Inverter output rectifier circuit

摘要

In a power source of a welding system, an inverter rectifier output circuit and method for reducing the blocking voltages across saturable reactors associated with a rectifier coupled to a transformer winding in the inverter rectifier output circuit during both turn-on and turn-off transitions of the rectifier. At least a portion of a reverse recovery current associated with the rectifier is blocked by allowing blocking voltages to build across associated saturable reactors during a transition phase of the rectifier. During a turn-off portion of the transition phase, the blocking voltages are reduced using a RC circuit, thereby suppressing a peak voltage associated with the rectifier. During a turn-on portion of the transition phase, the blocking voltages are reduced using another saturable reactor in series with a free-wheeling diode.

主权项

1. An inverter rectifier output circuit, said circuit comprising:
a secondary winding of a transformer, said secondary winding having a first node, a second node, and a center tap node; a first saturable reactor connected to said first node; a first rectifying diode connected in series with said first saturable reactor at an anode of said first rectifying diode; a second saturable reactor connected to said second node; a second rectifying diode connected in series with said second saturable reactor at an anode of said second rectifying diode; a third saturable reactor connected to said center tap node; a free-wheeling diode connected in series with said third saturable reactor at an anode of said free-wheeling diode; a first series RC network connected between said anode of said first rectifying diode and said anode of said free-wheeling diode; a second series RC network connected between said anode of said second rectifying diode and said anode of said free-wheeling diode; a first output node defined by connected cathodes of said first rectifying diode, said second rectifying diode, and said free-wheeling diode; a second output node defined by said center tap node; wherein the third saturable reactor has an inductance less than the first saturable reactor and the second saturable reactor at least during switching.