Thermal Model Based Microchannel Cooling Control System

Due to its high thermal efficiency and compact structure, Microchannel cooling technology is widely applied to the heat dissipation of electronic devices. With the cooling requirements of electronic devices become higher and higher, micro-channel cooling system needs to do more than just be capable of dissipating the heat emitted from the device, but also quickly make adjustments according to the cooling demands, aiming at avoiding the emergence of excessive temperature fluctuations. Therefore, developing one kind of micro-channel cooling system that can response quickly and be intelligent-agent controlled is meaningful. In this paper, based on the thermal model of a micro-channel with dual-channel structures, a micro-channel cooling control system was designed. The performance of the whole system was experimentally tested and analyzed.The thermal model of a microchannel with dual-channel structures was established in detail. According to its structural characteristics, it was divided into three parts. The heat transfer processes and boundary conditions of each part were analyzed. The analysis formulas of thermal resistances were given. And the expression for the average temperature of the heat source was obtained through the established thermal model.According to the established thermal network model, the factors that affect the total thermal resistance were discussed. Curve fitting was adopted to get a simplified expression of the total thermal resistance. Based on this, the algorithm for thermal control systems was established and a specific implementation plan was developed. After the connection between the control voltage of system actuator and flow rate of the micro-channel was obtained with the experimental method, the design of the entire thermal model based cooling control system was completed.The performance of the designed cooling system was tested on the conducted experiments. During the experimental measurement, a typical step signal was employed to test the response curve of the system. Experimental results show that the thermal model based control cooling system is capable of controlling the heat source temperature under a predetermined range. It verifies the reasonability of the designed system. Simultaneously the experiment of a traditional PID control system using the same microchannel and actuator were performed for comparing, the results show the advantages of thermal model based control lie in its shorter regulation time, a smoother control process and a smaller system overshoot. Under tested circumstance, its shortest regulation time is only 76.28% of the regulation time of the PID control. And its maximum system overshoot is only 2.31%, while the minimum system overshoot of PID control is 8.91%. Thus, the overall performance of thermal model based cooling control system is privileged among the comparison.