Scm Inverter Submerged Arc Welding Machine System Design

The application, history, actuality and foreground of SAW-tech are firstly introduced in the introduction part of this paper. The far-reaching affects of micro-chip technique combined with inverter technique on the development of welding machine are follow set forth. According to the shortcomings of traditional SAW, a direction of studying on microprocessor control IGBT inverter for submerged arc welding is put forward.The component parts and control principle of pulsed SAW inverter power source are mainly introduced in the paper. The main circuit, pulse width modulation circuit, drive circuit, safeguard circuit as well as wire feeding and tractor circuits are respectively analyzed. Hard ware and soft ware are both expatiated systematically.The main circuit is made up of rectifier, filter, high-frequency transformer, output reactor, and full-bridge inverter, where 4 IGBT are adopted. The key points in designing high-frequency transformer, as well as the characteristics of IGBT are discussed. At the same time, in order to obtain accurate and real-time control, high performance 16-bit microprocessor 80C196KC is adopted for control kernel. In the power source, a PWM technology and the current feedback PI algorithm is used to adjust the output volt-ampere characteristic of power source. The digital signal from microprocessor are firstly converted into analogy signal, which is then modulated by pulse width modulate (PWM) chip SG3525 into two pulses not overlapped each other. At last the pulses are used to spring IGBT after they are magnified. The PWM switch powers are applied in wire feeding and tractor speed control system. The voltage feedback PI algorithm is used to adjust wire-feed speed, which is controlled with closed-loop. The pulses are respectively produced by PWM chip SG3524 and HSO.O of MCU. In addition, the functions of peripheral circuit are given. The safeguard circuit mainly consists of over-current, over-heat, over-voltage and low-voltage circuits. The system control software is made up of modular subroutines, the function of each subroutine is introduced in detail. According to the control characteristic of much tasks of SAW, some optimization designs are used in software, which have coordinated each controlled procedure rationally.Reliability and noise resistance designs are also covered. In order to reduce their bad infections, some hardware and software measures are adopted The experiment results indicates: The control system has many advantages such as simple circuit, high control precision, strong anti-interference ability, intelligible man-machine dialogue and reliable performance. It can meet the request of power source and process control of SAW and has improved comprehensive performance of the welder and automatic degree.At last, the design of double electrodes SAW and some improved advices are put forward in allusion, which are expected to make the whole system more reliable and more ideal.