| Up to now,mid and high-end fine plasma power supply market has been monopolized by European and American enterprises.Although research and trial-production of fine plasma power supply has been carried out domestically,there are few products to realize producibility temporarily.In order to change this situation,this paper studies and tests many key technologies in the producibility process of plasma power supply,and improve product uniformity and reliability.First,the interleaved parallel Buck topology is anayzed according to the technical requirements of fine plasma cutting technology,and the components of the main power circuit are designed and selected.The smallsignal model based on circuit-average method is established and the compensation network which can optimizate the dynamic characteristics is selected.IIR filter is designed to realize the compensation network digitally,which is simulated and verified by Matlab/simulink.Afterwards,incremental digital PI control algorithm is designed and the PI control parameter turning strategy of each stage during plasma cutting is designed in order to improve the reliability of cutting process and prolong the lifecycle of consumable accessories.Then,the influence of processing parameters on bolt hole cutting effect is analyzed and theoretical value is calculated.The cutting parameter database of fine bolt holes is obtained through correction of tests.And the code conversion process of CNC system is optimized for fine bolt hole cutting,which can greatly improve the cutting effect of bolt hole.Aferwards,three solutions for solving the stability problems faced in producibility of plasma power supply are proposed,including integrated PCB testing platform,program updating through wireless serial port and fast faults diagnosis using fault tree analysis.A prototype of fine plasma power supply is manufactured and the relation between component selection of main power circuit and output current ripple is tested.The PI control parameter turning strategies of arc starting and transfering,current rampup and rampdown stages are verified.The comparison of bolt hole cutting effect between cutting with the database and without the database is verified.The testing results show that the fine plasma power supply designed in this paper meets the technical requirements of fine plasma cutting and works stably and reliably,which can be applied to producibility. |
