机工作的典型工况下舰船电力系统的数学模型，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。     

基于区间分析的参数不确定系统PID鲁棒控制器设计

针对区间对象PID鲁棒控制器设计问题,提出了一种基于广义Kharitonov定理和区间分析集逆算法的设计方法。该方法根据广义Kharitonov定理将区间对象的鲁棒稳定控制器综合问题转化为多个顶点对象同时稳定的控制器综合问题,根据劳斯判据得到与控制器参数相关的不等式组,采用基于区间分析的集逆算法求解该不等式组得到PID鲁棒控制器参数。数值算例表明所提出的设计方法可以以任意设定精确度逼近使得整个区间对象族稳定的PID控制器参数域,与传统图解法相比求得的结果是可靠的,同时该方法能够根据集逆算法解集情况准确判断假定的控制器是否可行。     

Reference controller design in 2-DOF control

This paper deals with the design of the reference controller on a 2-DOF controller configuration with respect to the optimization of a linear quadratic Gaussian (LQG) type cost function. Although different configurations have been used in the literature, here we would like to show the particular advantages of using a special control configuration that allows a complete separated and independent design of the feedback and reference part of the controller. Results concentrate on the SISO case and exploit the polynomial approach to the solution of the LQG problem.     

利用LMI技术设计多机系统TCSC鲁棒控制器

可控串联电容补偿器(TCSC)装设在高压线路上可改善系统的暂态稳定性,提高线路的传输容量。指出传统的H∞控制理论在电力系统中的应用需要计算Gamma迭代的优化问题,而线性矩阵不等式(LMI)技术为多个目标控制器的设计提供了新途径,设计指标与约束条件等可表达成LMI形式,可用有效的凸优化算法得到精确解答。提出了借鉴有极点区域配置约束的混合H2/H∞问题的LMI解法,设计了应用于多机系统的TCSC的鲁棒控制器。应用安德森3机9节点系统模型测试了所提方法的鲁棒性,在测试了小规模突发事件仿真、小规模突发事件的鲁棒TCSC控制器性能的结果后表明,TCSC控制器利用LMI方法可实现鲁棒稳定和快速反应。     

电网电压不对称时双馈电机鲁棒控制器设计方法

介绍了一种基于H∞鲁棒控制理论的双馈电机(DFIG)电流控制器设计方法,可用于提高双馈风力发电机在电网电压不对称条件下的运行性能。首先从减小电流畸变或者抑制功率二倍工频脉动的角度出发,根据正负序分解理论得到了转子负序电流补偿控制策略;然后给出了双馈电机H∞电流控制器的设计过程,并详细分析了控制器性能的限制条件与相应权函数的选择方法。通过μ分析发现,与通常使用的PIR控制相比,本文所提H∞控制器具有受系统参数和运行状态变化影响小、鲁棒稳定性高的优点,并且能够更加有效地抑制定子固有振荡模态,减弱不对称电压跌落时的过渡过程。最后通过仿真验证了本文所提方法的有效性。     

Robust analysis and design of load frequency controller for power systems

Robust load frequency control for power systems is discussed. A detailed robustness analysis of the existing control laws shows that parameter variation is not a critical issue but more attention should be paid to the unmodeled dynamics in robust load frequency controller design. A new robust load frequency control method is then proposed considering the unmodeled dynamics of power systems. Finally, a new configuration is proposed to overcome the effects of generation rate constraints (GRC). Simulation results show that the design method and the anti-GRC configuration are effective.     

Robust and simple adaptive control system design

Recently, the simple adaptive control (SAC) method has attracted considerable interest because of the simple structure of its adaptive controller. The method can only be applied to plants with so-called almost strictly positive real (ASPR) characteristics. Unfortunately, most real plants do not satisfy this condition. Furthermore, real plants contain disturbances such as uncertain elements. This paper deals with such problems and proves that the implementation of a parallel feedforward compensator makes it possible to apply the SAC method to non-ASPR SISO plants with plant uncertainties. Furthermore, a robust SAC algorithm in the presence of a class of external disturbances is also considered. The effectiveness of the parallel feedforward compensator and robust adaptive controller designed in this way is examined through several numerical simulations.     

Multivariable controller design in an adaptive control scheme

A multivariable control system design approach in the frequency domain is presented. The issue of control system redesign in an adaptive control scheme is discussed. Expert system techniques have been used for the automated design of controllers for multivariable systems. Design knowledge has been represented using rules, facts and objects. The design process consists of a sequence of operations obtained by heuristics and experience in the the design techniques. An automated design session of a multivariable plant using the expert system demonstrates that the expert system appears to work well in its prototype implementation.