人工中点在不对称三相三线制正弦电路功率测量中的应用研究

三相电路中总有功功率的测量是学术和工程的重要内容。三相三线制是三相电路的一种形式。人工中点在三相三线制电路功率测量中得到了广泛应用。首先介绍应用人工中点测量三相三线制正弦电路有功功率的基本原理,然后理论分析了人工中点测量电路的测量结果,最后通过计算实例验证理论分析的正确性。结果表明,对于电源和负载均不对称的三相电路,无论负载是星接还是三角接,应用了人工中点的测量电路均能够得到正确的测量结果,不会产生计量误差。     

涡流头检测技术的新应用

阐述了涡流头在现场不揭缸情况下轴系中心恢复方面的应用技术,分析了测量原理和相应计算方法,给出了典型的用于现场的测量配置及其测量电路,最后给出应用实例。     

基于等效电路模型的超声波电动机匹配电路研究

针对超声波电动机LC匹配电路的电压增益易受驱动电压频率和温度影响,从而造成调频调速方式下电机转速控制变量驱动电压频率和幅值发生耦合的问题,对超声波电动机等效静电容温度特性进行测试和计算,基于等效电路模型分析了频率和温度对LC匹配电压增益的影响,对LCC匹配电路和LLCC匹配电路进行计算和分析,提出了一种带反馈回路的LC匹配电路。仿真结果表明,在驱动电压频率和温度变化时,带反馈回路的LC匹配电路输出电压幅值基本恒定,增益可调,且调节速度快、精度较高,实现了超声波电动机转速控制变量解耦。     

150W PT功率变换器输入匹配网络的设计

本文从压电陶瓷变压器（PT）自身的工作特点和电气特性出发,提出PT功率变换器主电路的设计方法——窄带控制方法,并应用该主导思想设计并验证了输入匹配网络。主要完成了如下工作：分析了输入匹配网络的作用,给出了设计方法.并计算出各个参数;根据确定的参数用PSpice进行了仿真,结果显示系统达到设计要求;测量了加入匹配网络后的关键实验波形.波形显示.加入输入匹配网络后,基本满足设计要求。实现了窄带控制.输出功率达到150W.效率达到90%。     

150W PT功率变换器输入匹配网络的设计

本文从PT本身的工作特点和电气特性出发，提出PT功率变换器主电路的设计方法——窄带控制方法，并应用该主导思想设计并验证了输入匹配网络，主要完成了如下工作：⑴分析了输入匹配网络的作用，给出了设计方法，并计算出各个参数；⑵根据确定的参数用Pspice进行了仿真，结果显示系统达到设计的要求；⑶测量了加入匹配网络后的关键实验波形，波形显示，加入输入匹配网络后，基本满足设计要求。实现了窄带控制，输出功率达到150W，效率达到90％。     

晶振电路的原理及匹配方法

本文介绍了单片机系统晶振电路的原理、晶振电路参数的计算和晶振电路的匹配方法,总结了晶振电路的参数调整经验。     

一种新型在线系统阻抗测量方法

针对电网的系统阻抗参数在电力系统应用中的重要作用,提出一种在线实时电网系统阻抗测量方法.该测量方法利用不控整流桥电路在换相时的自然短路过程来测算电网系统阻抗,并根据电网线电压和电流变化率过零时的电路特点,引入过零测算法来计算测量值,使本方法能在线、实时测量单相、三相对称和不对称电网系统.同时为提高测量精度,在分析测量误差的基础上提出提高系统测量精度的改进方案.仿真和实验结果证实了这种测量方法的正确性和实用性.     

空间相机CCD信号处理电路匹配性分析

在应用CCD探测器的空间相机系统中,CCD信号处理电路与CCD探测器的匹配性至关重要,决定了整个相机系统的性能指标,因此在CCD信号处理电路设计完成后,需要对设计的匹配性进行分析。首先,介绍了空间相机系统CCD信号处理电路的典型结构;然后,提出了基于动态范围的匹配性分析方法;最后,应用该分析方法对某空间相机系统的CCD信号处理电路设计进行了匹配性分析,发现了电路设计中存在的不匹配环节,为优化电路设计提供了依据和建议。     

一种基于散射参数的电压互感器二端口高频电路模型

为了计算气体绝缘变电站(GIS)内由特快速暂态过电压(VFTO)对二次设备产生的传导干扰,必须建立电压互感器和电流互感器(PT/CT)的高频模型。为此,该文提出了基于散射参数的互感器二端口高频电路模型建立的新方法。该方法首先将测量得到的互感器的散射参数转化为导纳参数并构建互感器的p形等值电路;然后,应用矢量匹配法对p形等值电路的导纳参数进行有理函数逼近获得它们部分分式和形式的频域表达式;最后采用电路综合方法构建出导纳元件的等值电路。时域仿真和实测结果的比较验证了该方法的可行性和有效性。该方法具有简单、有效和通用的特点,克服了以前建模方法的不足,所建立的模型可以使GIS内的传导干扰计算更为准确。     

电容分压器低压测量电缆的匹配问题

早在1932年F.P.Burch就提出了在电容分压器低压测量电缆的首、末两端进行匹配的线路,并通过计算确定了匹配条件和误差。本文用Bergeron法借助于电子计算机对这个问题进行了大量的计算后发现,匹配的最佳值和Burch的结论不一样;而且对于不同的情况,最佳匹配值亦不是同一数值,应根据具体情况经过计算来确定。本文具体介绍了最佳匹配值的计算方法。     

Suppression of overtone oscillation and low‐current operation using novel‐design scheme for quartz crystal oscillators

A novel design is proposed for a low‐frequency quartz crystal oscillator circuit. Negative resistance in a low‐frequency CMOS‐inverter quartz oscillator was reviewed for the fundamental mode at 32 kHz and the overtone oscillation at 200 kHz. Suppression of the overtone oscillation, appropriate gain, and drive current reduction are realized by adding only three circuit components. Experimental results and an estimate of the absolute value of the negative resistance are presented for the conventional Colpitts circuit and two types of the quartz crystal oscillator circuit. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Four‐segment oscillator circuit for piezoelectric sensing devices

Novel circuit design is proposed for a low‐frequency quartz crystal oscillator circuit that consists of four segments. The characteristics of the negative resistance in a low‐frequency Complementary Metal Oxide Semiconductor (CMOS)‐inverter quartz oscillator were reviewed for the two modes of SC (stress‐compensated) cut mode and the overtone of low‐frequency mode; separation of two modes and suppression of overtone oscillation were demonstrated successfully. Experimental results and an estimate of the absolute value of the negative resistance are presented for the four‐segment oscillator circuit and the conventional Colpitts circuit and two new types of oscillator circuits. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

振荡回路元件参数分析与计算

本文介绍了大容量试验室振荡回路的试验参数计算方法,并在此基础上利用Atp软件模拟了试验成功和试验失败工况下振荡回路各元件承受的耐受电压、耐受电流和热容量,最后以电容器组和电阻器组为例,给出了振荡回路元件参数的确定步骤。分析结果表明,本文所提方法对大容量实验室振荡回路元件参数的确定具有一定的适用性。     

A generalized family of memristor‐based voltage controlled relaxation oscillator

Recently, memristive oscillators are a significant topic in the nonlinear circuit theory where there is a possibility to build relaxation oscillators without existence of reactive elements. In this paper, a family of voltage‐controlled memristor‐based relaxation oscillator including two memristors is presented. The operation of two memristors‐based voltage relaxation oscillator circuits is demonstrated theoretically with the mathematical analysis and with numerical simulations. The generalized expressions for the oscillation frequency and conditions are derived for different cases, where a closed form is introduced for each case. The effect of changing the circuit parameters on the oscillation frequency and conditions is investigated numerically. In addition, the derived equations are verified using several transient PSPICE simulations. The power consumption of each oscillator is obtained numerically and compared with its PSPICE counterpart. Furthermore, controlling the memristive oscillator with a voltage grants the design an extra degree of freedom which increases the design flexibility. The nonlinear exponential model of memristor is employed to prove the oscillation concept. As an application, two examples of voltage‐controlled memristor‐based relaxation oscillator are provided to elaborate the effect of the reference voltage on the output voltage. This voltage‐controlled memristor‐based relaxation oscillator has nano size with storage property that makes it more efficient compared with the conventional one. It would be helpful in many communication applications.     

车载雷达用恒温石英晶体振荡器设计

根据车载雷达的需要，利用AT切石英晶体谐振器从主振电路、辐度放大电路、波形变换电路、自动增益电路和压控电路等诸多因素综合考虑，设计了车载雷达用的小型单层恒温高稳晶振，具有良好的老化特性和高可靠性。     

Short‐term stability in the intermediate region between quartz crystal oscillation and LC oscillation

In a quartz crystal oscillator circuit, an LC resonance circuit was inserted that enabled major enlargement of the variable range of frequency compared with the conventional Colpitts or Pierce quartz crystal oscillator. The short‐term stability of the oscillation was measured with Allan variance in the intermediate region between the quartz resonance and LC resonance, showing higher stability compared with the common LC oscillator. The analytical result is presented showing continuous transition from the quartz resonance to the LC resonance. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于西勒振荡器的高频功率放大电路设计

根据正弦波振荡电路的起振原理,设计了西勒振荡器,作为高频功率放大电路的输入端。利用射极跟随器可连接于两电路中间起缓冲作用的特性,设计了缓冲电路。整个设计末端,用一个丙类谐振功放来进一步增强输出电压和输出功率。采用LTspice软件对设计的高频功率放大电路特性进行模拟仿真与分析,验证了理论分析的正确性与可行性。     

微波Colpitts混沌电路在无线传输系统中的应用

Colpitts混沌振荡电路由单一的晶体三级管及其它线性元器件构成,是研究及应用非常广泛的三点式振荡电路。Colpitts混沌振荡电路能够产生各种不同频率的混沌信号,可以应用于无线传输、通信加密、信号检测等多个领域。介绍了两种类型的Colpitts混沌振荡器电路,并分析了其电路模型。同时将所产生的混沌振荡信号进行了对比、分析,并将其产生的混沌信号作为无线传输系统的激励信号。此外,互补累积分布函数曲线表明,以改进型的Colpitts混沌振荡电路所产生的混沌信号作为激励信号的无线电力传输系统具有更好的整流电路转换效率。最后,这些电路的转换效率的详图已被证明。     

Analyses and techniques for phase noise reduction in CMOS Colpitts oscillator topology

This paper reports the analyses of three techniques for phase noise reduction in the complementary metal‐oxide semiconductor (CMOS) Colpitts oscillator circuit topology. Namely, the three techniques are inductive degeneration, noise filter, and optimum current density. The design of the circuit topology is carried out in 28‐nm bulk CMOS technology. The analytical expression of the oscillation frequency is derived and validated through circuit simulations. Moreover, the theoretical analyses of the three techniques are carried out and verified by means of circuit simulations within a commercial design environment. The results obtained for the inductive degeneration and noise filter show the existence of an optimum inductance for minimum phase noise. The results obtained for the optimum bias current density technique applied to a Colpitts oscillator circuit topology incorporating either inductive degeneration or noise filter show the existence of an optimum bias current density for minimum phase noise. Overall, the analyses show that the adoption of these techniques may lead to a potential phase noise reduction up to 19 dB at a 1‐MHz frequency offset for an oscillation frequency of 10 GHz. © 2015 The Authors International Journal of Circuit Theory and Applications Published by John Wiley & Sons Ltd.     

一种交错并联电路的控制部分设计

本文介绍了UC3846的工作原理，设计了一种采用晶振、反相器、脉冲计数器与UC3846一起产生频率的交错并联控制电路。