Research On Digital Inverted Power Supply For Plasma Arc Cutting

With the development of manufacturing in both technology and scale, a higher requirement of cutting quality and efficiency has been raised, considering the gradually increasing amount of cutting material. Plasma arc cutting, as a modern cutting technology, is playing a more and more important part in cutting area. The performance of cutting power, the core equipment, determines the cutting quality and efficiency. The existing inverted plasma cutting power supply, still using analog circuits control, results that the pulse characteristics of plasma arc can not be effectively regulated, which has great influence in both cutting quality and efficiency. This article focuses on research of digital inverted power supply for plasma arc cutting under such a project background. The work improves system accuracy fundamentally by using intelligent technology control strategy based on the digital hardware platform. This subject has important practical significance.The digital main control system is the key to realize digital inverted power supply for plasma arc cutting. This article has designed digital control system with the high-performance controller TMS320LF2407A as the core, improved the accuracy and reliability of the system and realized real-time, effective online control of cutting process. Interactive system is an important manifestation of digital degree of plasma arc cutting power supply. The paper has designed digital interactive system whose core is mixed-signal microcontroller C8051F020K+ to realize information, intelligence and other functions. As a result of independent design program for human-computer interaction system and main control system, this all-digital inverted plasma arc cutting power supply can adapt to complex cutting process better.The paper proposes a new intelligent control strategy considering the dynamic coupling of multiple cutting process parameters, the uncertainty of the optimal output, the requirement tracking the reference control of the power itself. We get the reference cutting current of closed loop controller through its nonlinear mapping ability by combining RBF neural network and expert system; the PID algorithm parameters are self-adjusted through fuzzy logic, whose inputs are both the reference current error and its variation rate to achieve servo control of the system's real-time changes.Finally, with MATLAB as the simulation platform, we build system simulation model to verify the stability and robustness of system performance, and the probability of the algorithm. We verify the advantage of this digital inverted plasma cutting power whose cutting current is 200A from the aspect of cutting quality although comparative cutting test.