Patent ID: 11883912
Assignee: DAIHEN CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC B  H | IPC B  H

Claim 0:
1. A welding power supply device comprising:
an inverter circuit that converts DC power into AC power and outputs the AC power to a welding load; and
a voltage superimposing circuit that superimposes a restriking voltage on an output to the welding load when a polarity of an output current of the inverter circuit switches,
wherein the voltage superimposing circuit includes:
a restriking capacitor to be charged with the restriking voltage;
a charging circuit that charges the restriking capacitor with the restriking voltage; and
a discharging circuit that discharges the restriking voltage charged in the restriking capacitor,
wherein the charging circuit includes:
a DC power supply that outputs DC voltage;
a voltage booster that boosts the DC voltage of the DC power supply; and
a current sensor that is arranged between the DC power supply and the restriking capacitor and inside the charging circuit and that detects a current inputted to the charging circuit,
wherein the charging circuit charges the restriking capacitor in both a first state and a second state following the first state during a period of time between an occurrence of discharging the restriking voltage and a next occurrence of discharging the restriking voltage, the first state being a state in which the DC voltage of the DC power supply is directly applied to the restriking capacitor, the second state being a state in which the DC voltage boosted by the voltage booster is applied to the re-striking capacitor, and
wherein the charging circuit switches from the first state tothe second state when a value of the current detected by the current sensor decreases down to a predetermined current value for a first time after a most recent one of at least one event that a value of the output current of the inverter circuit changes to its minimum or maximum value occurs.