Research On The Thermal Stability Improvement Of The High Definition Intelligent Traffic Camera

As an input element of ITS(intelligent transportation system), traffic cameras play a dominant role in the high efficient transportation management system. With the development trend of intelligence and digitization, the thermal flux of camera electric system has been rising increasingly. For practical engineering application, if the heat cannot be dispatched properly, excess temperature will cause many serious problems such as bit errors, packet loss, reboot and etc. Therefore, the electronics engineer has paid attention to research on the thermal stability of traffic camera. At the moment, the computational fluid dynamics(CFD) simulation in conjunction with traditional laboratory have become an important technological means in the process of product development, which can optimize the designing scheme and curtail the development cycle.By using infrared(IR) technology, the thermal load of a new-type intelligent traffic camera was studied experimentally. From this study, we can acquire infrared thermal images of camera radiator and electric system under the image acquisition mode. Moreover, the thermal simulation analysis of camera radiator and PCB was conducted by using Ansys-Icepak software. To verify the thermal simulation model, the infrared thermal testing result of traffic camera was employed. In the same way, the variation law of camera thermal load was studied under different environment temperature, and the result presented that the traffic camera has onerous thermal load, the radiator structure cannot provide enough protection for camera operation.Based on the empirical design, an optimum proposal about camera electric system layout was put forward. In addition, the effectiveness of improvement project had been demonstrated through the Ansys-Icepak software. The results indicate that the optimized layout of chips can decrease thermal load and relieve thermal stress concentration. A 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. So that the research limitation that the power of camera chips cannot adjust discretionarily was overcame. 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. Finally, this study established the analytic model of thermal resistance, analyzed the impact of various parameters on the characteristics of thermal interface materials, gap thickness, radiator material and convection pattern. Based on these results, an optimized design scheme of multiple objective was conceived.