The Full Digital Igbt Inverter Mig / Mag Welding Power Supply

The application of power electronic technology in welding yield results in miniaturization and high electronic efficiency of welding inverter. But, as the development of technology, the shortcomings of traditional analogue control circuit have become the bottleneck for further promotion of the welding inverter power. According to the characteristics of digital signal processing, the digitalization of welding inverter and its future development on the basis of illumination of the DSP's basic characteristics are introduced. At the same time aiming at current research status, the paper discusses the necessary of this investigation.Firstly, the control principle, characteristics and chip selection of DSP are introduced in the paper. The paper focuses on component part and control principle of digital GMAW -P (pulse MIG welding) inverter power. Main circuit, control circuit, pulse width modulation (PWM) circuit, drive circuit and wire feeding circuit are respectively analyzed. Furthermore, the software and hardware aspects are also addressed.Main circuit, which applies IGBT full-bridge inverter structure, is made up of rectifier, filter, high-frequency transformer and output reactance. The key points and parameters of the design are discussed in detail. To realize real time closed loop control, high performance 16-bit DSP TMS320F240 is adopted as control kernel. Using universal PWM method means to control output power and output characteristic through controlling IGBT switch on time. Because TMS320F240 can not directly generate requisite pulse waveform with dead-band, a special separate frequency circuit is designed. The separate two pulses trigger IGBT after they are magnified by exclusive drive module M57959L. The system samples output current and welding voltage in real time, and uses PI control algorithm realize the purpose of control output characteristics of welding power.Reliability and anti-jamming are considered in main circuit and control circuit. System software, which is made of modular subroutines, is very efficient for limiting noise and improving system response-speed.The circumstance of simulation is necessary for designing DSP system. The paper illuminates DSP develop circumstance CCS2. 0 and develop tool XDS 510 in detail.Corresponding data and waveforms are recorded, and problems occurred in experiment are investigated. The experiment results verify that the inverter power source has rapid response-speed, high reliability, a strong ability of anti-jamming and good human-computer interface.At last, some advices on future research of the welding power are given, and they will make a found ground for tomorrow's research of digital welding power.