提出了一种差分光学吸收光谱(DOAS)测量中LED光源的恒温控制方法。采用半导体制冷片作为控温元件 来控制LED温度,应用PID算法动态调节半导体制冷片的工作电流,实现了DOAS测量过程中LED光源的温度 恒定。介绍了恒温控制系统的硬件设计和软件流程,并对控温效果和LED谱的稳定性进行了测试。测试 结果表明,提出的恒温控制方法能有效克服环境温度变化对LED光源温度的影响,温度控制精度达 到了±0.1℃。在相同的测试条件下与无恒温相比,具有恒温功能的LED光源剩余噪声明显偏低,进 一步验证了设计方案的可行性。

A method of thermostatic control of LED as light source for differential optical absorption spectroscopy (DOAS) measurements is presented. A Peltier is used to control LED’s temperature and its working current is regulated through PID algorithm in order to keep LED’s temperature constant. Hardware design and software flow of thermostatic control system is demonstrated, and the thermostatic control effect and stability of LED’s spectrum are tested. The results show that the impacts of ambient temperature on LED temperature are effectively restrained and ±0.1℃ of control accuracy is obtained. Compared with the LED without thermostatic control under the same condition, the residual noise of the LED with thermostatic control is markedly lower, which also proves the availability of this method.