考虑广域信息时延影响的H∞阻尼控制器

广域控制策略可以有效提高广域分布互联电力系统的动态性能,但是广域控制信号传输时延会对控制器产生负面影响,并且日趋复杂的系统结构及接近稳定极限的运行条件对控制器的鲁棒性能提出了更高的要求。该文在考虑信号传输时延的情况下建立了电力系统状态空间模型,并应用H∞回路成形及规范互质分解技术对上述模型进行了鲁棒镇定控制器设计。得到的控制器不仅具有很强的鲁棒性能,同时可使闭环系统容忍更大的时延。以时域仿真结果说明了所得控制器的性能及方法的有效性。     

A novel robust current control approach using adaptive line enhancer for three‐phase current‐source active power filter

An effective system control method is presented for applying a three‐phase current‐source PWM converter with a deadbeat controller to active power filters (APFs). In the shunt‐type configuration, the APF is controlled such that the current drawn by the APF from the utility is equal to the current harmonics and reactive current required for the load. To attain the time‐optimal response of the APF supply current, a two‐dimensional deadbeat control scheme is applied to APF current control. Furthermore, in order to cancel both the delay in the two‐dimensional deadbeat control scheme and the delay in DSP control strategy, an Adaptive Line Enhancer (ALE) is introduced in order to predict the desired value three sampling periods ahead. ALE has another function of bringing robustness to the deadbeat control system. Due to the ALE, settling time is made short in a transient state. On the other hand, total harmonic distortion (THD) of source currents can be minimized compared to the case where ideal identification of the controlled system can be made. The experimental results obtained from the DSP‐based APF are also reported. The compensating ability of this APF is very high in accuracy and responsiveness although the modulation frequency is rather low. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 50–61, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20014     

A novel adaptive control approach for nonlinearly parameterized systems

Nonlinearly parameterized systems are commonly encountered in control of practical systems. However, the conventional adaptive estimation and control strategies, based on the essential assumption of linear parameterization, are incapable of dealing with this class of systems. This incapability in turn becomes a bottleneck for prevalent applications of adaptive control. In literature, there have been some attempts to break through this bottleneck by investigating the characteristics of nonlinearities. However, it is still open for an implementable strategy that is powerful for nonlinearly parameterized systems as the certainty equivalence principle for linearly parameterized systems. This paper aims to contribute an attempt to this open problem by proposing a novel adaptive control approach. On the one hand, the controller is conceptually simple, and it does not explicitly rely on the expression of system nonlinearities. On the other hand, the controller is able to achieve system stability and parameter convergence. Copyright © 2013 John Wiley & Sons, Ltd.     

Reactive power pricing: a conceptual framework for remuneration andcharging procedures

A new electrical sector regulation is being implemented in different countries all over the world. The new regulation stresses the role of competitive markets for the procurement and remuneration of ancillary services. Among these services stand the ones associated with reactive power supply and transmission network voltage control in order to maintain the required system security levels. The object of this paper is twofold. On one hand, reactive power supply and voltage control services, which today are bundled, are decomposed in two types: (i) voltage profile management and reactive dispatch, and (ii) voltage regulation. A theoretical approach based on marginal pricing is proposed in order to clarify the principles to remunerate the suppliers and to charge the consumers of these services. On the other hand, a practical organization of reactive supply and voltage service markets is presented to be implemented in a competitive environment     

可编程门阵列在无刷直流电机控制中的应用

随着微电子工艺向深亚微米发展,使在一个芯片中可以集成很大的系统成为可能,另外较大门数的可编程逻辑器件的出现为实现这种系统提供了方便和经济的途径。该文详细介绍了可编程门阵列器件(FPGA)及其在无刷直流电机控制系统中的应用。FPGA的使用简化了系统结构,提高了系统工作的稳定性和可靠性。本系统利用硬件描述语言VHDL设计在片内实现电机控制逻辑。软件仿真和试验结果均表明输出波形稳定、精确。该系统已成功应用于机器人仿人灵巧手指中。     

QUANTUM PLC双机热备技术在首钢迁钢公司7000风机自控系统中的应用

鼓风机担负着为高炉提供动力能源的重要任务,因此.要求鼓风机控制系统要具有非常高的稳定性和安全性,特别是选择技术成熟,稳定性好的控制系统尤为重要。本文一方面详细介绍了QUANTUM PLC双机热备技术在首钢迁钢公司7000风机自动控制系统中的应用,包括主要设备的选型,软硬件的组态,重要参数的设定等,另一方面还结合7000风机的应用实例,剖析了双机热备系统在使用中常见的问题和处理方法。     

一种改进型Smith预估控制器的设计与仿真

通过分析钢厂轧钢车间工件加热系统[1]的结构,并针对该加热系统大迟延、模型不精确的特点,介绍了一种改进型Smith预估控制器的控制策略,并对实际对象的模型进行仿真分析,结果表明此控制策略能很好地改善控制系统的动态特性,并具有很强的鲁棒性.     

A Novel Grid Synchronization Control of Doubly-fed Induction Generator

The dynamic performance of doubly-fed induction generator(DFIG) before and after connection is analyzed based on corresponding mathematical models and transfer functions in decoupled vector control.The parameter tuning methods of rotor current regulator before and after connection are given.To reach same dynamic performance the parameters should take different values and be switched before and after connection.However on one hand the closing moment of stator contactor is difficult to get as the feedback signal is usually twenty millisecond delay or so.The delay in parameter switching will affect rotor current and torque dynamics during the delayed period after connection. On the other hand parameter switching is troublesome.Hence a synchronization control strategy without parameter switching is proposed and analyzed in detail,which has linear rising exciting current to avoid current overshooting. The dynamic performance of the proposed strategy is analyzed in frequency domain and implemented on a DFIG experimental platform subsequently.The proposed synchronization strategy is validated by experimental results.     

热轧厂改造后粗轧区数据跟踪管理

数据跟踪管理系统是带钢热连轧自动控制系统中非常重要的一部分.一方面,它确保每块板坯按二级系统为其设定的参数进行轧制;另一方面,将轧制过程中对应于每一块板坯的实测数据反馈回二级系统完成后续区域的设定、跟踪和自学习等处理.粗轧区数据跟踪管理是整个热连轧生产过程中数据跟踪管理系统不可或缺的一部分,详细介绍该钢厂粗轧区数据跟踪管理的实现方法.     

EMS-Vision: a perceptual system for autonomous vehicles

The paper gives a survey on the new Expectation-based Multifocal Saccadic vision (EMS-vision) system for autonomous vehicle guidance developed at the Universitat der Bundeswehr Munchen (UBM). EMS-Vision is the third generation dynamic vision system following the 4-D approach. Its core element is a new camera arrangement, mounted on a high bandwidth pan-tilt head for active gaze control. Central knowledge representation and a hierarchical system architecture allow efficient activation and control of behavioral capabilities for perception and action. The system has been implemented on commercial off-the-shelf (COTS) hardware components in both UBM test vehicles VaMoRs and VaMP Results from autonomous turnoff maneuvers, performed on army proving grounds, are discussed     

一类网络控制系统的建模与稳定性分析

针对一类具有不确定网络诱导时延和线性控制对象的网络控制系统,通过将网络诱导时延描述为一个常值再叠加一个不确定值的形式,重新描述了采样控制系统的数字控制器,将网络控制系统建模为一类具有不确定时延的连续时间系统.利用Lyapunov方法和线性矩阵不等式技术,推导出了闭环系统渐进稳定的充分条件.与已有的结果相比,所提出的算法具有更低的保守性,并通过一个数值算例验证了所提出算法的有效性.     

The Berlin Brain-Computer Interface: EEG-based communication without subject training.

The Berlin Brain-Computer Interface (BBCI) project develops a noninvasive BCI system whose key features are 1) the use of well-established motor competences as control paradigms, 2) high-dimensional features from 128-channel electroencephalogram (EEG), and 3) advanced machine learning techniques. As reported earlier, our experiments demonstrate that very high information transfer rates can be achieved using the readiness potential (RP) when predicting the laterality of upcoming left- versus right-hand movements in healthy subjects. A more recent study showed that the RP similarily accompanies phantom movements in arm amputees, but the signal strength decreases with longer loss of the limb. In a complementary approach, oscillatory features are used to discriminate imagined movements (left hand versus right hand versus foot). In a recent feedback study with six healthy subjects with no or very little experience with BCI control, three subjects achieved an information transfer rate above 35 bits per minute (bpm), and further two subjects above 24 and 15 bpm, while one subject could not achieve any BCI control. These results are encouraging for an EEG-based BCI system in untrained subjects that is independent of peripheral nervous system activity and does not rely on evoked potentials even when compared to results with very well-trained subjects operating other BCI systems.     

高功率脉冲能源装置监控系统的研制

针对脉冲功率技术中对Marx充电的能源设备及触发装置的自动化控制,介绍了一种基于虚拟仪器技术的高功率脉冲能源装置监控系统的研制。系统采用可编程高功率交流电源产生连续可调工频电压,经过高压变压器及硅堆等装置变换为直流高压,对Marx进行双极性的线性充电。主控计算机通过RS-485串口方式对可编程交流电源及数字延时触发设备进行实时状态监测及远程控制,采用VB6.0软件作为开发平台,并利用NI控件等完成了能源设备的虚拟数字化调压测控和数字延时触发等功能设计。为了减小实验现场高电压、大电流等形成的强电磁干扰对系统的影响,系统软硬件都融入了可靠性设计。整个监控系统应用灵活、工作可靠、实时性强、操作简单,具有可扩展性,是脉冲功率装置中自动控制技术应用的有益探索。     

Load-flow equivalents for decentralized monitor and control of power systems

Load-flow calculation on electric power systems is one of the most fundamental analyses in system operation and planning. There are many reasons to calculate load-flow solutions, and the contingency evaluation is a representative one. In contingency evaluation, it is necessary to repeat load-flow calculation for tremendous patterns depending on branch or generation outages. Then, computing efforts are generally very heavy. Thus various techniques have been proposed to reduce computing time, especially by adopting equivalencing for external network. On the other hand, the network equivalents techniques also become important at present from the viewpoint of the necessity of decentralized monitor and control on bulk power systems. This paper describes a newly developed method of load-flow equivalents based on the Ward equivalent for both direct (dc) solution and (ac) solution. Numerical results also are shown to clarify the accuracies and practicality of the proposed method through the comparison of the representative REI approach.     

内模网络控制系统稳定性

在网络控制系统中随机延时的存在使系统的性能变差甚至不稳定.本文重点分析内模网络控制系统中存在的延时对系统性能的影响;从连续系统、状态空间的角度出发利用劳斯稳定性判据、李亚普诺夫方法判断系统的稳定性,给出了保持系统稳定的最大允许延时阈值.为了使内模网络控制系统获得良好的性能,在内模网络控制系统中加入延时预测环节,并分析了延时预测对系统稳定性的影响.仿真表明本文提出方法的有效性.     

Adaptive time-varying formation control for teleoperation system: A finite-time approach

In this article, the finite-time formation control scheme is put forward for teleoperation system with time delay. First, a group of finite-time observers are established to address the teleoperation system with time-varying delay issue and via linearly parameterize to deal with the uncertainty in the system. The theory of self-stable domain (SSR) is then applied to provide sufficient circumstances for the observers error dynamics to converge in finite-time. Then, in line with the estimation of time delay derivatives to reconstruct the regression matrix as well as the adaptive law, the observer based time-varying formation control protocol is drawn up. On the basis of finite-time state-independent input-to-output practical stable (FTSIIOpS) theorem, sufficient conditions for teleoperation implement time-varying formation are developed. Finally, simulation is being used to validate the efficiency of the proposed strategy.     

磁悬浮轴承数字控制的稳定性分析及预补偿算法

采用数字控制技术取代传统的模拟控制是磁悬浮轴承控制技术的发展方向。但数字控制器固有的时延现象会严重影响控制器的品质,甚至引起控制器工作的失败。本文在研究了磁悬浮轴承数字控制时延的组成及其对控制系统性能影响的基础上提出了一种新的时延补偿算法,该算法通过预测下一采样时刻的系统输出来消除时延对控制系统的影响。预测算法由磁悬浮轴承的离散化模型得到,算法系数由神经网络修正。实验结果表明该算法能够很好地补偿数字控制器的时延,实现了数字控制磁悬浮轴承的稳定悬浮和旋转。     

广域测量系统分段时延测量及分析

广域测量系统(WAMS)的测量数据和管理数据均通过电力调度数据网传输,数据传输过程中在各个阶段引入的时延具有不确定性和随机性,对广域电力系统阻尼控制造成非常不利的影响。为此,提出一种对WAMS分段时延的测量方法,该方法可以有效地测量WAMS数据传输过程中各环节的时延,为保证WAMS数据的实时性和正确性提供了分析依据。在浙江省现场安装并搭建了该方法的应用平台,测量了实际现场中WAMS的分段时延并针对分段时延的特性与影响因素进行了分析。结果表明,所提出的WAMS分段时延测量方法能有效测量WAMS分段时延,通过对现场分段时延的测量和分析,为WAMS总体时延的改善提供明确的方向。     

Free‐weighting matrices‐based robust wide‐area FACTS control design with considering signal time delay for stability enhancement of power systems

This paper presents a free‐weighting matrix (FWM) method based on linear control design approach for the wide‐area robust damping (WARD) controller associated with flexible AC transmission system (FACTS) device to improve the dynamical performance of the large‐scale power systems. First, the linearized reduced‐order plant model is established, which efficiently considers the time delay of the remote feedback signals transmitted by wide‐area measurement systems. Then, based on the robust control theory, the design of the FACTS‐WARD controller is formulated as the standard control problem on delay‐dependent state‐feedback robust control, which is described by a set of linear matrix inequality constraints. Furthermore, in order to obtain the optimal control parameters that can endure the maximum time delay, a FWM approach is proposed to solve the time‐dependent problem of the time‐delay system. Meanwhile, an iterative algorithm based on cone complementary linearization is presented to search out the optimal control parameters. Finally, the nonlinear simulations on the 2‐area 4‐machine and the 5‐area 16‐machine test systems are performed, to evaluate the control performance of the proposed robust wide‐area time‐delay control approach. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

雷击变电站引起的电源干扰问题

电力系统中微机保护和综合自动化系统中的微电子元件对干扰特别敏感,而由雷电产生的电源干扰危害严重.针对电源干扰产生的途径、机理进行分析和研究,建立相应的分析模型,对微机测控回路的电容耦合干扰、弱电系统的感性耦合干扰以及阻性耦合干扰的机理作较深入地研究,并在基础上提出抗干扰的技术措施.