基于双通道检测技术的非分光红外CO_(2)传感器设计与研究

Design and Research of Non-dispersive Infrared CO_(2)Sensor Based on Dual-channel Detection Technology

针对传统红外气体传感器气室与信号处理模块分离存在体积大、灵敏度差的问题,基于非分光红外双通道检测技术,设计了一种小体积、高精度的红外CO_(2)传感器。首先,对反射型气室进行光线追迹仿真,保证热释电探测器受到的红外辐射和气体吸收光路长度满足要求。同时,设计了可靠的光源驱动电路、带通放大电路;对传感器的温度漂移特性进行讨论,建立温度补偿算法模型。在温湿度箱中标定红外CO_(2)传感器参数,通过拟合曲线得到常数a和n,以及温度补偿系数β。经过实验测试表明,该红外CO_(2)传感器测量误差小于真值的±5%。

Aiming at the problems of large volume and poor sensitivity caused by the separation of the gas chamber and signal processing module of traditional infrared gas sensors,based on non-dispersive infrared dual-channel detection technology,a small-sized and high-precision infrared CO_(2)sensor was designed.First,ray tracing simulation on the reflective gas chamber was performed to ensure that the infrared radiation received by the pyroelectric detector and the gas absorption optical path length met the requirements.At the same time,a reliable light source drive circuit and bandpass amplification circuit were designed,the temperature drift characteristics of the sensor were discussed and a temperature compensation algorithm model was established.The parameters of the infrared CO_(2)sensor were calibrated in a temperature and humidity chamber,and the constants a and n,as well as the temperature compensation coefficientβ,were obtained by fitting the curve.Experimental tests show that the measurement accuracy of the infrared CO_(2)sensor reaches±5%of the true value.