暂态行波电流放大器的精度和频率优化  

Accuracy and Frequency Optimization of Transient Traveling Wave Current Amplifier

作　　者：周鹏鹏 王伟 张彦兵 陈朋 ZHOU Pengpeng;WANG Wei;ZHANG Yanbing;CHEN Peng(Xuchang KETOP Testing Research Institute Co.,Ltd.,Xuchang 461000,China)

机构地区：[1]许昌开普检测研究院股份有限公司,河南许昌461000

出　　处：《自动化仪表》2021年第1期29-33,共5页Process Automation Instrumentation

摘　　要：在行波测距装置的研发和校验过程中,稳定、可靠的暂态行波测试仪不可缺少,而暂态行波电流放大器是其重要的一环。针对目前电流功率放大器电路结构的缺点,提出了一种改进的功率运放扩流电路设计方案。使用功率运放直接推动扩流三极管,减少了驱动级数;使用独特的浮地偏置电路,解决了交越失真问题。运用理论分析和实际电路相结合的方法,对放大器的低频精度和高频特性进行了优化,指出影响低频增益的主要因素是反馈电阻的匹配精度和采样电阻的温度系数,影响高频增益特性的主要原因是趋肤效应、导线自电感和功率运放带宽。实际电路验证结果表明,设计的暂态行波电流放大器具有较好的幅值精度和频率特性,能够满足行波测距装置的校验需求。During the development and verification of traveling wave fault location devices,a stable and reliable traveling wave testing platform is indispensable,and the transient traveling wave current amplifier is an important part of it.In view of the shortcomings of the current power amplifier circuit structure,an improved current expanding circuit scheme of the Power Op-Amp is presented.The Op-Amp directly drives the power triode to reduce the drive series,and the unique floating-ground bias circuit overcomes the cross-distortion.The low frequency accuracy and high frequency characteristics of the amplifier are optimized by the combination of theoretical analysis and practical circuit.It is pointed out that the main factors affecting the low frequency gain are the matching accuracy of the feedback resistance and the temperature coefficient of the sampling resistance,and three main reasons affecting the high frequency gain characteristics:skin effect,self-inductance of the conductor and bandwidth of Power Op-Amp.The verification results of the actual circuit show that the amplitude accuracy and frequency characteristics of the designed transient traveling wave current amplifier can meet the verification requirements of the traveling wave fault location device.

关 键 词：行波测距 电流放大器 功率 幅值精度 频率特性 趋肤效应 导线自电感 

分 类 号：TH39[机械工程—机械制造及自动化]