Research On Key Technology Of Weak Electromagnetic High-precision Incubator

Thermostatic test chamber has a wide range of needs and applications in aerospace research institute and high precision electronic chip field.According to the law of electromagnetic induction,magnetic field in the closed traverse can produce induced current due to the change of magnetic flux,so for high precision electronic sensor chip performance test,in order to avoid the induced current in the constant temperature box test,impact test chip precision,need in the constant temperature environment of non-magnetic or weak magnetic test and production test.In view of the current our country small incubator is hard to in weak magnetic interference and high precision temperature control and problems that could satisfy the requirement of high precision electronic sensor chip test,paper according to the institute of space a new electronic sensor chip need to be placed in the weak magnetic high-precision constant temperature test chamber for a long time electricity test project requirements,The weak magnetic field technology and temperature control technology of small incubator are studied.Firstly,by analyzing the basic theory of electromagnetic field,the electromagnetic field model of the incubator is constructed,and the intensity of AC current magnetic field and DC magnetic field of the incubator is simulated and analyzed by finite element analysis.Secondly,according to the theory of heat transfer,the mathematical model of temperature rise and constant temperature heat balance of the thermostat is established,and the alternating heating mode of both sides of DC current and the combination control scheme of gradual DC temperature rise and constant temperature are put forward,which greatly reduces the influence of electromagnetic interference on the performance test of high-precision electronic sensor chip.In the control algorithm,the Smith fuzzy PID control algorithm is applied to the heating phase to ensure the uniform control of heating rate and heating current.The Dahlin control coordination algorithm is added to the conventional PID control,which effectively ensures the accuracy of constant temperature control and no overshoot in the process of mode switching.Finally,the structure of the incubator and the software and hardware of the system are designed.The simulation experiment and system test results show that the design of the weak magnetic constant temperature test chamber basically meets the requirements of the technical indicators of the enterprise,the constant temperature accuracy is better than 0.1℃,and the change of electromagnetic induction intensity caused by each current change is less than 0.3u T.The maximum field strength tested was less than 200 u T.The research of the miniaturized magnetic low-intensity and high-precision constant temperature test chamber provides a stable magnetic low-intensity constant temperature environment for enterprises to test the performance of high-precision electronic sensor chips,preliminarily solves the technical difficulties of the magnetic low-intensity constant temperature chamber,and can meet the scientific research needs of related industries.