Teleoperation via computer network

In a teleoperation system, providing force information to a human operator can improve task performance. When a communication block between a master and a slave has a transmission delay, the system is easily destabilized. Anderson and Spong guaranteed passivity in the communication block by using scattering transformation and overcame this instability caused by the time delay. But this method can be applied to the communication block with a constant time delay. In a traditional teleoperation system, its communication block has a constant time delay. But time delay irregularly changes in a computer network because many users share telecommunication lines. This paper shows that the variable time delay destabilizes bilateral master-slave manipulator with scattering transformation and a new compensation method which keeps the time delay constant. This new compensation method has been implemented in a single-axis master-slave manipulator.     

Performance Comparison of Circuits for Pole‐Mounted STATCOM Using SiC Devices

The recent years have seen an increasing trend in the cumulative installed capacity of distributed generators. As a result, voltage management may become difficult in existing power distribution systems in the future. A STATCOM (STAtic synchronous COMpensator) is a promising option for solving this problem because it can control reactive power rapidly and continuously. For a distribution system, STATCOM needs to be pole‐mounted to realize its low cost. However, a transformer for a STATCOM is large and heavy, and hence it is difficult to install a STATCOM on a distribution pole. We adopt a transformerless STATCOM to reduce STATCOM size and use SiC devices with low‐loss performance to obtain a more compact and efficient STATCOM. There are a large number of circuits available for a STATCOM, and there has been considerable research on performance comparisons among these circuits. However, these comparisons were drawn under different conditions, including switching frequency and level number for the circuits. In addition, these comparisons do not include the use of SiC devices. We made an equitable comparison for a 100 kVa pole‐mounted STATCOM using SiC devices. We discuss the performance and characteristics of each circuit in terms of efficiency and volume.     

Unit commitment using Lagrangian relaxation and particle swarm optimization

Unit commitment (UC) is a NP-hard nonlinear mixed-integer optimization problem. This paper proposes ELRPSO, an algorithm to solve the UC problem using Lagrangian relaxation (LR) and particle swarm optimization (PSO). ELRPSO employs a state-of-the-art powerful PSO variant called comprehensive learning PSO to find a feasible near-optimal UC schedule. Each particle represents Lagrangian multipliers. The PSO uses a low level LR procedure, a reserve repairing heuristic, a unit decommitment heuristic, and an economic dispatch heuristic to obtain a feasible UC schedule for each particle. The reserve repairing heuristic addresses the spinning reserve and minimum up/down time constraints simultaneously. Moreover, the reserve repairing and unit decommitment heuristics consider committing/decommitting a unit for a consecutive period of hours at a time in order to reduce the total startup cost. Each particle is initialized using the Lagrangian multipliers obtained from a LR that iteratively updates the multipliers through an adaptive subgradient heuristic, because the multipliers obtained from the LR tend to be close to the optimal multipliers and have a high potential to lead to a feasible near-optimal UC schedule. Numerical results on test thermal power systems of 10, 20, 40, 60, 80, and 100 units demonstrate that ELRPSO is able to find a low-cost UC schedule in a short time and is robust in performance.     

基于KNX总线智能家居控制系统的设计

智能家居控制系统品牌种类繁多,合适的家居系统才会给住户带来舒适的生活环境。基于KNX的智能家居系统,操作方便、采用便捷的总线配置、扩充性强、可靠性高,同时节能效果好,营造了良好的家居氛围。就家居中灯光、窗帘、AV、安防等方面的控制进行设计和调试,实践检验证明,使用效果良好。     

Single transistor high linearity and wide dynamic range active inductor

In this paper, an active inductor (AI) with high linearity and high dynamic range, including a minimum number of components, is presented. The AI is composed by a single transistor, and by a passive compensation network; the latter allows the control of the values of both the inductance and the series resistance. In order to show the feasibility of the proposed AI for filter applications, a prototype board on a TLX8 substrate with a first‐order active band‐pass filter has been fabricated and tested. The filter has a center frequency of 2470 MHz (useful for Bluetooth applications) and a measured noise figure (NF) of 9 dB with a ?5 dBm P₁dB compression point, and a 75 dB dynamic range. Copyright © 2013 John Wiley & Sons, Ltd.     

单元机组协调系统的非线性内模控制

协调系统的性能直接影响单元机组运行的安全性和经济性。为了克服非线性环节以及能量供需之间关联耦合作用对协调系统控制品质的影响，本文将反馈线性化方法与多变量内模控制结构结合，针对一个通用的非线性协调系统模型，设计出非线性内模协调控制器。文中分析了多变量非线性内模控制结构的鲁棒稳定性及动态性能。在不同负荷下的仿真试验表明，所设计的控制系统具有良好的解耦效果和抗干扰能力。     

评价随机混合容量网络脆弱性的一种新方法

本文将讨论随机混合容量网络的脆弱性、提出了改进边失效概率,改进边容量两个新概念,给出了把一个顶点分解为两个顶点与一条边组合的分解方法。利用这两个新概念和分解法,可以把一个随机混合容量网络转换为一个定常边容量网络,从而利用度量定常边容量网络的指标来度量随机混合容量网络的脆弱性。     

一种电弧炉系统的频域谐波分析方法

提出了一种能分析电弧炉系统分数谐波的频域模型。这个模型假设了一种动态、非线性的电弧u-i特性和一连续变化的电弧电流。经过计算机程序求解可得电弧炉系统的分数谐波。     

具有特殊地形条件的长距离供水工程水锤防护

在长距离供水工程中输水管道一般按地形走势布置。针对一些地形条件特殊的供水工程,本文提出了一种空气罐与出口溢流池联合设置的水锤防护方案,并建立了出口溢流池的数学模型。在空气罐体型一定时,给出了出口溢流池截面积的理论计算公式,有效地减小了在溢流池体型初期选取过程中的盲目性和工作量。结合某长距离输水工程,对比分析了空气罐和出口溢流池联合防护与单纯的空气罐防护对水锤的影响。结果表明空气罐与出口溢流池联合防护方案在前陡后缓的长距离供水工程中能够取得良好的水锤防护效果,且溢流池的溢流水位越高,其对负压的防护效果越好。     

A Fixed-frequency Series-parallel Resonant Converter with Capacitive Output Filter: Analysis,Design, Simulation,and Experimental Results

In this article, a fixed-frequency phase-shift-controlled full-bridge series-parallel (or LCC-type) resonant converter that uses a capacitive output filter is proposed. Steady-state analysis of this converter is performed by using a complex AC circuit analysis approach. Based on the analysis, a simple design procedure is given and exemplified with a design example of a 200- to 220-V DC input, 300-W, 100-V output converter. The relationship between the design parameters, switch stresses, and converter size is illustrated. Both computer simulation and experimental results on a lab prototype converter are presented to verify the performance of the designed converter for varying input voltage and load conditions. It is shown that this converter requires a narrow variation in pulse width for a wide variation in the load, while the peak current through the switches decreases with the load current. One typical application of this converter is for use as a second stage for AC-to-DC converters.