Abstract: A method and apparatus for providing welding type power is disclosed. A welding type power supply includes an input circuit, a controller and an output circuit. The input circuit receives an input power signal and provides an intermediate power signal. The output circuit receives the intermediate power signal and provides a welding type power output. The output circuit has an inverter with at least two inverter switches, and a clamp circuit that limits the voltage across the inverter. The clamp circuit captures and buffers the excess energy, and returns the excess energy to an input of the inverter over a plurality of switching cycles. The controller has control outputs connected to the input circuit and the output circuit, to control them.

Abstract: A method and apparatus for providing welding type power is disclosed. A welding type power supply includes an input circuit, a controller and an output circuit. The input circuit receives an input power signal and provides an intermediate power signal. The output circuit receives the intermediate power signal and provides a welding type power output. The output circuit has an inverter with at least two inverter switches, and a clamp circuit that limits the voltage across the inverter. The clamp circuit captures and buffers the excess energy, and returns the excess energy to an input of the inverter over a plurality of switching cycles. The controller has control outputs connected to the input circuit and the output circuit, to control them.

Abstract: An example welding-type power supply includes: a transformer having a primary winding and first and second secondary windings; an input circuit configured to provide an input voltage to the primary winding of the transformer; first, second, third, and fourth switching elements, and a control circuit configured to: control the first, second, third, and fourth switching elements to selectively output a positive or negative output voltage without a separate rectifier stage by selectively controlling ones of the first, second, third, and fourth switching elements based on a commanded output voltage polarity and an input voltage polarity to the transformer; and prior to changing from a first output voltage polarity to a second output voltage polarity, controlling the first, second, third, and fourth switching elements to reverse the power flow to return reactive energy to an input circuit via the transformer.

Abstract: Methods and apparatus to provide welding power are disclosed. An example welding-type power supply includes: a transformer having first and second secondary windings; switching elements configured to control current flow from the first and second secondary windings to an output; and a control circuit configured to control the switching elements to selectively output a positive output voltage or a negative output voltage without a separate rectifier stage by selecting, based on an output voltage polarity, a first subset of the switching elements to perform rectification.

Abstract: A method and apparatus for providing welding type power is disclosed. A welding type power supply includes an input circuit, a controller and an output circuit. The input circuit receives an input power signal and provides an intermediate power signal. The output circuit receives the intermediate power signal and provides a welding type power output. The output circuit has an inverter with at least two inverter switches, and a clamp circuit that limits the voltage across the inverter. The clamp circuit captures and buffers the excess energy, and returns the excess energy to an input of the inverter over a plurality of switching cycles. The controller has control outputs connected to the input circuit and the output circuit, to control them.

Abstract: A method and apparatus for providing welding type power is disclosed. A welding type power supply includes an input circuit, a controller and an output circuit. The input circuit receives an input power signal and provides an intermediate power signal. The output circuit receives the intermediate power signal and provides a welding type power output. The output circuit has an inverter with at least two inverter switches, and a clamp circuit that limits the voltage across the inverter. The clamp circuit captures and buffers the excess energy, and returns the excess energy to an input of the inverter over a plurality of switching cycles. The controller has control outputs connected to the input circuit and the output circuit, to control them.

Abstract: Methods and apparatus to provide welding power are disclosed. An example welding-type power supply includes: a transformer having first and second secondary windings; switching elements configured to control current flow from the first and second secondary windings to an output; and a control circuit configured to control the switching elements to selectively output a positive output voltage or a negative output voltage without a separate rectifier stage by selecting, based on an output voltage polarity, a first subset of the switching elements to perform rectification.

Abstract: Welding-type power supplies with adjustable AC current commutation thresholds are disclosed. An example welding-type power supply includes an interface device to receive a commutation selection input, a power converter to convert input power to welding-type power, a commutator circuit to output alternating current (AC) welding-type power and to control a polarity of the AC welding-type power, and a control circuit. The control circuit determines a threshold output current based on the commutation selection input, determines an output current and a polarity of the AC welding-type power and, when the output current is less than the threshold output current, controls the commutator circuit to change the polarity of the AC welding-type power.

Abstract: A method and apparatus for providing welding type power is disclosed. It includes having a switched preregulator, where the preregulator is soft switched, and the components used to implement the soft switching are protected.

Abstract: A method and apparatus for providing welding type power is disclosed. A welding type power supply includes an input circuit, a controller and an output circuit. The input circuit receives an input power signal and provides an intermediate power signal. The output circuit receives the intermediate power signal and provides a welding type power output. The output circuit has an inverter with at least two inverter switches, and a clamp circuit that limits the voltage across the inverter. The clamp circuit captures and buffers the excess energy, and returns the excess energy to an input of the inverter over a plurality of switching cycles. The controller has control outputs connected to the input circuit and the output circuit, to control them.

Abstract: A method and apparatus for providing welding type power is disclosed. It includes having a switched preregulator, where the preregulator is soft switched, and the components used to implement the soft switching are protected.