400Hz有源功率因数校正系统设计

设计了一种将220V/400 Hz交流输入转化成直流高压输出的交流/直流(AC/DC)功率变换系统.分析了该电路拓扑的工作原理,推导了解耦算法步骤,并对主体电路进行了分析.结果表明该技术具有控制方便、结构简单且功率因数很高的优点,适合中大功率应用场合.     

PWM整流电路的原理分析

无论是不控整流电路,还是相控整流电路,功率因数低都是难以克服的缺点.PWM整流电路是采用PWM控制方式和全控型器件组成的整流电路,本文以《电力电子技术》教材为基础,详细分析了单相电压型桥式PWM整流电路的工作原理和四种工作模式.通过对PWM整流电路进行控制,选择适当的工作模式和工作时间间隔,交流侧的电流可以按规定目标变化,使得能量在交流侧和直流侧实现双向流动,且交流侧电流非常接近正弦波,和交流侧电压同相位,可使变流装置获得较高的功率因数.     

单相电压型PWM整流电路原理分析与仿真

详细分析单相电压型PWM整流电路的工作原理和工作模式,说明通过对PWM电路进行控制,选择合适的工作模式和工作时序,可使PWM整流电路的输出直流电压得到有效的稳定.同时也调节了交流侧电流的大小和相位,实现能量在交流侧和直流侧的双向流动,并使变流装置获得良好的功率因数.最后建立其Matlab的仿真模型,验证了设计的正确性.     

用运算放大器构成理想变压器及其仿真测量

提出了实现理想变压器的一种新方法,从理论上证明了通过运算放大器和电阻元件构成的"理想变压器"满足理想变压器的定义条件。并对运算放大器和电阻元件实现的理想变压器电路在交流、直流以及其它波形的信号源下的工作进行了仿真测量,验证了理想变压器对电压、电流的频率和波形没有任何限制,这一结论证明了理想变压器是既能工作于交流又能工作于直流的理想电路元件,指出了对电路教学具有的意义。     

日立SHAVERES381充电电动剃须刀剖析与故障检修

笔者修理该日产381型剃须刀,其内部结构、原理与其它产品有很大区别。电路比较复杂。日立SHAVERES381电动剃须刀电路原理如附图所示。此电动剃须刀不是直接将交流市电降压整流后对内部充电,而是利用低频振荡电路产生的交流电压经半波整流、滤波后对电池进行充电的。1.电路工作原理当剃须刀接入市电后,由D1、R1、C1组成的半波整流电路开始工作。在电容器C1两端获得100V的脉动直流电压,该     

基于电流源的在线电感值测量电路设计

文章主要讨论基于交流恒流源的电感值的检测方法.首先利用交流电通过变压器和整流电路实现由交流到直流的转换,达到幅值变换,再经过稳压电路实现直流恒压源,之后经过RC振荡电路实现频率和幅度可调的交流恒流源,在RC振荡电路中改变相应的C和R的值来实现所要求的频率可调范围.利用所得的交流恒流源与要在线检测的电感通过测试电路连接起来,最终实现电感的在线精确检测.     

无输入变压器的6 V100 A稳压电源

本文叙述采用脉宽调制技术的开关式电源的工作原理和设计.电路输出600W,且直接输入240V交流而不使用50赫电源变压器.总的效率约为60～65%,几乎与负载无关.可以改进电路,输入其他电压例如50V直流电压.     

模拟电路关键环节OP放大器(上)

Transistor电路的困难点 直流与交流工作必须分开考虑 图1是典型的模拟电路,外观看似简易的Transistor交流放大电路,然而实际上为了解该电路的工作特性,因此必须将决定工作点视为直流工作,该工作点又称为直流偏压(bias).如图1所示,由于collector信号中点(平均值)的直流电流,与无信号时的collector电压相等,所以决定工作点时必须利用图2所示的直流动作电路作检证.     

电源技术讲座 第五讲 晶体管直流变换器

直流变换器通常是指一种直流电压变换装置,其主要功能是转换电压,把直流电压转换成交流电压,或把一种直流电压转换成各种不同的直流电压。所以有人称直流变换器为转换器或换流器,也有专把直流转换成交流的,称作逆变器。本文所讨论的是晶体管直流电压变换器。晶体管直流电压变换器的基本工作原理是,利用晶体管作为断续开关,控制直流电源的接通和断开,再经过变压器输出,把直流变换成交流,然后经过整流成直流。一、单管式直流变换器这里讨论的是单管自激式直流电压变换器,基本电路如图1所示。它是一种反激型电路,其工作原理是,当电源接通后,经电阻 R_1、R_2分压,     

LEM传感器在交错Boost型PFC电路中的应用

为了解决双Boost并联运行的PFC电路中各支路电流、总电感电流、直流侧二极管电流、开关管电流及输入交流电流的检测问题,文中介绍了LEM公司的一种电流传感器.并利用LEM传感器具有测量频率范围宽、反应速度快、准确度和线性度高等特点,给出了其在交错Boost型PFC电路中进行直流、不同频率的交流以及脉动电流电气参数测试的具体方法.     

Analysis of the Noise Characteristics of CMOS Current Conveyors

The definition of the current conveyor is reviewed and a multiple-output second generation current conveyor (CCII) is shown to combine the different generations of current conveyors presently existing. Next, noise sources are introduced, and a general noise model for the current conveyor is described. This model is used for the analysis of selected examples of current conveyor based operational amplifier configurations and the noise performance of these configurations is compared. Finally, the noise model is developed for a CMOS current conveyor implementation, and approaches to an optimization of the noise performance are discussed. It is concluded that a class AB implementation can yield a lower noise output for the same dynamic range than a class A implementation. For both the class A implementation and the class AB implementation it is essential to design low noise current mirrors and current sources, and with the class AB design, the current mirror and current source noise can be reduced by using small values of bias current without compromising the maximum available output current.     

Compensation-based nonactive power definition

This paper presents a new definition of nonactive current from which the definitions of instantaneous active and nonactive power are also derived. The definitions are consistent with the traditional power definitions and valid for single-phase and polyphase systems, as well as periodic and nonperiodic waveforms. The definitions are applied to a shunt compensation system. The paper elaborates on the compensation of three different cases of nonperiodic current: single-phase disturbance, three-phase subharmonics, and three-phase stochastic current. Simulation results give credibility to the applicability of the definition for a diversity of load currents. According to different compensation cases and the goals to be achieved, different averaging time intervals for the compensator are chosen which will determine the compensator's energy storage requirement and the extent of residual distortion in the source current.     

新型电流控制电流传输器

提出了一种新型电流控制电流传输器(CCCII)电路。该CCCII电路由跨导线性环电路和双极性Wilson电流镜构成。为实现该新型CCCII电路,还提出了双端输出的双极型Wilson电流镜。该CCCII电路具有输出阻抗高、电压及电流传输精度高、易于实现、便于集成等优点。文中分析了电路的工作原理,给出了实验结果,验证了电路的正确性。     

基于电流分解的单相无功功率定义及测量方法

周期非正弦激励电路中的无功功率定义是一个颇具争议的问题。本文提出了一种基于Fryze时域电流分解的单相无功功率定义方法,给出了这种定义下正弦激励下各种线性元件和非线性元件的无功功率表达式,以及非直线激励下线性电阻元件的无功功率表达式。推导结果表明,这种无功定义能更加直接地准确定位系统中的谐波源,更加有利于谐波治理和无功的实时补偿,文章最后给出了基于Matlab的电流分解算法,为无功实时补偿和无功电能计量奠定了基础。     

箔条感应电流分布和散射特性研究

推导了箔条雷达散射截面(RCS)的计算公式及其衍生的公式;基于矩量法和伽略金法,计算和比较了箔条散射与振子辐射的感应电流分布和远场方向图的差异,讨论了箔条空中姿态对感应电流分布及远场方向图的影响;给出了单站散射和双站散射情形单根箔条平均有效雷达截面的定义和计算公式.     

电流阀值对断续骚扰检测结果的影响

对于某些由开关操作数得出喀呖声率的被测设备,目前大部分检测实验室的断续骚扰分析仪可能会漏计算一些开关操作。解释了标准中"开关操作"的定义,通过实际案例阐述了使用分析仪进行断续骚扰项目检测时,预置电流阀值的选择对检测结果的影响。     

基于复合管改进型电流镜的CCCⅡ电路

提出了一种新型的电流控制第二代电流传输器电路。该电路由6个复合管改进型电流镜和1个跨导线性环组成,该电路的电流传输精度远高于基于基本电流镜和级联电流镜实现的电流控制第二代电流传输器(CCCII)的电流传输精度。对电路原理进行了分析,并进行了硬件实验,实验结果表明频率在0～1.3MHz范围内能很好地满足CCCII的电流和电压特性关系,从而证明提出的电路是正确的。     

基于复合管改进型电流镜的CCCII电路

提出了一种新型的电流控制第二代电流传输器电路。该电路由6个复合营改进型电流镜和1个跨导线性环组成．该电路的电流传输精度远高于基于基本电流镜和级联电流镜实现的电流控制第二代电流传输器（CCCII）的电流传输精度。对电路原理进行了分析，并进行了硬件实验，实验结果表明频率在0-1．3MHz范围内能很好地满足CCCII的电流和电压特性关系，从而证明提出的电路是正确的。     

Fault Detection in Switched Current Circuits Using Built-in Transient Current Sensors

Switched current (SI) circuits use analogue memory cells as building blocks. In these cells, like in most analogue circuits, there are hard-to-detect faults with conventional test methods. A test approach based on a built-in dynamic current sensor (BIDCS), whose detection method weights the highest frequency components of the dynamic supply current of the circuit under test, makes possible the detection of these faults, taking into account the changes in the slope of the dynamic supply current induced by the fault. A study of the influence of these faults in neighbouring cells helps to minimize the number of BICS needed in SI circuits as is shown in two algorithmic analogue-to-digital converters. Yolanda Lechuga received a degree in Industrial Engineering from the University of Cantabria (Spain) in April 2000. Since then, she has been collaborating with the Microelectronics Engineering Group at the University of Cantabria, in the Electronics Technology, Systems and Automation Engineering Department. Since October 2000 she has been a post-graduate student, to be appointed as lecturer at this university, where she is working in her Ph.D. She is interested in supply current test methods, fault simulation, BIST and design for test of mixed signal integrated circuits. Román Mozuelos received a degree in Physics with electronics from the University of Cantabria, Spain. From 1991 to 1995 he was working on the development of quartz crystal oscillators. Currently, he is a Ph.D. student and an assistant teacher at the University of Cantabria in the Department of Electronics Technology. His interests include mixed-signal design and test, fault simulation, and supply current monitoring. Miguel A. Allende received his graduate degree in 1985 and Ph.D. degree in 1994, both from the University of Cantabria, Santander, Spain. In 1996, he became an Assistant Professor of Electronics Technology at the same Institution, where he is a member of the Microelectronics Engineering Group at the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. His research interests include design of VLSI circuits for industrial applications, test and DfT in digital VLSI communication circuits, and power supply current test of mixed, analogue and digital circuits. Mar Martínez received her graduate degree and Ph.D. from the University of Cantabria (Spain) in 1986 and 1990. She has been Assistant Professor of Electronic Technology at the University of Cantabria (Spain) since 1991. At present, she is a member of the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. She has participated in several EU and Spanish National Research Projects. Her main research interest is mixed, analogue and digital circuit testing, using techniques based on supply current monitoring. She is also interested in test and design for test in digital VLSI circuits. Salvador Bracho obtained his graduate degree and Ph.D. from the University of Seville (Spain) in 1967 and 1970. He was appointed Professor of Electronic Technology at the University of Cantabria (Spain) in 1973, where, at present, he is a member of the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. He has participated, as leader of the Microelectronics Engineering Group at the University of Cantabria, in more than twenty EU and Spanish National Research Projects. His primary research interest is in the area of test and design for test, such as full scan, partial scan or self-test techniques in digital VLSI communication circuits. He is also interested in mixed-signal, analogue and digital test, using methods based on power supply current monitoring. Another research interest is the design of analogue and digital VLSI circuits for industrial applications. Prof. Bracho is a member of the Institute of Electrical and Electronic Engineers.     

几种非侵入式电流测量技术

电流测量是工业生产和科学研究中经常进行的项目.与传统的欧姆定律方法相比,非侵入式电流测量技术具有与被测电路电隔离、精度高、易于实现自动化等优点,具有广阔的应用前景.在调查非侵入式电流测量技术应用现状的基础上,总结了目前常用的几种测量方法的原理,包括电流互感器、Rogowski线圈、霍尔电流传感器、光学电流传感器、磁阻电流传感器等,介绍了各自的特点,并对电流传感器的发展趋势做了展望.