Research On High-power-factor & Soft-switching Arc-welding Inverter

This thesis gives a detailed analysis of the operation principle and the limitation of soft-switching of the traditional topology of phase-shift full-bridge ZVS PWM converter which is widely used in arc-welding power supply. For the traditional phase-shift full-bridge ZVS PWM converter has some certain disadvantages, the thesis emphasizes on the research of phase-shift full-bridge ZVZCS PWM converter. The topology of phase-shift full-bridge ZVZCS PWM converter with saturable inductor is chosen as main circuit. The thesis designs the main circuit combining the conditions to achieve soft-switching, and gives the design principles. On the basis of analyzing dynamic and static features of arc-welding power supply, the control system is also designed. An experimental arc-welding inverter of 250A/10kW is manufactured according to the before-mentioned principle. Experimental results are given at the end of each part of the thesis. PFC technology is a hot spot in the filed of power electrics now, because many countries have set the standard of limitations on harmonic pollution. The thesis also does some research on three-phase PFC technology. It analyzes several three-phase PFC topology at first, then gives a new solution of three-phase PFC which is composed of three directly-paralleled single-phase Boost PFC. It completely eliminate interaction among three single-phase PFC, and achieve systemic power factor correction and harmonic control. This solution has the advantages of simple construction and good harmonic control efficiency, and it can fully use the mature single-phase PFC technology. So this solution is a practical one. At last, the result of simulation can verify the possibility of the solution.