Design Of High Power Phase-shifted Full Bridge Digital DC Power Supply

Today's era is the rapid development of power electronics technology era,Switching Mode Power Supply(SMPS)has penetrated into the daily life of people in various fields,including digital products,communications equipment,electrical equipment,industrial automation and control.In some areas of carrier communication,the equipment is subject to foreign technology blockade or extremely expensive,especially in certain areas of national security involving communications,the key equipment can not achieve localization of manufacturing means that the constraints of foreign countries,and may threaten national security.Therefore,the development of large-scale military equipment power supply is of great significance.This paper begins with the development background of SMPS technology,and introduces the current research status and development trend of SMPS technology.Focusing on phase-shifted full-bridge(referred to as PSFB)working state of gradual and in-depth analysis.The conditions of ZVS in PSFB circuit are summarized and analyzed,and the reasons of duty cycle loss are analyzed.The method of using nonlinear saturated inductance instead of traditional linear inductor is proposed to make the PSFB circuit not only reduce the duty cycle loss but also increase the zero-voltage turn-on range of the hysteresis arm.Secondly,the AC/DC converter circuit,the DC/DC power unit and the related hardware circuits of the high power PSFB digital DC power supply are designed and calculated.The power supply circuit,sampling circuit,drive circuit,communication circuit and other main control circuits are designed around the power supply master-slave control system controller(CPU).According to the characteristics of the peak current control mode,the digital realization method of PSFB circuit is given.On this basis,the parallel scheme of multi-power unit module is put forward.Thirdly,based on BUCK converter,a mathematical model of 30 kW full-bridge power unit is built,and digital PI parameters are determined by MTALAB software.In the PSIM simulation environment to 30 kW power unit experimental verification,the experimental program is a good realization of the PSFB control strategy,with anti-interference ability.The experimental results show that the PSFB control strategy can achieve soft switching in the range of 30% load,the efficiency is over 90% at 60% load,the full load efficiency is about 94%,the output voltage is stable and high efficiency.Finally,the power unit layout,control board,the host computer for the relevant design,built a 30 kW power unit of the experimental platform.The waveforms of ZVS waveforms and power waveforms of the power unit are analyzed in detail.And 12 power units of 30 KW in parallel assembly of 300 kW high-power DC power supply.The experimental results show that all parameters meet the requirements of the power supply of the long wave emission system.