An apparatus to provide welding power. The apparatus may include a direct current-alternate current (DC-AC) power converter to output a primary current and a transformer stage. The transformer stage may include at least one power transformer to receive the primary current from the (DC-AC) power converter on a primary side of the transformer stage and to output a first voltage through a first rectifier and a first set of secondary windings disposed on a secondary side of the transformer stage. The transformer stage may further include an auxiliary set of secondary windings disposed on the secondary side to output a second voltage. The apparatus may also include a pair of active unidirectional switches disposed on the secondary side to receive the second voltage from the auxiliary set of secondary windings.

Embodiments of welding systems and methods for reducing spatter in pulsed welding are disclosed. A welding power source includes a first welding output stud to be electrically connected to a consumable welding electrode and a second welding output stud to be electrically connected to a workpiece. Power electronics generate welding output current pulses. A switching network is connected between the power electronics and the first welding output stud. A controller is connected between the power electronics and the switching network. The controller controls the timing of each welding output current pulse and switches the switching network back and forth between a first welding output current flowing state and a second welding output current impeding state based on the timing. An increase in a decay rate of a trailing edge of each welding output current pulse is effected during the second welding output current impeding state.

Systems and methods are described to address issues associated with welding with cored wires. In certain processes, a welding wire may “stick” or fuse to a contact tip. To mitigate the negative effects of a wire fusing to a contact tip, a double pulse waveform is applied. A first pulse is applied at a first current level above a threshold current level required to transfer a ball of molten welding wire in a peak phase, and a second pulse is applied in the background phase at a second current level below the threshold current level to limit and/or eliminate fusion between the wire and the contact tip. In examples, the second current level is sufficient to dislodge a spot weld between the welding wire and the welding torch yet insufficient to transfer a ball of molten welding wire.

There is provided an arc welding method. In the method, welding is performed in a spray transfer mode by feeding a welding wire. A first welding current Iw1 is flown during a first period. A second welding current Iw2 is flown during a second period. A third welding current Iw3 is flown during a third period, where 0<Iw2<Iw3<Iw1. The first to third periods are alternately repeated.

A method is performed in a welding or cutting system having a power inverter to generate an alternating current (AC) signal responsive to pulse width modulation (PWM) that is applied to the power inverter to control the AC signal. The method includes: upon detecting a power increase event in the welding or cutting system that necessitates an increase in the AC signal, controlling the PWM to cause the power inverter to increase the AC signal over multiple PWM cycles by: generating a first PWM cycle having a first period and a first on-time corresponding to a first duty cycle of the first PWM cycle that is greater than 50%; and generating a second PWM cycle having a second period that is greater than the first period and a second on-time corresponding to a second duty cycle of the second PWM cycle that is greater than 50%.

A system and method of welding or additive manufacturing is provided where at least two welding electrodes are provided to and passed through a two separate orifices on a single contact tip and a welding waveform is provided to the electrodes through the contact tip to weld simultaneously with both electrodes, where a bridge droplet is formed between the electrodes and then transferred to the puddle.

An arc welding method of a consumable electrode type generating arc between a tip end of welding wire and a to-be-welded portion by feeding welding wire to the to-be-welded portion of a base material while supplying welding current having average current of 300 A or larger to the welding wire, to weld the base material, includes: feeding the welding wire at a speed of the tip end being inserted into a space surrounded by a concave melted portion formed in the base material by the arc generated between the tip end and the to-be-welded portion; periodically alternating between a small current period where the welding current has a small average value and droplet is transferred from the tip end to a bottom part of the melted portion and a large current period where the welding current has a large average value and droplet is transferred from the tip end to a side part of the melted portion; and controlling the welding current in the large current period so that droplet transfer from the tip end to the side part is performed a plurality of times in each large current period.

A method includes ramping down a welding current, generated by a power supply, that reaches a welding zone via a welding circuit, storing inductive energy from the welding circuit that is generated as a result of the ramping down to obtain stored energy, and selectively feeding the stored energy to the welding circuit.

A welding system and method provide for generating a controlled waveform for welding power output, the waveform comprising a plurality of successive peak phases designed to avoid or reduce micro-arcing when used with metal-cored or flux-cored electrode wires. Ratios of the background current and voltage levels are elevated as compared to conventional techniques, with the levels in most cases exceeding 50% of the peak currents and voltages. Transitions between background and peak levels of current and voltage are also smoothed, and the duration of the peak phase as compared to the duration of each pulse cycle is elongated to further reduce micro-arcing.

An arc welding method alternately generates a short-circuit state and an arc state. In the method, short circuits are generated also in the arc period. This more than doubles the total number of short circuits, which is the sum of the short circuits generated in the short circuit period and those generated in the arc period. This enables a thin plate to be arc welded at a higher speed, while reducing its burn-through.