Electronic welding apparatus

Abstract

An electronic welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply as a control element and preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed via an entry keyboard to a microprocessor where they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modultor which is connected to the driver stages of the power supply's switching stages which are designed as a boost regulator or a buck regulator, and thus a pulse width modulation of the current pulses of the switching stages is effected in dependence on the difference between actual and nominal values. Also fed to the microprocessor are the actual values of current and voltage which, together with other welding parameters fed in via the entry keyboard, such as rate of wire feed, wire thickness, type and pressure of the protective gas, watercooling etc., serve for monitoring the welding procedure.