Patent ID: 7141759

Claim:
A generator for unitary power factor arc welders, of the type comprising a current transformer that supplies, at a secondary winding thereof, a welding arc and is in turn supplied, at a primary winding thereof by an input leveling and rectifying unit, wherein between said rectifier unit and said transformer there is an interposed an electronic circuit with two electronic switches that provide a half-bridge structure that performs DC/DC conversion by way of the combination of the transformer and of a rectifier stage connected to the secondary winding of said transformer, and a leveling inductor, said circuit having a combination of resonant capacitive and inductive components arranged on the side of the primary winding of the transformer, said components charging a bank of capacitors parallel-connected to the electronic switches, furthermore keeping the voltage across it constant, means being also provided to control the welding current and to ensure sinusoidal-type absorption from the mains, the generator further comprising resonant circuit composed of a capacitor C R that is supplied by the input rectifier unit an inductor L R in series between the capacitor C R and the first terminal of the primary winding of the Dower transformer T, and a capacitor C T that is in parallel on the primary winding of the transformer T and wherein said control means use and process the voltage across the capacitor C R , the voltage across the capacitor C T , the current in the inductor L R , the set reference current I RIF and the welding current I F , generating a switching frequency that drives the two electronic switches S 1 and S 2.