基于CDC技术电容层析成像系统的研究  

Research of Capacitance Tomography System Based on CDC Technology

作　　者：田海军[1] 陈万喜[1] 孙洪亮[1] 徐晓亮[2] 

机构地区：[1]东北电力大学自动化工程学院,吉林吉林132012 [2]沈阳华晨宝马汽车有限公司,沈阳110000

出　　处：《化工自动化及仪表》2014年第6期647-651,668,共6页Control and Instruments in Chemical Industry

基　　金：国家自然科学基金资助项目(61304015)

摘　　要：针对电容层析系统中的微小电容的检测问题,设计了一套以AD7746为核心芯片的微小电容在线检测装置,该装置是以八电极圆形管道为模型,通过电容数字转换技术(CDC)对微小电容进行检测。与传统的AC电桥测量装置相比,电容检测电路得到简化;与充/放电原理电容检测相比,不存在电荷注入和零点漂移,提高了电容检测系统的稳定性和精确性。同时利用有限元计算了灵敏度,使用线性反投影法(LBP)进行成像,该装置对实际的两相流在线检测具有非常重要的现实意义。Aiming at the small capacitance detection,a AD7746 chip-cored capacitance tomography system was developed,which takes the eight-electrode round tube as a model,and applying CDC technology to detect small capacitance. Compared with the conventional AC bridge measurement device,the capacitance detection circuit is simple; and compared with charge /discharge capacitive sensing principle,no charge injection and zero drift can be found,this improves measurement stability and accuracy; and the finite element algorithm used can benefit the improvement on sensitivity; and the linear back projection can be applied in the image formation. This device has important practical significance on the on-line inspection of two-phase flow.

关 键 词：微小电容 AD7746 CDC 电容传感器 

分 类 号：TH878.1[机械工程—仪器科学与技术]