从UPS电路拓扑看在线式UPS的性能优势

本文介绍分析了后备式、在线互动式和在线双变换式等各类UPS电路拓扑与性能，指出在线或UPS性能优势所在。     

Practical Control Implementation of a Three- to Single-Phase Online UPS

A high-performance three- to single-phase online uninterruptible power supply (UPS) is proposed. The proposed UPS is composed of a rectifier, a battery charger/discharger, and an inverter. The rectifier has the capability of power-factor correction and regulates a dc-link voltage. When the rectifier becomes unavailable or when the current required by the load exceeds the output rating of the rectifier, the charger/discharger supplies the power demanded by the load to a dc-link capacitor. The inverter provides a regulated sinusoidal output voltage and limits an output current under an impulsive load. New control algorithms of the rectifier, the charger/discharger, and the inverter are proposed. The proposed algorithms of the rectifier and the charger/discharger improve dynamic performance at step load change. To improve the transient response of the output voltage at outage of an input source, a mode change method of the charger/discharger is also proposed. Additionally, the proposed current-limit algorithm of the inverter can be implemented without additional hardware, and it increases the reliability of the UPS.      

基于DSP控制的在线式UPS装置研究

介绍了一种基于Ti（Texas Instruments）公司的TMS320F240数字信号处理器的在线式UPS，分析了系统设计中的一些关键技术问题。设计了一台容量为6kW的在线式UPS试验装置，并进行了验证，实践证明所研制的装置完全达到技术要求。     

Transformerless Single-Phase Multilevel-Based Photovoltaic Inverter

The elimination of the output transformer from grid- connected photovoltaic (PV) systems not only reduces the cost, size, and weight of the conversion stage but also increases the system overall efficiency. However, if the transformer is removed, the galvanic isolation between the PV generator and the grid is lost. This may cause safety hazards in the event of ground faults. In addition, the circulation of leakage currents (common-mode currents) through the stray capacitance between the PV array and the ground would be enabled. Furthermore, when no transformer is used, the inverter could inject direct current (dc) to the grid, causing the saturation of the transformers along the distribution network. While safety requirements in transformerless systems can be met by means of external elements, leakage currents and the injection of dc into the grid must be guaranteed topologically or by the inverter's control system. This paper proposes a new high-efficiency topology for transformerless systems, which does not generate common-mode currents and topologically guarantees that no dc is injected into the grid. The proposed topology has been verified in a 5-kW prototype with satisfactory results.     

Design of Transformerless Modulator-Demodulator

A transformerless modulator-demodulator that operates over a wide range of frequencies is described. The circuit is designed to exhibit symmetrical full wave rectification, to eliminate offset voltages at the output, and to lack the necessity of being fed from a voltage source. The equations to achieve these features are developed. To satisfy all these equations certain relations between various components must be observed. The solutions of these, obtained by a computer, are given for typical gains.     

Transformerless DC-to-DC converters with large conversion ratios

A novel switching DC-to-DC converter is introduced in which large voltage step-down ratios can be achieved without a very small duty ratio and without a transformer. The circuit is an extension of the Cuk converter to incorporate a multistage capacitor divider. A particularly suitable application would be a 50 V to 5 V converter in which DC isolation is not required. The absence of a transformer and a larger duty ratio permits operation at a high switching frequency and makes the circuit amenable to partial integration and hybrid construction techniques. An experimental 50 W three-stage voltage divider Cuk converter converts 50 V to 5 V at 500 kHz, with an efficiency higher than that for a basic Cuk converter operated at the same conditions. A corresponding voltage-multiplier Cuk converter is described, as well as dual buck-boost-derived step-down and step-up converters     

单相高效无变压器式光伏逆变器的设计理念

效率已经成为衡量光伏逆变器最重要的一个指标。本文针对单相小功率光伏逆变器应用,详细介绍了改善光伏逆变器效率的方法,并结合Vincotech公司最新推出的功率模块(FZ06BIA045FH-P897E)给出了具体应用和仿真结果。     

UPS漫谈

可能很多人都有这样一个错误的概念，认为我们使用的市电，除了偶尔发生的断电事故外，是连续而且恒定的，其实不然。市电系统作为公共电网，上面连接了成千上万各种各样的负载，其中一些较大的感性、容性、开关电源等负载不仅从电网中获得电能，还会反过来对电网本身造成影响，恶化电网或局部电网的供电品质，造成市电电压波形畸变或频率漂移。另外意外的自然和人为事故，如地震、雷击、输变电系统断路或短路，都会危害电力的正常供应，从而影响负载的正常工作。根据电力专家的测试，电网中经常发生并且对电脑和精密仪器产生干扰或破坏的问…     

浅谈UPS

1UPS概述 随着计算机技术的高速发展,计算机控制技术广泛应用于各个行业中.     

UPS系统技术和Delta变换UPS系统

阐述国内外UPS系统技术现状和发展趋势,讨论传统的双变换在线UPS系统存在的问题及解决办法,介绍单变换UPS系统,最后着重介绍Delta变换UPS系统。     

浅谈UPS

随着计算机技术的日益普及和应用，信息和数据的存储显得越来越重要，由于电力的突然中断，造成信息的丢失，以及电力质量差（如突波、电压的过高或过低等）给企业和个人造成损失。ＵＰＳ的出现使得这些问题得以解决。那么什么是ＵＰＳ？ＵＰＳ又是基于什么原理工作的呢？ＵＰＳ的发展历程 ＵＰＳ是不间断电源（Ｕｎｉｎｔｅｒｒｕｐｔｉｂｌｅ ＰｏｗｅｒＳｙｓｔｅｍ）的英文缩写，是一种含有储能装置，以逆变器为主要部分的恒压恒频的不间断电源。现在ＵＰＳ已经被广泛应用于计算机、交通、银行、证券、通信、医疗、工业控制等行业，并且…     

浅说UPS

<正> UPS的功能与作用 UPS是不间断电源(Uninterruptible Power System)的英文名称的缩写,它伴随着计算机的诞生而出现,是计算机常用的外围设备之一。实际上,UPS是一种含有储能装置,并以逆变器为主要组成部分的恒压恒频的不间断电源, UPS在其发展初期,仅被视为一种备用电源。后来,由于电压浪涌、电压尖峰、电压瞬变、电压跌落、持续过压或者欠压甚至电压中断等电网质量问题,使计算机等设备的电子系统受到干扰,造成敏感元件受损、信息丢失、磁盘程序被冲掉等严重后果,引起巨大的经济损失。因此,UPS日益受到重视,并逐渐发展成一种具备稳压、稳频、滤波、抗电磁和射频干扰、防电压浪涌等功能的电力保护系统。目前在市场上可以购买到种     

产生双极性输出的无变压器DC／DC变换器

要从单个正极性输入产生双极性(正和负)输出的常见方法是采用变压器.虽然这种设计比较简单,但变压器本身会带来体积问题.把一个变压器装入一台要求减小电路占用面积和高度的设备中,这是具有挑战性的.图1所示电路可以从由3V～10V输入产生±5V输出,适用于没有地方安装变压器的设备.该电路所用的一种结构,能在DC/DC变换器处于关机模式时切断两个输出,这样就使处于关机(待机)模式时的静态电流很小.     

UPS and downs

The latest annual report on distribution and transmission system performance from the Office of Electricity Regulation presents a reasonably cheerful picture to the electricity consumer in general. But it also throws into sharper focus the risks that businesses run if they fail to provide uninterruptible power support for their computer installations. The author describes how, nevertheless, many companies still run that risk. Many computer systems are more vulnerable to power-related problems now than ever before. If ever there was a time for companies to look at their power back-up strategy, it is now     

UPS的选购

浪涌、欠压、尖峰、掉电……您可能对这些强烈的字眼并不熟悉，可是我敢说，这些现象您可能天天都会碰上——日光灯瞬间的一眨眼，不远处的一个闪电，保险丝突然被烧断，还有其他种种因事故或人为造成的意外……，这样的结果可能使你辛辛苦苦打好的文件或调好的程序一下子全丢掉、可能使你的键盘锁死、硬盘分区表大乱（简直和CIH一样厉害嘛）、甚至可能导致你公司整个网络系统的瘫痪。可怕的是，像轻微的浪涌和欠压这样的问题是无法看到的，但却会悄悄磨损您的设备，让您早晚为此付出代价。有调查表明，一台普通计算机每月所受的电源干扰…     

UPS市场近况

今年上半年是我国UPS市场竞争格局开始形成的一年，是整体UPS市场由成长期向成熟期过渡的一年。过去的这6个月当中，各UPS厂家在经历了不同的酸甜苦辣之后，最终的付出终于得到了各自的回报，但付出与回报二者之间的关系未必成正比，关键还得看厂家的市场行为是否适应市场规律。今年上半年UPS市场的另外一个特点就是不断涌现出新品牌和新面孔。科尔茂、三菱、COMPAQ、华为等厂商的纷纷介入，使得原本竞争已经非常激烈的市场更趋白热化，但从另一个角度也不难看出中国UPS市场潜力之巨大。介入归介入，市场永远都是公平地向每个厂家…     

Transformerless series sag compensation with a cascaded multilevel inverter

The use of a cascaded multilevel inverter for transformerless sag/dip compensation is investigated. This topology is investigated as a cost-effective means for series sag compensation by eliminating the large injection transformer and output filter components that are used in conventional series injection devices. This prototype inverter is designed for sag compensation of a 250-kVA load. In this design, cost effectiveness plays a major role in the selection of the energy storage and the switching components. Control schemes are discussed for series sag compensation with this multilevel inverter. New control methods for sag compensation and injection are also introduced. A prototype is developed and the control schemes of this sag compensator are successfully verified in the practical results and show successful compensation for sags for different types of loads. The performance of this compensator makes it promising for future power rating upgrade and industrialization.     

Transformerless r.p. immittance synthesis from real-part specification

A method is proposed for synthetising transformerless r.p. immittance for the case in which only their real part on the imaginary axis is of interest. The method presents the advantage of requiring a very low number of components and very simple computations.     

无变压器型混合有源滤波器及其控制策略研究

在对一种无变压器型混合有源滤波器的电路拓扑和参数设计方法进行分析研究的基础上,提出一种采用电网谐波电流作反馈控制与负载谐波电流作前馈控制的复合控制策略,并用SIMULINK建立仿真模型进行仿真分析。通过与仅采用电网谐波电流作反馈控制时的仿真结果进行比较,可以看出使用这种复合控制方法,能更有效地抵消电网中的谐波电流,降低总的谐波畸变率。     

UPS蓄电池的选择

蓄电池是UPS系统中的一个重要组成部分。因此，UPS电池的选择不仅关系到经济成本问题、还直接影响UPS电源的不间断供电。根据UPS电池的特点，从电池类型、容量计算、配置方式、寿命及品牌等五个方面分析了如何选择满足负载需要的既经济又可靠的UPS电池，对通信系统长效型UPS电池的选择具有一定的借鉴意义。