| With the development of electrical technology, in order to meet the need of more functionality, electrical parts develop into high level of integration with more highperformance and high-power components integrated on them. Restricted by installation space or work ambient, electrical parts develop toward miniaturization direction. Once electrical parts work long hours in enclosed space or in high temperature, it will make much more difficulty in heat dissipating. All these above factors will inevitably contribute to thermal adaptability problem. Especially when electrical parts are used in the field of aerospace, the work space has wide temperature range. The temperature condition is harsh which will degrades performance of electrical parts and decreases system reliability, even shorten service life. The thermal failure of electronic device become more serious and is much greater than mechanical failure. To ensure adaptability to wide temperature range, this paper aimed at enhancing temperature adaptability of electrical parts. Selected thermoelectric cooler as temperature adaptability reinforcement technical approach, analyzed heat transfer characteristics of temperature adaptability reinforcement system. Based on above work, a thermal control system has been designed in order to create a suitable workspace ambient. Finally, the range of temperature environment adaptability has been enhanced from-40℃~+60℃to-55℃~+70℃.As a basis of heat transfer characteristic research and thermal control, it has great significance of researching thermoelectric cooler’s(TEC) performance characteristic. Firstly, this paper has adopted thermal resistance to mathematical modeling for TEC. Based on the model, the analytical solutions of heat flow generated by control side(cQ)and coefficient of performance(COP) in steady state. According to the analytic solution expressions, it has analyzed the influence of current and heat sink resistance on heat flow and coefficient of performance. Given each parameter’s value interval when the coefficient of performance is optimal under certain conditions.Then, contrary to the problem that it is difficulty to researching heat transfer characteristics of temperature adaptability reinforcement system by experimental or theoretical calculation of temperature field, through reasonable mechanism analysis and simplification, the thermal network and thermal balance equations have been built. Some uncertain thermal network parameters are extracted from thermal balance equations in order to compute them, including insulation thickness, heat load, heat sink size, optimal operating current of TEC and source power. Using these parameters and thermal balance equations, the junction temperature in workspace is obtained by iterative solution.Contrary to the disadvantage that the traditional thermal control method usually deal with the defect of thermal design when the prototype has been manufactured, this paper introduced temperature field thermal simulation before manufacturing prototype by software named FloTHERM in order to verify the design is reasonable. The software is based on numerical analysis of finite volume method.Finally, in order to thermostatically control the electrical parts workspace temperature, the TEC controller has been designed. Taking into account that the reinforcement system contains a plurality of sensors and multi-chip thermoelectric coolers, it has adopted one-way temperature control, temperature gradient deviation and PID algorithm as control strategies. Constructing thermal control experiment platform to do thermostatic control experiments. In extreme conditions, at low temperature-55 ℃,the reinforcement system can enhance the electrical parts workspace temperature to-22℃.When the ambient temperature is 70℃,the system can drop the workspace temperature to 50℃.All the experiments show the effectiveness of network analysis and the rationality of temperature adaptability reinforcement system design. |
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