Research On New Soft-switching Arc Welding Inverter

The development, trend and application of arc welding inverter and soft-switching technique is firstly introduced precisely. On the shortcoming of existing arc welding inverter, such as the big switching tension of main power transistor, the large wastage of machine, the low reliability and the pollution for the electric net, the settlement using soft-switching technique is brought and the research statement about soft-switching circuit topology is summarized. This paper mainly introduces three types phase-shifted control soft-switching circuit topology: zero voltage switch (ZVS), zero current switch(ZCS),zero voltage zero voltage current (ZVZCS),especially FB ZVZCS PWM converter's theory and micro-working process is analyzedBased on the circuit topology, the main circuit and control system of the converter is designed. FB ZVZCS PWM circuit is used in the main circuit, including the design of main transformer, rectifier, filter, and full bridge resonant converter. Using the current closed loop PI system and establishing the delivering function, the external circuit on UC3875, driving circuit on 1GBT, the control PCB power supply circuit, welding process control circuit and several protesting circuit is designed. Fully allowing on the reliability in design, we as far as possible make the circuit uncomplicated as well as fulfill all the function Based on the analysis and design, a soft-switching arc welding inverter typed with ZX7-200ST IGBT is developed and implemented Checked with the digital oscilloscope on the spot, the waveforms of the control circuit are given and the four section driving-waveform is stable. The IGBT of ZVS for leading-leg switches and ZCS for lagging-leg switches has been presented and the double zero switches in the inverter are fulfilled.The inverter has the goodness of high-efficiency low-wastage, low quality, little volume and low noise. Showing through the experimental result, the arc welding inverter has excellent dynamic and static character, invariable current stabilizatioa It is a new type power source with wide developing prospect.