The hottest microcomputer controlled switching arc

2022-09-30
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Microcomputer controlled switching arc welding power supply [Abstract] this paper expounds the practical significance of developing switching arc welding power supply, analyzes the principle and composition of switching arc welding power supply and microcomputer control system, and makes some useful exploration in the development of new arc welding power supply. The microcomputer controlled switching arc welding power source designed by the author adopts high-power switching transistor to make it work in the state of "on" and "off", which overcomes the disadvantage of low efficiency of analog transistor arc welding power source, and the working state is relatively stable. At the same time, the single-chip microcomputer control is used to realize the preset function of welding parameters and the feedback control technology to adjust the welding voltage UF, so as to obtain the external characteristics required by the consumable electrode arc welding power source

classification number: tg434.1 document identification code: a

article number: 1001-2303 (2000) 02-0007-04

The Switching Welding Power Source Controlled by Microcomputer

WU Wan-hua et al

Shanghai Jiaotong University

Abstract:The paper introduces the practic value of the switching power source designed by the author and the system analysis of the principle and constitution of the power supply including the microcomputer controlling e author puts forward some vie wpoints about the new welding power e power source which is controlled by the microcomputer system in this paper is made use of giant transistor(GTR),and have it work in both the condition of “on”and “off”. Therefore, it overwhelms lower efficiency - the difference between the force direction or the strain coaxial with the force direction power source, and keeps a stable operation the measure, the power source makes use of single chip microcomputer controlling technology and realizes the function of welding parameters is power can also modify the welding voltage Uf through feed back controlling so to get constant voltage characteristic.

Key words:microcomputer control; switching type; Pulse width modulation ▲

1 overview

arc welding is the most important category of welding methods, and different arc welding processes require corresponding arc welding power sources. Without good arc welding equipment as a guarantee, it is impossible to get good welding quality. Therefore, arc welding equipment is one of the key research fields of welding workers in our country. In order to make a beneficial exploration in the development of arc welding power supply, I will take microcomputer controlled switching arc welding power supply as the research direction

because the high-power transistor group of the analog transistor arc welding power source is connected in series in the welding circuit and works in the amplified state, the welding current passed by the tube group is large, and the tube voltage drop is high, and the power loss is large (the regional difference of efficiency and even dispersion types is more obvious, and the rate is only about 40% when it is low), which not only consumes electric energy, but also makes the tube cooling system more complex. On the contrary, if the high-power transistor group operates in the switching state, this problem is solved, which is the switching transistor arc welding power supply

a high-power transistor working in the switching state, when it is "on" (saturated conduction), the current is large, the tube voltage drop is about 0, and the tube power consumption is very small. When it is "off" (cut-off), the tube voltage drop is high and the current is about 0. The power consumption of both States is small, so the efficiency is high and the cost is relatively low. The switching frequency of switching transistor arc welding power supply is generally very high, about 20 ~ 50KHz. The frequency remains unchanged during the working process. The specification and required external characteristics can be adjusted by adjusting the pulse duty cycle. Therefore, switching transistor arc welding power supply is ideal for MIG/MAG arc welding power supply

the leap forward of welding machine technology is mainly reflected in the control of arc welding power supply. With the emergence of new high-power electronic components and the integration of electronic equipment, the control of arc welding power supply has developed from the original mechanical control or electromagnetic control to more and more fully electronic control and microcomputer control

microcomputer controlled switching arc welding power supply has more functions and better performance than ordinary arc welding power supply, and has a wide application prospect. At present, a lot of manpower and material resources have been invested at home and abroad to research and develop this type of welding machine and its related fields, and the combination of microcomputer processing and switching consumable electrode arc welding power supply is a relatively new combination point. The author hopes to make some beneficial attempts in this regard

2 main circuit composition

the main circuit of switching power supply adopts the mode of series connection between switch tube and welding load, and introduces arc voltage feedback and current feedback control. The main object of control is welding arc, and the detection quantity is arc voltage UF. Therefore, voltage feedback is mainly used to realize constant voltage control, and current feedback plays an auxiliary role

the main circuit transformer adopts a star connected circuit. After three-phase AC is rectified by three-phase bridge, it is controlled by the high-power transistor GTR, and the load is in the "on" or "off" state, so as to supply the voltage and current required by the welding arc. Among them, the switching transistor is connected in series in the welding circuit, the capacitor C plays the role of filtering, L plays the role of energy storage, and the diode V plays the role of freewheeling, as shown in Figure 1

Figure 1 Schematic diagram of the main circuit of the power supply with a length of 38.9 meters

the voltage of the circuit is reduced and rectified, and then the intermittent pulse current is output through the transistor switch. If the input voltage is constant DC, the square wave is obtained through the transistor switch. If the input voltage is pulsating DC

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