Power Factor Correction For Single-Phase Arc Welding Inverter Power Source

Arc welding inverters are more and more widely used in our country, but most of the existing arc welding inverters create non-sinusoidal narrow pulse current waveforms at the AC input side. It has serious distortion and contains heavy harmonic current, thus leads to a rapid decreasing of the Power Factor(PF) of arc welding inverters and seriously polluting the power system.After referring to plenty of the reference, the single-phase soft-switch active power factor correction (APFC) technique is applied into arc welding converter in this paper . It makes a useful attempt upon the application of soft-switch APFC technique to arc welding converter. The following is done in this paper:The average current control APFC circuit is chosen as the APFC control circuit of the single-phase welding inverter based on the analysis and summary of the exiting popular single-phase input APFC circuit.The control rules of the average current control APFC circuit's main components are discussed in details and the equations of the current and the voltage passing through the main components are obtained .The transfer functions of the current and voltage for system correction are given based on the analysis of the average APFC circuit. The parameter of the circuit is optimized through the Saber simulation software.In order to overcome the problems of the hard-switch PFC circuit, a zero-voltage transition topology of APFC technique is introduced in the arc welding converters. The process of the ZVT PFC circuit is analyzed in details and the resonance parameters are calculated.A 3000W PFC equipment for arc welding converter is developed using soft-switch technique. The waveforms of input current are measured. The results show that the input PF is increased obviously and the input current total harmonics distortion (THD) is less than the international standard of 5%. The pollution to power system is decreased effectively.