智能交通摄像机工作热负荷实验评价

Experiment Evaluation of the Operating Thermal Load of an Intelligent Traffic Camera

利用红外热像技术,对某新型智能交通摄像机工作热负荷状况进行实验研究,并针对相机核心功耗元件DSP(数字信号处理器)和FPGA(现场可编程门阵列)开展了模拟芯片实验。原机实验结果表明,相机工作热负荷对芯片性能的影响不容忽视,即便处于只进行图像采集而不做图像处理的较低功耗模式下,不加散热器时DSP芯片表面温度已接近设计上限,因而有必要进行相机散热结构优化设计。模拟芯片实验证实,芯片功率对其表面温度有显著影响,功率越高,芯片温度呈近似线性增长,同时散热器瞬时储热能力有所减弱,因此合理控制芯片功率可有效降低相机工作热负荷。对比分析相机辅助散热器热阻可知,该散热器效率较低,存在进一步优化潜力。

By using infrared（IR）technology,the thermal load of a new-type intelligent traffic camera was studied experimentally. In addition,model experiment with essential power components of the traffic camera,including the DSP（Digital Signal Processing）chip and the FPGA（Field Programmable Gate Array）chip,was carried out. The result with the operating traffic camera indicates that the influence of thermal load on chip performance can not be ignored. When the heat sink of the camera is removed and the image processing function is deactivated,the surface temperature of the DSP chip still approaches to the upper range value although the camera is under low-power condition. Therefore,it is very necessary to perform optimal design with the heat conductive structure of the camera. As for chip model test,it is found as the power input increases,the steady temperature of chip surface increases linearly and the transient heat storage capacity decreases simultaneously. Due to the significant influence of chip power input on surface temperature,the thermal characteristic of the traffic camera can be effectively controlled by maintaining chip power input in a reasonable range. Comparison analysis of the heat sink resistant shows that the heat sink efficiency of the camera remains at low level and needs further optimization.