Computer Control Multi-function Igbt Inverter Welding Machine

There are many shortcomings, such as complicated control-circuit, bad performance, less reliability, lower rate of function-price on national IGBT inverter power source. With the development of micro-chip technique and inverter technique on welding machine, the paper studied on the task about the versatile IGBT inverter power source which can use for GMAT(CO2, Ar) and GMAT-P(pulsed MIG welding).The component parts and control principle are firstly introduced in this paper. Main circuit, control circuit, pulse width modulate(PWM) circuit, drive circuit, wire feeding circuit and system software are respectively analyzed.The main circuit is made up of rectifier, filter, full-bridge inverter which is adopted 4 IGBT, high-frequency transformer, output reactance. The design key points and parameters are discussed in detail. At the same time, in order to obtain accurate output characteristic and output power, high performance 16-bit micro-processor 80C196KC is adopted for control kernel. The digital signals out of micro-processor are firstly converted into analog signals which is then modulated by PWM chip SG3525 into two pulses not overlapped each other. At last the pulse are used to trigger IGBT after they are magnified by M57959L. The safeguard circuit mainly consists of over-current, over-heat, over-voltage, low-voltage protected circuit. In addition a wire feeding system is designed, which takes PWM principle.The control system is a close-loop system. It can sample the welding parameters at real time and then use PI controller to adjust the system output. The system control software is made of modular subroutines, which is very efficient for limiting noise and improving system response-speed.The experiment results show that the inverter power source has rapid response-speed, high reliability, a strong ability of anti-jamming and good human-computer interface.At last, the design which is adopted advanced digital signal processor (DSP) for control kernel is discussed. This control system based DSP can realize digital-control and make a found ground for tomorrow's research.