Digital Submerged Arc Welding System Based On ARM

Submerged arc welding(SAW) is widely used because of its high efficiency, excellentquality and good working conditions. There are some issues such as power conversionefficiency is not high, the heat input control is not precise in the analog control rectifier DCpower supply which is generally used in the SAW system, currently. In recent years, thecontrol of welding power has shifted from analog control to digital control with the rapiddevelopment of digital control technology and power electronics technology. Digital inverterwelding power supply with higher reliability and more precise control effect can ensure betterwelding quality. Hence, the paper supported by the National Natural Science Foundation ofChina (No.E51375173) and the Core Technology Research Project in Strategic EmergingIndustries of Guangdong Province (No.2012A032300007). In this paper a fully digital SAWsystem based on double inverter topology was designed and developed to achieve fine controlof current waveforms and high conversion efficiency.Firstly, this thesis briefly describes the characteristics of SAW and expounds SAWprocedure development status and trend, the thesis also introduces the SAW systemdevelopment status and problems in main power supply and control system both at home andabroad. On this basis a design thought that a fully digital AC square wave SAW system hasbeen proposed.Then, the main circuit of SAW power supply with double inverter topology has beendesigned for achieving fine control of electrical energy conversion efficiency and waveforms.The first inverter circuit choose a full-bridge inverter topology, the second inverter choose adouble half-bridge inverter circuit parallel topology. Then the paper analyzes the workingprinciple and control method of double inverter circuit and calculates the main parameters ofthe device, also selects devices.Based on the above work, design requirements of control system in hardware andsoftware have been proposed according to the characteristics of the AC square wave SAW.The paper develops a digital system based on Cortex-M3kernel ARM chip LM3S8971chip,and designs sampling circuit, communication circuit, and other peripheral circuit design. Atsame time, the paper designs related hardware and software anti-jamming measures to ensurethe AC square wave SAW system can work stably and reliably in the complicatedenvironment.