The Development Of The New Arc Welding Generator

Develop a new type AC Generating-DC Arc Welding dual use welding generator driven by diesel, which can be applied to the field welding-operation such as the building of the pipeline, the railway, the bridge, etc. It adopts a triple frequency harmonic-excited synchronous generator. And it can generate a 50~75V alternating-current through a single-phase welding-winding, and through a rectifier it can be used to welding, and need not the transformer; It can generate a 380V alternating-current as accessional power source through a three-phase winding. The welding generator has the characteristic of striking easily, a big arc force, and rapid dynamic response velocity.The welding generator can control the volt-ampere characteristics of welding power source and regulate the voltage automatically through the same control circuit. The control circuit is based on the method of PWM, which is modulating the width of the control pulse but not changing the frequency, and it samples and processes the instantaneous wave (but not the average value) of the output voltage and the welding-current when welding, and creates the control pulse which can control the generator's excitation through modulate the width of the pulse of the controlling cell-IGBT; It regulates the welding current through controlling the excitation of the generator. The method can reflect the changes of the welding parameter really and quickly through modulating the sample signals directly but not through the filter which can make a delaying, and it is helpful for the control circuit to make a rapid response, and it can improve the dynamic response velocity of the control system when the arc length changes, and improve the dynamic performance of the welding process, and it can solve the questions of arc breaking off, arc extinguishing ,etc, well when welding using a small welding-current(60~90A) in the downward welding of the cellulose electrode.At last, makes a simulation to the dynamic characteristic of the welding generator with the mathematics software-Matlab through building the model of the welding generator and the arc load; Analyses the influence of the DC inductance to the welding dynamic characteristic, the dynamic response velocity of the control system when the arc length changes and the control process; Compares the influence of the different inductance to the response velocity of welding current; Prove the correctness of the power source designing and optimizes the control circuit of the welding generator on the basis of the simulation.Experiments show that the welding generator fits for the welding of the cellulose electrode very much, which is adopted largely in the downward welding of the oil and gas pipeline, and it has gotten a well welding technical effect in tryout. In addition, the generator can provide a steady 380V three-phase alternating-current, which can drive heavy load tools such as a polishes an air-compressor and so on.