The Research Of Heating Power Supplier For Thermostatic Chamber Of Optical Telescope Based On LLC Series Resonant Topology

The high precision temperature controlling system is extremely important to the heavy caliber astronomical telescope observation system.The working temperature of heavy caliber astronomical telescope is from-35? to 35?,and the temperature change will lead to the tiny shape change which will influence the measurement accuracy.For this reason,the temperature controlling system is the premise to the proper functioning of the telescope.This paper is about a heating power supplier for temperature controlling in astronomical telescope.The output voltage and rate of the designing power supply is 24 v and 200 W.The paper mainly analyzes the production of electromagnetic interference(EMI)and distribution of the harmonic in switching mode power supply.Not only the influence of EMI to image formation in CCD is discussed,but also the superiority and necessity of the switching mode power supply replaces the traditional liner ones in this paper.Firstly,the topology of power factor correction circuit of heating power is introduced,the result that EMI of the Boost active power factor correction circuit is weaker is proved,and semiconductor companies' power factor correction chip NCP1605 is adopted to achieve circuit design on the controlling of active power factor correction.Secondly,the advantages of the LLC resonant converter-lower EMI higher efficiency is demonstrated,and a better design cycle of LLC resonant converter is proposed by theoretical analysis,the working conditions for the ZVS of the LLC resonant switching transistor and ZCS of output commutation is deducted.In the end,the best resonance parameter is got through the Psim stimulating process and the control circuit of LLC resonant converter is designed by adopting L6599,which is a high voltage harmonic chip developed by STM Microelectionics.Through above mentioned steps,the experimental prototype is designed,checking and analysed.Finally,it has been uninterruptedly tested for 72 hours in Nanjing Institute of Optics,Chinese Academy of Sciences,showing its testing result can almost meet previous experimental expectations.