Study On Three-phase Inverter Arc Welding Power

For a long time, foreign products have occupied a half of our welder market, because of the low level of design, manufacturing process backward and poor reliability reasons, our domestic welder competition in the market at a disadvantage. Since the beginning of reform and opening up, China has imported and developed a number of advanced welding equipment and technology. China has not only improved the welding equipment design and manufacturing standards, but also the variety of equipment, and the specs been enriched and developed. Our welding industry has made considerable progress, but compared with the industrialized countries, there is still a big gap. To change this situation, and catch up with the international advanced level, we must study and master the advanced welding design, and handle technology, developed suited to China's national conditions and prices low and the quality of domestically produced excellent welder. Meet domestic needs, the foreign exchange earned through exports, its significance seems to be inevitable. The topic is on the market after studies prepared and to a certain extent practical significance.Inverter arc welding power is one of the main development direction of electric welding powers,which help to realize the mechanization and the automation.As a result of inverter arc welding power's many advantages, the paper is to conbine the production need of welding power factories and the development of welding power's market to study three-phase inverter arc welding power ZX7-250 (i.e. ARC250).The overall trend of inverter welding power is toward high-capacity,lightweight, efficient, modular, intelligent development and to improve reliability.It will be widely used in varieties of arc welding methods, resistance welding, cutting process and so on.It will be widely used for switching devices of inverter arc welding power,such as IGBT,MOSFET,and they are the current mainstream and direction of the development of the international welding power. The high-frequency development of inverter arc welding power is depanded the development of DC arc welding power in a great extent:from thyristor inverter arc welding power of 2~5kHz to BJT inverter arc welding power of about 10kHz,and to IGBT inverter arc welding power of 20~30kHz.With the rapid development of the electric power device,the frequency of inverter arc welding power is already up to 100 ~ 200kHz present.Through market research, the topic of the thesis is "Study On Three-phase Inverter Arc Welding Power ". First of all,we analyzed the development and application of inverter arc welding power,researched the level of study and use at home and abroad,and preliminary designed the main performance parameters of inverter arc welding power.Secondly, we designed the inverter main circuit of inverter arc welding power,which include filtering input rectifier circuit, full-bridge inverter main circuit and rectifier output filter circuit, and selected AC→DC→AC→DC inverter system.That is to achieve the conversion and transmission of electricity,and is the main part of the inverter power. The three-phase full-bridge rectification and filter circuit, the MOSFET full-bridge control model, and the center-tap full-wave rectification and output circuit were used in this paper.MOSFET inverter arc welding power with excellent arc performance,which style is K2611,can ignite the electric arc in a very short time, and can satisfy technical requirements of the quick shutter speed, the small switching loss, and the stable work state. Ferrite core material,which is selected EE series, is cheap and suitable for high-frequency inverter arc welding power, with small high-frequency loss, bigger electronic resistivity than silicon plate. It may further reduce forward voltage drop of diodes with parallel using,which were selected high-power fast recovery rectifiers.Inverter main circuit is simple,convenient and of compact structure.Thirdy ,we designed the inverter control circuit inverter arc welding power, which include power supply circuit, given circuit, Current negative feedback circuit, driver circuit, PWM circuit and protection circuits. The function is to control the inverter main circuit, the output characteristics, the regulation of welding parameters and other functions, such as protection, parameters preset and demonstration and so on.We chose ASIC KA3525A as PWM circurt of inverter arc welding power,of which pluse width modulation signal is reliable,stable and fully able to meet the working conditions of MOSFET.Finally ,we made a three-phase inverter arc welding power.We measured waveforms of different points and drawn external characteristc curves through repeated experiments and debugging of inverter arc welding mechine.According to the external characteristic curves,the inverter arc welding power can obtain good external characteristic curves in different output current from 30A to 220A,and has met the welding process requirements.In addition,the processing tests of the three-phase inverter arc welding power carried on about 5mm low-carbon steel plate with alkaline welding rods and acid welding rods separately. According to the processing tests, the welded joints were of good formation.It indicated that the inverter arc welding power has acheived the design request at first.