The Research Of High Power Factor Soft Switching Inverter Welding Machine

It not only brings opportunities for welding science with the development of new technique,new technics and new material, but also makes it facing new challenges. New demand for welding power supply is one of them. The inverter welding machine has the merits of high-efficiency, low-wastage, low quality, little volume, low noise, easy controlling, what's more, a big development has been made in the aspects of improving power factor at AC side and faster dynamic response. Therefore, the inverter welding machine has become one of the main stream of modern welding power supply, nowadays. The techniques, PWM soft switching, active power factor correction(APFC), electric-magnetic compatible and electric-magnetic interfere design, simulation research and brainpower controlling are the new focus of welding power supply. In this paper, a multifunctional welding machine is designed with the characters of high power factor, soft switching and portable remove.As for the inverter welding machine, the time of the input current is very short, the shape of it is a sharp waveform, showing the character of non-sine wave at the AC input side. It contains heavy harmonic currents, thus not only leading to a rapid decreasing of the Power Factor (PF) of the arc welding inverter supply but also seriously polluting the power system. However, the single-phase soft switching and APFC technique is applied into arc welding inverter power supply in this paper, in order to improve the PF, that is Boost ZVT-PWM Converter. The merit of this APFC circuit is that the main power component is zero-voltage transition (ZVT), increasing the switching frequency and the efficiency.Due to its advantages of full bridge that is lower current,voltage pressure, the symmetry structure and high efficiency of the power transformer, the topology of the main converter, FS ZVZCS-PWM FB DC/DC Converter, is adopted in this paper. There are some merits in this converter, that the leading bridge is zero-voltage switching (ZVS), the lagging bridge is zero-current switching (ZCS), the current of the first side of transformer is lower, the loss of second side is decreasing.