Research On Key Technologies Of Fine Plasma Cutting Power Supply

With the continuous development of plasma cutting technology in recent years,the processing quality of fine plasma cutting has approached laser cutting,and the cost of plasma cutting equipment is much lower than laser cutting,so fine plasma cutting has attracted more and more attention of metal processing industry.However,at present,the domestic plasma cutting equipment is mainly concentrated in the low-end cutting field,and the market of fine plasma cutting equipment has been monopolized by foreign companies.In order to break the technical barriers,this subject is entrusted by the enterprise to research and develop the fine plasma cutting power supply.Firstly,this paper designs the overall scheme of fine plasma cutting power supply.Through comparison and demonstration of the schemes,the power module adopts parallel Buck chopper topology,and through the state space averaging method,the main circuit of the system is modeled,and the system stability is analyzed in frequency domain.Then,the hardware circuit of fine plasma cutting power supply is analyzed and designed.Software control is designed,variable parameters PI control strategy and machine tool-electric integrated control method are adopted in arc stabilization stage to improve the dynamic response performance of output current.Next,aiming at fine plasma cutting with small holes,an automatic gas control cabinet is designed,which effectively improves the cutting performance by combining automatic gas control with current control scheme.And finally,the solutions are given for the CCC certification detection,the visualization platform for real-time display of variables,and the problems found in thefield application such as electromagnetic interference.The fine plasma cutting power supply is tested on the cutting test platform.The experimental results show that the current ripple rate is 0.6%when the cutting current is 200 A and the cutting material is low carbon steel.The obtained workpiece has good cutting effect in both the small hole and the outline: the corner of the workpiece is sharp,the inclination of the cutting surface is less than 1 degree,and the cutting surface is clean,with little slag hanging.The cutting quality meets the technical requirements of fine plasma cutting,basically reached the cutting level of foreign products.