Research On Soft-switching Mode Power Supply Of Arc-welding And Air-plasma-cutting

In the special power supply field, the inverter and soft switch technic is more and more widely used. A new soft-switch model power supply which can be used both in arc welding and air plasma cutting is proposed and studied in this thesis.There are two soft-switch schemes of phase-shift full-bridge DC/DC converter: zero-voltage switching (ZVS) and zero-voltage zero-current switching (ZVZCS). In this thesis the two schemes are compared and analysed. On the analyses of several typical ZVZCS circuit topologies, the topology of phase-shift full-bridge ZVZCS PWM converter with saturable inductor is chosen as main circuit finally. The thesis designs the main circuit combining the conditions to achieve soft-switching, and gives the design principles of some key parameters. Otherwise the arc-starting circuit using in air plasma cutting is also analyzed and simulated by matlab.On the basis of analyzing dynamic and static features of arc-welding and air plasma-cutting power supply, the control system is also designed. And the small-signal model of phase-shift full-bridge ZVZCS converter is deduced, which could be used in future digital system design. The program control system is also analyzed for air plasma cutting in addition.An experimental arc-welding and air plasma-cutting inverter of 250A/10kW is manufactured according to the before-mentioned principles. Experimental results are given at the end of each part of the thesis.