用于离轴积分腔技术的温控系统设计研究OACHSSCD

Aims:To enhance the measurement stability of the off-axis integrated cavity output spectroscopy system,a high-precision temperature control system was designed;and the influences of heat dissipation structure and temperature control points on temperature control effect were investigated.Methods:A temperature control circuit was constructed with the STM32 F103 microcontroller as the core.A high-precision temperature measurement unit was established using PT1000 platinum resistors and the AD7793 analog-to-digital converter.An integral separation PID algorithm was adopted to generate 100 Hz pulse width modulation(PWM)signals to drive the heating film.Four combinations of cooling fans with different power ratings and quantities were configured to conduct comparative experiments on temperature control performance at four characteristic positions on the surface of the integrating cavity.Results:The system achieved the optimal performance when adopting a heat dissipation structure with two low-power fans(single fan power:0.96 W)and selecting appropriate temperature control points.In 2-hour steady-state tests,the temperature fluctuation of the cavity was controlled within±0.015℃,with a measurement standard deviation of 0.003 9℃.Conclusions:The heat dissipation structure is the critical factor affecting temperature control performance.Although the high-intensity heat dissipation structure with three high-power fans(single fan power 1.8 W)shortens the temperature rise time to approximately 3 412 s,it introduces a large steady-state error of about 0.034℃.In contrast,the low-intensity heat dissipation structure with two low-power fans has a slightly longer rise time of roughly 3 878 s,yet its steady-state error is significantly reduced to 0.002℃,making it more suitable for high-precision spectral measurement applications.