Research And Design Of High Performance Programable Digital Linear Power Supply System

With the rapid development of modern electronic technology,the power requirements of electronic equipment are becoming higher and higher.Among them,the common adjustable linear DC power supply adopts a pure linear voltage stabilization structure to realize the principle is more traditional,while still basically adopts the mechanical operation mode of the combination of buttons and knobs.Therefore,in view of the defects of low power conversion efficiency,easy button failure,large size and bulkiness,and low output voltage accuracy of this power supply,this paper carried out the research work of adjustable linear DC power supply that meets the development needs of modern electronic technology.Based on the research,this paper designs a multi-stage series programmable digital linear DC power system.Under the premise of favorable power supply installation,the system is divided into four modules: AC-DC module,power adjustment module,digital control module and auxiliary board.The specific research work is as follows:First,in order to improve the power factor,reduce the harmonic pollution of the power grid,and improve the power conversion efficiency and power density,it was decided to use a two-stage series structure of Boost PFC plus LLC resonant conversion to implement the AC-DC module.Subsequently,the working principle and control method of Boost PFC circuit are analyzed in detail,and its parameter design is simulated and analyzed.The actual verification of this power factor is close to 1.Secondly,the paper analyzes the working principle of LLC resonant circuit in the different working frequency,and the equivalent circuit model of the LLC resonant network is established using the fundamental wave analysis method.The influence of the resonance parameters on the voltage gain and the various conditions under soft switching conditions are analyzed the relationship between the parameters,according to the actual design requirements,the parameter design method is given.According to the circuit simulation analysis and physical test,the LLC resonant converter can achieve high power density output and output efficiency of up to 91%Then,in order to make the fixed output voltage from the AC-DC modules realize stable output is adjustable,programmable adjusting module using Buck converter based on digital control fusion and the design scheme of the linear voltage regulation technology,the scheme combines switch power supply,linear power supply and the advantages of digital control,which can realize high efficiency,high precision and low ripple output.The working principle of switch pre-regulation circuit and linear post-regulation circuit is analyzed,the design method of core circuit of programmable adjustment module is given,and the simulation analysis and physical verification are given to realize the programmable output of the front stage following the rear stage and complete the highperformance output of programmable adjustment module.Finally,the functions of the digital adjustment module and the auxiliary board are analyzed,and the physical design of the two modules is completed.Subsequently,the overall architecture design of the system and the assembly of the hardware modules were completed.A power prototype was built and the performance of the power system was tested repeatedly many times in the laboratory.The experiment shows that the power supply can continuously adjust 1m V and 1m A step length in the range of 0-40 V and 0-5A,the power supply adjustment rate is less than 0.1%,the load adjustment rate is less than 1%,the ripple and noise are lower than 2m Vrms,the voltage accuracy reaches the set value of 0.03% +8m V,the maximum efficiency can reach 80%,and the machine weight is up to 3kg.It is superior to the DC power supply SPD3303 C used in the laboratory and has practical application value.In summary,this power system adopts the digital control method and incorporates the design scheme of switching voltage regulation and linear voltage stabilization technology to achieve the advantages of high efficiency,high accuracy,low ripple and low weight,providing a design for linear power supply design.