基于过程控制的机载高光谱定标光源的快速稳定恒流源研制

Development of fast and stable constant current source of onboard hyperspectral calibration light source based on process control

定标光源的稳定性及稳定速度直接影响机载高光谱仪光谱辐射定标的准确性和效率。为实现定标光源的快速稳定,提出并设计了基于数字过程控制的恒流源快速稳定调节方法和系统。该快速稳定恒流源系统,在场效应管恒流源的基础上,加入数字过程控制环节,弥补场效应管恒流源反馈振荡调节及系统热稳定时间长的不足。快速稳定调节方法分为能够快速产生热量的大预置值启动快速预热、减小过冲振荡现象的缓冲快稳和输出稳定电流的模拟闭环稳流三阶段。快速稳定恒流源与场效应管恒流源对比实验表明:输出1500.00 mA电流,纹波系数达到1?的时间由670 s缩短到66 s;作为标准光源中卤钨灯的驱动电路,上电2 min后连续测量20 min获得的400~2500 nm光谱数据全谱平均基线漂移由0.5%降低到0.06%。

The stability and steady speed of the calibration light source directly affect the accuracy and efficiency of spectral radiation calibration of the onboard high-resolution spectrometer.To realize the rapidness and stabilization of calibration light source,a fast stabilization regulation method and a system of constant current source based on digital process control are proposed and designed.Based on the constant current source of field effect tube,the rapid constant current source is added with digital process control link to make up for the shortage of feedback oscillation regulation of field effect tube constant current source.The long thermal stabilization time of the system can also be improved.The adjustment method of rapid stabilization can be divided into three stages,including large preset value starting fast preheating to produce heat quickly,buffer fast stabilization to reduce the overshoot oscillation and constant current of simulated closed-loop to output the stable current.Comparison experiments between the fast stable constant current source and the field effect tube constant current source show that the time deceases from 670 s to 66 s for outputting a current of 1500.00 mA and ripple coefficient 1?decreases from 670 s to 66 s.In addition,as the drive circuit of the halogen tungsten lamp of standard light source,the full-spectrum mean baseline drift of the 400 nm^2500 nm data reduces from 0.5%to 0.06%under the output spectrum of the standard light source for 20 minutes after being electrified for 2 minutes.