Design And Research Of Resonant Efficiency Communication Power Supply Based On LLC

With the progress of the times,the rapid development of the communication system,communication and people’s lives are closely linked.Communication power is very important part of the communication system,its importance is increasingly prominent.Therefore,it is great engineering value and practical significance to study the communication power supply.In recent years,the communication power supply began to develop in the direction of high frequency,modularization and intelligence to meet the requirements of the communication system.Communication power supply has developed with two levels of topology structure.Including levels before APFC and after the dc/dc resonant converter.The power supply front stage topology is boost structure,and the second stage selects LLC resonant converter.The principle of the pre stage converter in the CCM mode was analyzed.The main circuit and control circuit are designed according to the design index of the converter.Meanwhile,peripheral circuit design and software process control of PIC16F1938 was given.Secondly,this paper introduces the topology of the dc/dc converter in the rear stage of the communication power supply,its working state at different frequency was analyzed,The equivalent model of half-LLC resonant converter is established by fundamental analysis method,the gain function of output voltage is calculated according to the simplified model.The voltage gain curve of resonant converter under different inductance and quality factor is plotted by Mathcad,and the noload characteristics and short circuit characteristics of converter are analyzed.According to the design index,the parameters of half-LLC resonant converter are designed,the TMS320F28035 is used as the digital controller,and the peripheral circuits such as isolation drive circuit and output voltage sampling feedback circuit are designed.Finally,the simulation model is built with saber software,simulating the input voltage and current of PFC circuit under different input voltage,output voltage under different load,output ripple voltage.For the half bridge LLC resonant converter,whether the switch tube can achieve the ZVS and different frequency of the resonant cavity current and the rectifier diode voltage and current under different input voltage in the full load range are simulated and verified.Experimental platform was constructed.a sample charger has been developed with the power of 500 W,the input voltage range of the vehicle power supply designed is AC90V~264V,the output voltage is 48 V.The experimental waveforms of the prototype are analyzed to verify the correctness and practicability of the design.