# US 10,369,649 B2 · Circuits for improved welding performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,369,649 B2 - Document ID: US10369649B2 - Status: Granted - Kind: B2 - Application number: 14/817,283 - Filed: 2015-08-04 - Published: 2016-08-11 - Granted: 2019-08-06 - Earliest claimed: 2015-02-05 - Assignees: Lincoln Global, Inc. - Applicants: Lincoln Global, Inc. - Inventors: Robert L. Dodge; George B. Koprivnak; Steven R. Peters - Web page: https://patentgrep.com/patent/US10369649B2 ## CPC - B23K 9/073: Stabilising the arc - B23K 9/1062: {with computing means} - B23K 9/1081: {Arc welding by means of accumulated energy} - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract Welding circuits including superposition elements that charge and discharge to assist with re-establishing a welding arc between an electrode and a workpiece after the arc is extinguished when a welding output current polarity changes are described. ## Claims ### Claim 1 A system, comprising: a welding power conversion circuit configured to convert an input current to an output current; a plurality of switches and corresponding current paths including at least: a positive polarity main switch on a positive polarity current main path, the positive polarity current main path includes a welding path from an electrode to a workpiece, a positive polarity auxiliary switch on a positive polarity current auxiliary path and a polarity transition auxiliary path, a negative polarity main switch on a negative polarity current main path, the negative polarity current main path includes the welding path from the workpiece to the electrode, a negative polarity auxiliary switch on a negative polarity current auxiliary path and the polarity transition auxiliary path, and an independent discharge control switch on an independent discharge control current path; a controller that controls operations of at least one of the plurality of switches; and a superposition element configured to discharge stored energy in response to a polarity change in the output current, the superposition element configured to charge at least when current flows through the polarity transition auxiliary path, wherein the independent discharge control switch is operatively connected to the superposition element to control the discharge of the stored energy through the independent discharge control current path to the welding path, and wherein the superposition element discharges once per polarity cycle in response to the polarity change in the output current, and the polarity change is a negative to positive polarity change in the output current. ### Claim 2 (depends on 1) The system of claim 1, the positive polarity current main path and negative polarity current main path include a common active snubber circuit. ### Claim 3 (depends on 2) The system of claim 2, the common active snubber circuit includes at least a diode and a capacitor. ### Claim 4 (depends on 1) The system of claim 1, all of the positive polarity current auxiliary path, negative polarity current auxiliary path, and polarity transition auxiliary path include an inductor. ### Claim 5 (depends on 1) The system of claim 1, the superposition element charges at least during a deadtime associated with the polarity change. ### Claim 6 (depends on 1) The system of claim 1, the superposition element discharges to an independent discharge control path. ### Claim 7 A system, comprising: a welding power conversion circuit configured to convert an input current to an output current; a plurality of switches and corresponding current paths including at least: a positive polarity main switch on a positive polarity current main path, the positive polarity current main path includes a welding path from an electrode to a workpiece, a positive polarity auxiliary switch on a positive polarity current auxiliary path, a negative polarity main switch on a negative polarity current main path, the negative polarity current main path includes the welding path from the workpiece to the electrode, a negative polarity auxiliary switch on a negative polarity current auxiliary path, and a controller that controls operations of at least one of the plurality of switches; and a superposition capacitor configured to discharge stored energy in response to a polarity change in the output current, the superposition capacitor configured to charge by current flow through a polarity transition auxiliary path, wherein the superposition capacitor discharges once per polarity cycle in response to the polarity change in the output current, and the polarity change is a negative to positive polarity change in the output current. ### Claim 8 (depends on 7) The system of claim 7, wherein the positive polarity current main path and the negative polarity current main path include a common active snubber circuit. ### Claim 9 (depends on 8) The system of claim 8, wherein the common active snubber circuit includes at least a diode and a capacitor. ### Claim 10 (depends on 7) The system of claim 7, wherein the superposition capacitor charges at least during a deadtime associated with the polarity change. ### Claim 11 A system, comprising: a welding power conversion circuit configured to convert an input current to an output current; a plurality of switches and corresponding current paths including at least: a positive polarity main switch on a positive polarity current main path, the positive polarity current main path includes a welding path from an electrode to a workpiece, a positive polarity auxiliary switch on a positive polarity current auxiliary path, a negative polarity main switch on a negative polarity current main path, the negative polarity current main path includes the welding path from the workpiece to the electrode, a negative polarity auxiliary switch on a negative polarity current auxiliary path, and an independent discharge control switch on an independent discharge control current path; a controller that controls operations of at least one of the plurality of switches; and a superposition capacitor configured to discharge stored energy in response to a polarity change in the output current, the superposition capacitor configured to charge by current flow through a polarity transition auxiliary path, wherein the independent discharge control switch is operatively connected to the superposition capacitor to control the discharge of the stored energy through the independent discharge control current path to the welding path, and wherein the superposition capacitor discharges once per polarity cycle in response to the polarity change in the output current, and the polarity change is a negative to positive polarity change in the output current. ### Claim 12 (depends on 11) The system of claim 11, wherein the positive polarity current main path and the negative polarity current main path include a common active snubber circuit. ### Claim 13 (depends on 12) The system of claim 12, wherein the common active snubber circuit includes at least a diode and a capacitor. ### Claim 14 (depends on 11) The system of claim 11, wherein the superposition capacitor charges at least during a deadtime associated with the polarity change.