圆坯结晶器温度测量数据分析及滤波方法研究

【作者】 张艳；

【导师】 王金城；

【作者基本信息】 大连理工大学 ， 控制理论与控制工程， 2003， 硕士

【摘要】 在连铸生产中，准确、可靠的检测结晶器的温度是十分重要的。由于测温热电偶安装在电磁搅拌(EMS)的交变磁场中，致使检测到的温度信号受到强烈的干扰，因此必须对温度信号进行数字滤波处理，以消除EMS对温度测量的影响。 本文使用Welch法对温度信号进行功率谱估计，得到检测温度信号中的实际温度信号和干扰信号的频率特性，并据此制定出设计滤波器的性能指标。由于普通滤波方法对检测温度的滤波效果不理想，本文采用具有严格线性相位特性的有限冲激响应(FIR)低通数字滤波器对检测温度进行处理。应用MATLAB语言对几种FIR数字滤波器设计方法的仿真研究表明，在满足给定性能指标条件下用切比雪夫等波纹逼近法设计的滤波器是最优的。 应用仿真研究得到的切比雪夫滤波器对在不同的EMS电流和频率等条件下检测到的温度数据进行滤波处理，结果表明，该滤波器计算速度快，具有较窄的过渡带，取得了满意的抗EMS干扰效果。更多还原

【Abstract】 It’s very important of accurate, reliable on-line temperature measurement of the mold during the continuous casting manufacture. It is because the thermocouples are installed in alternating magnetic field of the electromagnetic stirring (EMS) that measured temperature has been gotten strong interference; therefore it’s necessary to filter the influence of EMS.The improved direct method-Welch method used in this paper to estimate the power spectral of measured temperature, and the frequency characteristics of the actual temperature and interference signal in measured temperature are taken, forth more institutes the design performance characteristic of filter. Because the filter effects with filter methods for the measured temperature are unsatisfied, this paper adopts the low-pass finite impulse response (FIR) digital filter with linear phase to deal with measured temperature. MATLAB has been used to simulate and study several FIR digital filter design methods, the results show that the filter designed with Chebyshev equripple approximation is the optimal under the given performance characteristic.The Chebyshev filter has been used to filter measured temperature in different EMS current and frequency conditions, the result indicates that the filter has fast computation speed and narrow transition band. Satisfied effect of EMS interference rejection has proved.更多还原