铂电阻测温的非线性补偿算法分析

Nonlinearity compensation algorithm analysis of platinum resistor for temperature measurement

针对铂电阻测温时存在的本质非线性特征,分析了产生非线性误差的主要原因,阐明了反向分度函数法、牛顿迭代法、查表法等几种主要铂电阻非线性补偿算法的原理与特点,并利用基于单片机的温度测控系统的实测数据作为样本,在Matlab仿真环境下,按不同的曲线拟合阶次和方式等条件,对这些算法的补偿误差进行了对比分析。结果表明:采用分段最小二乘曲线拟合法既简单又能有效地减少补偿误差;在相同条件下,牛顿迭代法的补偿精度高于反向分度函数法和查表法。

Main reasons why nonlinear errors exist in the process of temperature measurements with platinum resistors are analyzed in accordance with the intrinsic nonlinear characteristic of platinum resistors. The principle of several nonlinear compensation algorithms, such as reverse sealing function, Newton iteration method, look-uptable method are introduced. Measuring data based on single-chip temperature measurement and control system are used as samples, and the compensation error of these algorithms is analyzed and compared with the help of MATLAB under the condition of the different curve fitting order and strategy. The results show that sub-leastsquares method which is used to fit the curve of voltage varying with temperature is simple and can reduce the compensation error validly. Meanwhile, the compensation accuracy of Newton iteration method is superior to reverse scaling function and look-up-table method.