Design Of Radar Chassis Thermal Control System

Radar has become a worldwide competitive focus of modern military technology the reliability of which has also become a critical subject. Among the causes of failures of electronic equipments such as radar, temperature is the major one, which holds approximately 55%.Therefore the design of thermal control system is an indispensable link. Recently, the thermal control system design mainly follows the traditional methods which brings an uncontrollable redundancy, high power and loud noise during its working, without radical improvement. Focused on a certain radar chassis, an optimizing approach for thermal design has been put forward and a real-time temperature controller has been designed.Firstly, an overall scheme of this system is made. According to the constraint of structure and requirement of thermal dissipation, the way of heat dissipation and its layout is discussed and then a cooling solution using DC driving axial flow fan for temperature control is made. Secondly, the thermal design is optimized. A mathematical model involves air flow, air pressure and air channel size is established for the fan selection. Building further on this foundation, the author researches a thermal design optimization base on PSO and works out the optimum results. Then, type of fan is picked on the basis of these results. Furthermore, simulation of this model is carried out using Ansys Icepak for its validation. What’s more, a PID temperature control system is built. In this design, FPGA acts as a main controller, DS18B20 is the temperature sensor and RS-232 is used for communication. The control logic of modules is compiled in VHDL by Quartus II. After that, all of the modules are simulated by Modelsim. And then, on the PC, a temperature monitoring interface is designed by VB6.0.After the chassis having been completed, its high-temperature resistance is tested in the high temperature test chamber. After what it improves about the design on the basic of test results, the high temperature test is repeated. By trial and error, finally the parameters setting of PID control and its environmental simulation test that resulted in two good temperature controlling curves are completed.