Development Of High-power Digital Switching Power Supply For The Preparation Of Multicomponent Thin Film Materials

The development of electric locomotives has benefited from a clear understanding of the shortage of natural resources,such as the rapid development of China’s highspeed rail subways and new energy vehicles,and these electric locomotives will cause magnetic leakage problems during operation.Good performance magnetic thin film materials are required for magnetic management.There are many thin film preparation methods,compared with traditional processes such as sputtering,the electrodeposition preparation process has obvious advantages in magnetic properties and has become a classic preparation process.This preparation requires a power conversion device.The switching power supply uses energy conversion and storage devices such as power switching devices,transformers,chokes,and electrolytic capacitors,which work at a high frequency(above 75KHz)state to complete the energy conversion process.It greatly saves space and cost and is more efficient than ordinary sources.Therefore,it has been widely used in material preparation,transportation,communications,and electricity-related fields.This subject designed a high-power digital power supply for preparing multicomponent thin-film magnetic materials by electrolysis.Its main technical parameters are: output current 100 A,output voltage 25 V,power factor greater than 0.9,and overall efficiency greater than 85 %.The main work of this paper divided into the following parts:1.The various topologies and thermal management methods commonly used in switching power supply design are compared.Determine the system structure.The switching power supply uses a two-stage topology of a front-stage active power factor correction stage and a phase-shifted full-bridge soft switch with synchronous rectification characteristics suitable for the background application of this subject;the thermal management system uses forced air cooling based on FPGA control Cooling method.2.The working principles of active power factor correction,phase-shifted full bridge,synchronous rectification,and soft switching are introduced,and the control circuit and power circuit of the two-stage circuit are designed.In the power circuit,based on the APFC principle,the power BOOST chokes,switching devices,and output capacitors are calculated and selected.Based on the principles of PSFB and SoftSwitching,the high-frequency transformer is designed.the auxiliary inductor and the parallel capacitor of the switching device are designed according to the resonance principle.Due to the loss of the duty cycle when the lagging leg resonates,an auxiliary resonance network is designed.Based on the principle of output filter,the inductor and capacitor of the output filter are designed in detail;Because the control IC has limited driving capability and one switch in each bridge leg of the full-bridge circuit is floating,the drive circuit is designed;Part of the network in the power circuit has high-voltage and high-current electrical characteristics.In order to use it safely,an isolated drive circuit is designed;The control circuit requires closed-loop adjustment of the power circuit,and an isolated sampling circuit is designed;For the control circuit,a power factor correction circuit is taken as an example,and a control loop feedback and compensation circuit is designed in detail.3.The thermal management system is divided into two parts: hardware and software.The hardware part is controlled by FPGA.Circuit modules such as temperature acquisition and communication are built.The software part is based on the μC / OS system.A multi-tasking operating system is developed to realize the concurrent execution of multiple acquisition and adjustment tasks.The control algorithm uses an incremental PID algorithm.Dynamically adjust the output pulse according to the temperature of the power device at different positions to control the stepper motor at different positions,so as to control the air flow to achieve the purpose of thermal management.In order to facilitate the use,the host is designed.The temperature threshold can be adjusted according to the different operation environment.After communicating with the client,adjust the thermal management tasks and display the real-time working status of the system.