Design Of Thermoelectric Refrigeration Temperature Controlling System For EMCCD Camera

As a high-speed and high-sensitivity image sensor in the world today,EMCCD has a wide application prospect in aerospace,night vision navigation,biomedicine and many other applications.In order to reduce the influence of its hot and dark current and increase its electron multiplication gain,it needs to be deeply cooled,and in order to stabilize its electron multiplier gain,the cooling temperature is required to have a high degree of stability.At the same time,in order to reduce the impact of temperature changes on the camera,in the cooling,the temperature change rate should be slower.Therefore,it is particularly important to have a high degree of stability of the EMCCD and to ensure a suitable temperature change rate.In order to meet the above requirements,this paper designed a refrigeration control system,the system use the TMS320F28335 digital signal processor as the master chip,and use the PT1000 temperature sensor to collect EMCCD camera chip temperature data,then the system take the data as a parameter Of the PID control algorithm to calculate the amount of control,by setting the voltage across the TEC to control the EMCCD camera chip temperature.Firstly,this paper discusses the application prospect of EMCCD and the importance of deep cooling for its high stability.Then,according to the requirements of cooling performance and the existing experimental conditions,the control system took the TMS320F28335 as the master chip and selected the various components to satisfy the system requirements.The hardware circuit of the control system includes temperature measurement circuit based on PT1000 and AD590 temperature sensor,AD conversion circuit,DSP core control circuit,drive circuit based on DA converter and OPA549,drive circuit based on MOS tube switch and a temperature control circuit board.Then,according to the characteristics of the system,this is paper designed the software based on the integral limit PID control algorithm.Then the simulation comparison of the conventional digital PID algorithm and the integral limit PID control algorithm was made in Matlab / simulink.Finally,the temperature control experiment was completed on the experimental platform.The simulation results of Matlab / simulink show that the PID control algorithm with integral slicing is superior to the conventional PID control algorithm in overshoot and control stability.The experimental results show that the system can keep the temperature control stability at ± 0.1 ? and the temperature change rate is less than 5 ? / min,which can meet the system performance requirements when the TEC is provided with large cooling power.