A power converter nearly losslessly delivers energy and recovers energy from capacitors associated with controlled rectifiers in a secondary winding circuit, each controlled rectifier having a parallel uncontrolled rectifier. First and second primary switches in series with first and second primary windings, respectively, are turned on for a fixed duty cycle, each for approximately one half of the switching cycle. Switched transition times are short relative to the on-state and off-state times of the controlled rectifiers. The control inputs to the controlled rectifiers are cross-coupled from opposite secondary transformer windings.

High efficiency power converter

A method and apparatus for welding include initiating a pulse welding process includes initiating a welding arc by providing CC type welding power, maintaining the arc by providing CV type power. Then, pulse type welding power is provided. The method and system can be used to start short circuit, or other welding processes by providing short circuit power, or welding power of a given mode, instead of providing pulse power. Also, in one alternative, a method and system of initiating a pulse, short circuit, or given welding process includes initiating a welding arc by providing CC type welding power at least until a pseudo-equilibrium for the arc is established. Then, providing welding power in a pulse, short circuit, or the given mode.

Method and apparatus for welding

An arc welding machine comprises an output control circuit (2) which produces an arc output in accordance with output control signal, an output detection circuit (3) which measures the state of arc output and produces a feedback signal indicative of the output arc state, and a fuzzy inference control circuit (1) which introduces the feedback signal, produces a welding current waveform and welding voltage waveform required to produce the optimal arc state based on the fuzzy inference, and delivers the resulting waveforms to the output control circuit as the output control signal.

ARC welding machine

A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert the input into a first internal AC signal, an isolation transformer with a primary winding driven by the first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert the second internal AC signal into a second DC output signal of the second stage, with a magnitude related to the duty cycle of the switches; and, a third stage to convert the second DC output signal to a welding output for welding wherein the input stage has a regulated DC to DC converter with a boost power switch having an active soft switching circuit.

Three stage power source for electric ARC welding

An arc-welding method, which comprises: arc-welding objects of welding together along the line of a groove formed between said objects of welding by continuously moving a welding electrode along the line of said groove while reciprocating said welding electrode in the width direction of said groove; characterized by: calculating at prescribed time intervals, for each one reciprocation of said welding electrode in the width direction of said groove, deviations (l-lo) of values (I) of one of arc current and arc voltage from a previously set reference value (lo), for each of left-side deviations (L) and right-side deviations (R) relative to the vertical plane which passes through the center of amplitude of said one reciprocation of said welding electrode and is parallel to the line of said groove; calculating at said time intervals, when said welding electrode moves over the left side of said groove relative to said vertical plane, differences (L-R) between said left-side deviations (L) and the immediately preceding right-side deviations (R), to controllably aligning the center of said amplitude of said one reciprocation of said welding electrode with the center of said groove In the width direction thereof at said prescribed time intervals so that said differences (L-R) become null; and, calculating at said prescribed time intervals, when said welding electrode moves over the right saide of said groove relative to said vertical plane, differences (L-R) between said right-side deviations (R) and the immediately preceding left-side deviations (L), to controllably aligning the center of said amplitude of said one reciprocation of said welding electrode with the center of said groove in the width direction thereof at said prescribed time intervals so that said differences (L-R) become null.

Arc welding method

A short circuiting arc welding machine increases an arc current density by adding a pulsed current having upper and lower limits to a current flowing when an arc is produced, thereby increasing the depth of bead penetration into a workpiece, removing welding defects, and speeding up the welding operation. The welding machine is capable of alternately changing the direction of flow of a welding current at desired periods to produce arcs in straight, reverse and mixed polarities for achieving intermediate characteristics of arcs of straight and reverse polarities, with a resultant ability to adjust in a wide range a wire melting rate and the amount of heat applied to the workpiece.

Short circuit transfer arc welding machine

A DC arc welding apparatus compares the output voltage with an adjustable, preset voltage, and the amplified and integrated difference signal is supplied to a current control circuit together with a current feedback signal. The resulting apparatus operates in a constant voltage mode, thus rendering it applicable to consumable electrode welding. A constant current mode may also be realized, as an alterantive, by bypassing the comparator and feeding the preset voltage directly to the current control circuit.

Constant voltage DC arc welding apparatus

A power source includes first and second control circuit for controlling the current provided during short-circuit and arc intervals, respectively. A transistor in series with the power supply is controlled in response to either of the control circuits.

Consumable electrode type arc welding power source

A consumable electrode type arc welding apparatus in which arcing can be positively started under a variety of welding conditions. A start current detector selects a predetermined limited start current according to the welding conditions. A start current period setting unit sets a start current period, also in accordance with the welding conditions. A start current control circuit supplies the predetermined limited start current to the workpiece and the wire electrode for the predetermined period of time at the start of arcing.

Consumable electrode type arc welding apparatus having a selectable start current

An arc welding robot control system includes a control console where a plurality of points on a workpiece taught by a teaching box and a welding voltage, a welding current and a welding speed set by a key board to be specified to each of the taught points are stored in a central control unit and displayed on a cathode ray tube, and a welding electric source for selectively delivering two sets of a welding voltage and a welding current which are specified for a pulsed and a short arc welding process respectively. With the pulsed arc welding process displayed, a set of normally open contacts disposed within the central control unit is closed to cause an electromagnetic contactor disposed within the welding source to operate the source with the that process. Otherwise the contact set is maintained open to operate the source with the short arc welding process.

Hirohisa Segawa

Papers

Short circuit transfer arc welding machine

Constant voltage DC arc welding apparatus

Consumable electrode type arc welding power source

Consumable electrode type arc welding apparatus having a selectable start current

Arc welding robot control system