一种基于热电偶CJC测温电路的设计  

Research and Design of the Thermocouple CJC Based Temperature Measurement Circuit

作　　者：王冰[1] 任勇峰[1,2] 贾兴中[1] 刘兴俊[1] 

机构地区：[1]中北大学电子测试技术国家重点实验室,太原030051 [2]中北大学仪器科学与动态测试教育部重点实验室,太原030051

出　　处：《电子器件》2016年第4期907-912,共6页Chinese Journal of Electron Devices

基　　金：国家自然科学基金项目(51275491)

摘　　要：针对太空飞船大底区实时环温监测的特殊要求及常见温度传感器存在测试精度低,稳定性差等问题,设计了基于热电偶测温原理的自动CJC电路方案。详细介绍了自动冷端（基准结）补偿式测温电路的设计思路,对于热电偶本身的测量的非线性特性采用分段线性拟合校正算法,并对线性算法处理后的温度的非线性度和高低温误差精度通过了实验验证,符合设计要求。而在太空飞船大底区温度测量环境属于强RFI（射频干扰）环境,极易导致电路中仪表放大器内部射频整流,从而导致输出电压失调。为此,在电路输入前端专门设计了RFI低通滤波器,滤除高频射频信号。基于热电偶CJC测温电路已成功应用于工程实践中,测温范围-60℃~1 300℃,测量精度优于1℃。基于热电偶CJC（冷端补偿）测温电路为温度的精密测量提供了一种快速、有效、精确的手段。On the special requirements for real-time spaceship outsole area monitoring ambient temperature and the presence of common temperature sensor＇ s low precision, poor stability, an automatic CJC circuit scheme was designed based on the principle of the thermocouple. Details of the automatic cold junction （reference junction） temperature compensation circuit design ideas are introduced, and the non-linear characteristics of the thermocouple itself measurement are achieved by using the piecesise linear fitting correction algorithm. The temperature processing with the piecewise linear fitting correction algorithm exhibits an extreme precision in its noninear property, and the errors in its high and low temperaline range meet the design requirement from the experimental verification. In the spaceship outsole zone, temperature measurement environment is a strong RFI （Radio Frequency Interference） environment, it can easily lead to internal RF instrumentation amplifier circuit rectifier, causing the output voltage offset. In the front input end of the circuit an RFI low-pass filter was specially designed to filter out high frequency RF signals. Based on CJC thermocouple temperature measurement circuit has been successfully applied to engineering practice, temperature measurement range -60 ℃-1 300 ℃, the measurement accuracy better than 1 ℃. On thermocouple CJC （cold junction compensation）the temperature measurement circuit provides a fast, efficient and accurate method for precise temperature measurement.

关 键 词：热电偶 冷端补偿 射频干扰 测温电路 

分 类 号：TP212.1[自动化与计算机技术—检测技术与自动化装置]