Research On H Bridge Driven Circuit Of 110V Wire Feeding Motor In Submerged Arc Welding

Submerged Arc Welding (SAW) is a kind of higher production efficiency machine welding methods today. SAW has occupied the quite important status in the national economy because of high production efficiency, good welding quality and good working conditions. SAW is mainly used to weld kinds of steel plate structure. And SAW is widely used in Shipbuilding, boiler, chemical vessel, hoisting machinery and metallurgy machine-building industry. Automatic control has been used in the ignition of electric arc, welding wire-feed, movement of arc along welding direction, receiving arc of welding, etc.The stability of arc voltage is realized by adjustment of wire feeding speed in constant wire feeding system of SAW. Thus the stability of arc voltage is depended on that wire feeding speed is fast or slow. But the adjustment speed of wire feeding is subjected to the actual control system and the motor inertia. In some welding cases of high requirement to arc voltage and arc current, the usual wire feeding system is unable to meet the needs of wire feeding at present. In constant-current power supply to variable speed wire-feed system of SAW, the stability of arc voltage can be improved when using high-frequency, push-pull H-bridge driver wire-feed circuit. H-bridge driving circuit drives motor by PWM, and the motor is kept at motion state all the time, even if the condition of zero rotational speed. And then the motor inertia is largely reduced. The stability of arc voltage may be improved by H-bridge driving circuit used for wire feeding system.However, it is difficult that the commercial H-bridge motor driver module designed for low voltage motor is applied to wire-feed motor of SAW directly. Based on low-voltage H-bridge motor drive module L292, this paper designed a bipolar reversible H bridge wire-feed circuit in which the module circuit and the high voltage MOSFET driver circuit are isolated by high speed optocoupler. The results show that the application of high speed optocoupler is simple and effective when the voltage of module and the rated voltage of motor are different, and have realized the control of 110V wire-feed motor's direction and rotation rate by L292. The designed circuit has improved partly the hysteresis of wire feeding speed.