Optimal power flow with FACTS devices by hybrid TS/SA approach

In this paper, a hybrid tabu search and simulated annealing (TS/SA) approach is proposed to minimize the generator fuel cost in optimal power flow (OPF) control with flexible AC transmission systems (FACTS) devices. The problem is decomposed into the optimal setting of FACTS parameters subproblem that is searched by the hybrid TS/SA approach and the OPF with fixed FACTS parameters subproblem that is solved by the quadratic programming (QP). Two types of FACTS devices are used: thyristor-controlled series capacitor (TCSC) and thyristor-controlled phase shifting (TCPS). Test results on the modified IEEE 30 bus system indicates that the proposed hybrid TS/SA approach can obtain better solutions and require less CPU times than genetic algorithm (GA), SA, or TS alone.     

Stochastic economic analysis of FACTS devices on contingent transmission networks using hybrid biogeography-based optimization

Electrical Engineering - Flexible AC transmission systems (FACTS) devices have advantages of enhancing AC system controllability and stability, increasing power transfer capability and relieving...     

构网型和跟网型电力电子装备混联系统惯量响应的匹配问题综述

构网型和跟网型电力电子装备具有异质化调频特性,导致2类装备交直流混联系统惯量响应阶段的动态交互作用机理复杂,传统的惯量参数匹配原则难以优化系统频率响应的问题。阐述了电力电子装备系统的惯量响应匹配问题,并对现有电压源型变流器的调频控制方法进行了概述。从功频响应分析方法、调频功率分配原则和频率响应特性3个方面对电力电子装备系统惯量配置问题的研究现状展开梳理。对电力电子装备混联系统的统一建模及惯量响应匹配问题提出了研究思路,旨在通过惯量支撑功率的匹配控制提升低惯量电力系统的频率稳定性,从系统层面为高比例电力电子装备友好并网提供基础理论和关键技术支撑。     

Electro-explosive devices

Explosives are an integrated part of our technical infrastructure. They do not need to be used in large quantities to produce their desired effects. Explosives can be applied in small quantities to produce useful mechanical or chemical stimuli. To use an explosive in an application, the explosive needs some form of external stimulation. This stimulation can come in the form of a mechanical force, heat energy or an electrical signal. In this article, we will examine devices that are initiated by electrical stimulus-electro-explosive devices (EEDs). The author begins by considering what EEDs are and the various types of them. He goes on to discuss initiation mechanisms     

Thyristor-controlled phase-shifting devices

Phase-shifting devices with thyristor regulation intended for the constant control of power overflows in power-supply networks with parametric and regime nonuniformity have been developed. The phase shift of the output voltage is regulated using a high-voltage thyristor key, which ensures the speed of the device. Various methods of regulation and corresponding circuits of phase-shifting devices are considered.     

Negative resistance devices

Two-terminal devices which exhibit a type-S (current-controlled) or type-N (voltage-controlled) negative differential resistance can be built using only two bipolar transistors and linear positive resistors without any internal biasing power supply. Two general algorithms are presented in this paper for systematically generating all such devices. Hundreds of negative resistance devices have been derived to date using these algorithms and a selection of these circuits is presented in this paper along with their computer-simulated v-i curves. Laboratory measurements of a few sample circuits agree remarkably well with the computer-simulated results.     

Semiconductor quantum devices

The operation of devices with small enough dimensions for electrons to exhibit wavelike behavior is explained. Two types of device are examined: vertical quantum devices, which include the resonant tunneling structure and the single-electron transistor, and lateral, which include the quantum interference transistor and the spin precession device. The advantages and drawbacks of the two types are identified     

Agile microwave devices

After years of material optimization and laboratory demonstrations of devices, the application of ferroelectrics in microwave technology is gaining momentum. At present, ferroelectric films are used in passive and agile microwave devices and systems including: · parallel-plate and coplanar-plate varactors · tunable resonators, filters, and matching networks · phase shifters and delay lines · ferroelectric-based frequency converters and harmonic generators · voltage-controlled oscillators (VCOs) and amplifiers using ferroelectric varactors · steerable beam antennas and phased arrays · tunable, frequency selective, and impedance surfaces · tunable thin-film bulk acoustic wave resonators (TFBARs) and filters · high-density decoupling capacitors and field dielectrics in CMOS devices. The current status of agile microwave technology is partly summarized in a book chapter [1] and a book [2]. The latter also gives a detailed review of applications of ferroelectrics in microwave technology and a forecast of possible future developments in the field. Several companies have started commercial development and marketing of ferroelectric varactors and devices based on them [3]-[6]. This article highlights the advantages of ferroelectric varactors and gives a few examples of devices and system-level commercialization strategies.     

Microwave medical devices

This article describes several new microwave medical devices that either were or are being developed at MMTC, Inc. in cooperation with the following institutions: Celsion Corporation, Columbia, Maryland (microwave balloon catheters); Montefiore Medical Center (MMC), Bronx, New York (microwave balloon catheters, dual microwave antennas, and microwave poration); and the University of California at San Francisco (conformal array antennas). The individuals who developed these devices have previously published patents and articles that contain most of the material presented here. All of the medical devices described depend on the ability of microwaves to deeply penetrate into living tissues. The depth to which microwaves can penetrate tissues is primarily a function of the dielectric properties of the tissues and of the frequency of the microwaves. In general, the lower the water content of the tissue, the deeper a wave at a given frequency can penetrate. Also, at the frequencies of interest, the lower the frequency, the deeper is the depth of penetration into tissues with given water content     

History of implantable devices

The history of biomedical implantable devices is traced from its beginning in the late 1950s to its status today. The role of industry in making this development possible is highlighted. Special emphasis is placed on the early history of the implantable cardiac pacemaker, the first implantable, electronic biomedical device. Implantable drug delivery systems and the implantable defibrillator are also discussed. Implantable devices of the future are briefly described.     

Reliability of asic devices

Abstract

The use of application-specific integrated circuits (ASICs) has become widespread; from use in sophisticated telecommunications equipment through to children's toys. However, aspects of design, fabrication and testing may not be as rigorous as for the standard components that they are replacing.

ASICs by their nature are usually low volume components and tend to be fabricated using the latest technology. However, the additional substantial costs involved with comprehensive reliability and quality assessment mean that testing is often less exhaustive, resulting in a product of uncertain reliability. Conventional wisdom states that fewer components will mean greater reliability; however if the devices are replaced by one of uncertain reliability, this will not necessarily be the case.

This paper presents some considerations that should to be taken into account when contemplating the use of ASICs in place of conventional components. These are highlighted with specific examples seen at Telecom Australia Research Laboratories (TRL).     

Simulating circuits and devices

The successful engineering realization of high-frequency components and systems for these applications is heavily dependent on computer-aided design (CAD) in numerous respects. There are many different types and levels of modeling and simulation that may be involved, but the following discussion focuses on device modeling and circuit simulation, while also trying to place these within the wider high-frequency, computer-based design context, where possible. Furthermore, much of modern high-frequency design is driven by monolithic microwave integrated circuit (MMIC) technology and the greater levels of integration made possible using this technology. Accordingly, in this short overview of microwave device modeling and circuit simulation, we restrict our attention primarily to MMIC-based design.     

混合动力汽车复合电源的设计

在运用混合动力汽车(HEV)电池和超级电容(UCs)的基础上,设计了一种新型的超级电容-蓄电池复合电源的HEV控制系统(包括一个DC-DC转换器)。在高功率需要时,UC通过DC-DC与电机相连。实验结果表明,该复合电源电动车能兼顾蓄电池和超级电容的优点,可以更好地满足电动车启动和加速性能的要求,并能提高电动车制动能量回收的效率,增加续驶里程,降低了起动污染物的排放,提高了燃油的经济性。     

混合级联多电平逆变器的改进混合调制技术

针对于Ⅲ型混合级联型多电平逆变器调制中,逆变器输出的相电压及线电压包含低频次谐波,以及大调制度下出现的超调问题,提出了一种改进的混合调制策略。该策略通过调制波和一对三角载对高压单元进行调制,得到高压单元输出的PWM波,再利用调制波与高压单元输出的PWM波的差值作为低压单元的调制波对低压单元进行调制,得到低压单元输出的PWM波。仿真与实验结果表明该策略能够消除Ⅲ逆变器输出相电压及线电压中的5次和7次低频谐波和超调现象,逆变器输出的相电压和线电压的总谐波失真(total harmonic elimination,THD)分别为14.53%和12.47%,频谱含量主要分布在2mf两侧。     

BioMEMS devices for drug delivery

Successful therapeutic outcomes following the administration of drugs, including small molecules and large biomolecules, require not only the selection of a proper drug but also its delivery to the proper site of action, with proper temporal presentation. Drug delivery is an extremely broad area of research, as each molecule presents its own absorption, distribution, metabolism, excretion, and toxicology (ADMET) profile. Moreover, timing of drug release may affect the efficacy of a pharmacologic agent. Any means by which drug delivery can be actuated and controlled is, therefore, of interest, and there should be no surprise that microelectromechanical systems (MEMS) have received considerable attention over the past decade in the drug delivery field. The ability to generate two-dimensional (2-D) and three-dimensional (3-D) material constructs accurately and reproducibly using MEMS may lead to substantial advances over conventional drug delivery systems.     

Polymer thermosetting organic light-emitting devices

We report a systematic study of novel single- and double-layer thermosetting light-emitting devices (LED's) based on triarytamines for hole transport layer and fluorenes for the emitting and electron transport layer. These devices possess high-thermal stability, high-quantum efficiency, and high-bandgap emission (blue and green). We have fabricated dot matrix displays based on analogs of these materials     

Early development of defibrillation devices

The recognition of ventricular fibrillation and the development of defibrillation devices are recounted, and recent advances are described. Early experiences with and studies of cardiac arrest are discussed. Transthoracic defibrillation, which was first applied successfully in 1947, is reviewed, and significant research is summarized. The development and present state of the implanted defibrillator, which was suggested in the late 1960s, are examined.