基于PT1000的太阳能光热实验系统温度测试技术研究

Research on Temperature Measurement Technology of Solar Thermal Experimental System Based on PT1000

设计并实现了基于恒流源驱动四线制PT1000的高精度温度测试系统,分析了温度测试系统中恒流源电路、信号调理电路、A/D转换等单元电路的设计依据和工作原理,给出了电路结构和相关参数.系统引入分段线性化算法,采用最小二乘法对实测数据进行线性拟合,并利用误差评估原理对拟合结果进行评估来确定适用于PT1000的最佳校正方程.实验表明,该系统的精度在0~90℃范围内优于±0.1℃,适用于高精度温度测试,相关技术已应用于福建师范大学新能源工程中心的太阳能光热实验教学系统中.

This paper designs and realizes the high-precision temperature measurement system based on PT1000 which is driven by four-wire constant-current source, it analyzes the operation principles and design basis of the functional circuits in this temperature measurement system, which consists of constant-current source, signal processing and A/D conversion, it also gives circuit structures and parameters. The System using piecewise linearization algorithm, using the least square method for linear fitting the measured data, and it also uses the principle of fitting error evaluation to evaluate the results to determine the best correction equation suitable for PT1000. Experiments show that in the temperature measurement range of 0 -90 ℃, the accuracy can be up to ± 0. 1 ℃, which verifies the system can be used for high precision temperature test. The related tech- nology has been applied to solar-thermal experiment teaching system of new energy engineering center of fujian normal university.