Development Of Auxiliary Power For EDM Power Supply System

In this thesis,the design of the special auxiliary power supply for the power supply system of the EDM is the main line.According to the demand of the power supply system,a 380V AC voltage input,± 15V and +24V output auxiliary power supply prototype is designed and produced.Considering the contradiction between the withstand voltage ability of the chip itself and the large input voltage,TOP224YN is connected with MOSFET.This method solves the problem of voltage withholding successfully.Since high-frequency switching devices are often used in switching power supplies,EMI signals are generated during operation.Therefore,in order to reduce the influence of EMI,the SIwave and Desigenr software are used for co-simulation analysis and improvement of the EMC of the auxiliary power supply.The specific work of this thesis is as follows.Firstly,the basic theory of switching power supply design,including the design principle,the topology of the main circuit and design methods,is analyzed in detail,and the working principle,working mode and design method of the flyback switching power supply are analyzed emphatically,which lays the foundation for the selection of the components and the calculation of the parameters.Secondly,on the basis of grasping the necessary theory,the design of the power supply is expounded in detail.It mainly includes input and output rectifier filter circuit design,clamp circuit design,control system circuit design based on TOP224YN,high frequency transformer design,sampling and protection circuit design,etc.Then the schematic diagram of the whole power supply is designed,and the power circuit is simulated by Saber.The correctness and rationality of the circuit design parameters are verified.Then,the layout and wiring rules of PCB are described in detail,the PCB of power supply is designed preliminarily and the field circuit co-simulation of the PCB is carried out by SIwave and Designer software.Through the analysis of the mechanism of PCB interference and the simulation results,this thesis improves the PCB,and the improved PCB is simulated near-field again,it is proved that the improved PCB EMC performance is better than before improvement by comparison.In addition,through the 3m simulation,it is determined that the radiated noise of the power PCB is within the scope of the national standard GB 4824-2013,and meets the design standard.Finally,the auxiliary power supply prototype is debugged and the main waveform of the power supply is analyzed,including the input and output voltage and current waveform,the Vds and Vgs waveform of MOSFET,the output voltage ripple and so on.The test results of the prototype show that all the indexes of the power supply are in conformity with the requirements,and the output is stable and the performance is good.