作者：钱承1, 李诺2
作者单位：1. 中国合格评定国家认可中心，北京 100062;
2. 辽宁省计量科学研究院，辽宁 沈阳 110004
关键词：微小电流测量;辐射测量设备;地环技术;绝缘技术;相位补偿;噪声抑制;局部放电(pd)
摘要：
为解决辐射测量传感器输出电流难以准确采集的问题，该文设计并实现一种pa级电流放大器。首先对放大器的低频截止点、高频截止点、噪声特性和漂移等关键指标进行分析，基于电容积分原理设计一种用于pa级电流采集的电荷放大器，并从施加等电位屏蔽、提高绝缘性能、应用相位补偿和抑制噪声四个方面对放大器的性能进行优化，以确保其输出稳定可靠。最后，在多功能校准源fluke 5720a、标准分压器和标准电阻箱辅助下，将该放大器的输出结果与keithley 6514的测量结果进行比较，确定该放大器的测量准确度优于1%。并对该放大器的改进方向进行阐述。该放大器已被用于局部放电量在10 pc及其以下的校正脉冲发生器校准中，并取得良好的效果。
design of charge integration amplifying circuit for radiation-measuring
qian cheng1, li nuo2
1. china national accreditation service for conformity assessment, beijing 100062, china;
2. electronic institute, liaoning provincial institute of measurement of china, shenyang 110004, china
abstract: in order to solve the micro-current sample problem whose value is less than 1μa, a pa level current amplifier is designed and implemented in this paper. first the basic design principle and its calculation formulas such as low cut-off frequency, high cut-off frequency, noise characters and drift characters are analyzed, and a charge amplifier used for measuring pa level current is designed with capacitor integration method, and then in order to ensure its output is stable and reliable, four aspects such as applying equipotential shielding, enhancing insulation performance, compensating the phase and suppression noise are used for optimizing the performance of the amplifier. finally, with the assistance of fluke 5720a, standard voltage divider and standard resistance box, the results of the amplifier are compared with the measurement results of keithley 6514, and the measurement accuracy of the amplifier is determined to be better than 1%. in the conclusion section, the work of dissertation is summarized and prospect of improving direction of system is presented. at present, the amplifier has been used in calibrating the standard pulse generators whose discharge power is below 10 pc and has achieved good results.
keywords: micro-current measurement;radiation-measuring device;guard ring;insulation;phase compensation;noise suppression;pd
2023, 49(2):139-143 收稿日期: 2022-10-30;收到修改稿日期: 2022-12-13
基金项目: 原辽宁省质量技术监督局科技计划项目（2013606）；辽宁省自然科学基金指导计划项目（2019-zd-0864）
作者简介: 钱承(1987-),男,北京市人,高级工程师,硕士,主要从事计量校准方法与设备研发
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