Abstract: An inverter for converting DC voltage into AC voltage, in particular a photovoltaic inverter for high power densities, in particular 250 W/dm3 to 500 W/dm3 power densities, has at least one DC input, an AC output, a heat sink, a printed circuit board, a DC disconnector, a DC-DC converter, an intermediate circuit, a DC-AC converter and a housing with a front cover and a basic shell. The electrical components of the DC-DC converter, intermediate circuit and DC-AC converter are combined into subassemblies. At least the DC disconnector and the subassemblies of the DC-DC converter, intermediate circuit and DC-AC converter are directly arranged on the circuit board in a U-shaped manner corresponding to the energy flow direction from DC input to AC output. The circuit board is arranged with the component side facing the base (65) of the basic housing shell and with the opposite side on the heat sink.

Abstract: A data transmission method for a resistance welding current source during a welding operation generates welding pulses in an inverter with inverter switching elements cyclically with a switching frequency and pulse duration. The pulses are applied to a transformer primary side and rectified on the transformer secondary side by a rectifier with rectifier switching elements to form a resultant welding current. In a data transmission mode the impedance at the primary side is increased in the breaks in the welding operation, control pulses for initializing the data transmission mode are applied by a control device to the primary side and are detected on the secondary side. The rectifier switching elements of the secondary-side rectifier are actuated in a way corresponding to the data to be transmitted. The current on the primary side of the transformer is modulated with these data, and the data are thereby transmitted via the transformer.

Abstract: A data transmission method for a resistance welding current source during a welding operation generates welding pulses in an inverter with inverter switching elements cyclically with a switching frequency and pulse duration. The pulses are applied to a transformer primary side and rectified on the transformer secondary side by a rectifier with rectifier switching elements to form a resultant welding current. In a data transmission mode the impedance at the primary side is increased in the breaks in the welding operation, control pulses for initializing the data transmission mode are applied by a control device to the primary side and are detected on the secondary side. The rectifier switching elements of the secondary-side rectifier are actuated in a way corresponding to the data to be transmitted. The current on the primary side of the transformer is modulated with these data, and the data are thereby transmitted via the transformer.

Abstract: A method for manufacturing a heavy-current transformer with at least one primary winding and at least one secondary winding with surfaces for contacting connects first inner surfaces of the at least one secondary winding with an I-beam of electrically conductive material of the heavy-current transformer with a first soldering material at a first, higher melting temperature, and subsequently at least one contact plate of electrically conductive material is soldered with exterior surfaces of the at least one secondary winding with a second soldering material at a second melting temperature that is lower as compared to the first melting temperature.

Abstract: The invention relates to a heavy-current transformer (12), in particular for a power source (10) in order to provide a welding current of a resistance welding device (1), with at least one primary winding (13) and at least one secondary winding (14) with center tapping, and to a transformer element, a contact plate (29) and a secondary winding (14) for such a heavy-current transformer (12) as well as a method for the manufacturing thereof. For reduction of losses and improvement of efficiency, at least four contacts (20, 21, 22, 23) are provided to form a multi-point contacting, said contacts (20, 21, 22, 23) being formed by four contact faces within which the at least one primary winding (13) and the at least one secondary winding (14) are arranged in a series/parallel connection.

Abstract: A resistance welding device includes a power source in order to provide a welding current for welding workpieces, a welding gun with two gun arms having one electrode each in order to impress the welding current into the workpieces. The power source includes a heavy-current transformer with at least one primary winding and at least one secondary winding with center tapping, a synchronous rectifier connected with the secondary winding and including circuit elements, and a circuit for actuating the circuit elements of the synchronous rectifier. For reduction of losses and improvement of efficiency, the power source is arranged at the welding gun and the power source includes at least four contacts forming a multi-point contacting, wherein two first contacts of one polarity are connected to one gun arm and two additional contacts of opposite polarity are connected to the other gun arm.

Abstract: A circuit arrangement for controlling a transistor with an insulated gate, a gate driver for generating a driver signal, and a capacitor parallel to the gate-source path of the transistor, wherein the gate driver is designed for generating a driver signal greater than or equal to zero volts, an inductor is provided for forming a resonant circuit with the capacitor, and a switching element is provided in the resonant circuit, which is designed for interrupting the resonant circuit after recharging the capacitor. The part of the circuit arrangement downstream of the gate driver is designed for exclusive voltage supply using the driver signal of the gate driver, and the switching element is formed by an additional transistor, a first freewheeling diode is arranged parallel to the switching element, and the inductor of the resonant circuit is arranged between the additional transistor and the gate of the transistor.

Abstract: The invention relates to an inverter (1) for converting a DC voltage (UDC) into an AC voltage (UAC), in particular a photovoltaic inverter for high power densities, in particular power densities of 250 W/dm3 to 500 W/dm3, having at least one DC input (5), an AC output (11), a heat sink (20), a printed circuit board (32), a DC disconnector (7), a DC-DC converter (8), an intermediate circuit (9), a DC-AC converter (10) and a housing (14) with a front cover (15) and a basic shell (16).

Abstract: A circuit arrangement for controlling a transistor with an insulated gate, a gate driver for generating a driver signal, and a capacitor parallel to the gate-source path of the transistor, wherein the gate driver is designed for generating a driver signal greater than or equal to zero volts, an inductor is provided for forming a resonant circuit with the capacitor, and a switching element is provided in the resonant circuit, which is designed for interrupting the resonant circuit after recharging the capacitor. The part of the circuit arrangement downstream of the gate driver is designed for exclusive voltage supply using the driver signal of the gate driver, and the switching element is formed by an additional transistor, a first freewheeling diode is arranged parallel to the switching element, and the inductor of the resonant circuit is arranged between the additional transistor and the gate of the transistor.

Abstract: The invention relates to a method for controlling an inverter and to an inverter a DC/DC stage, which comprises at least one main switch (S2) and a discharge circuit, and with a DC/AC stage. The discharge circuit is formed by a series connection of a bidirectional switching element, which comprises two switches (SA1, SA2), and an inductivity. A device is provided for controlling the switches (SA1, SA2) and is designed such that one switch (SA1, SA2) is activated in an alternating manner and the switch-on time of the switch is determined by the controlling device prior to a switch-off time of the main switch (S2).

Abstract: The invention relates to a power source (10) for providing a direct current, comprising a heavy-current transformer (12) with at least one primary winding (13) and at least one secondary winding (14) with center tapping, a synchronous rectifier (16) connected with the at least one secondary winding (14) of the heavy-current transformer (12) and comprising circuit elements (24), and a circuit (17) for actuating the circuit elements (24) of the synchronous rectifier (16), and a supply circuit (48) for supplying the synchronous rectifier (16) and the actuation circuit (17), and to a method for cooling such a power source (10). For reduction of losses and improvement of efficiency, the synchronous rectifier (16) and the actuation circuit (17) and the supply circuit (48) thereof are integrated in the heavy-current transformer (12).

Abstract: The invention relates to a synchronous rectifier (16) for integration into a power source (10) in order to provide a direct current, in particular in a cube or ashlar-shaped unit of a heavy-current transformer (12), comprising circuit elements (24), an actuation circuit (17) for actuating the circuit elements (24) and a supply circuit (48), wherein a printed circuit board (35) with conductor tracks and connection surfaces is provided for receiving electronic components.

Abstract: A heavy-current transformer, in particular for a power source in order to provide a welding current of a resistance welding device, with at least one primary winding and at least one secondary winding with center tapping, and a transformer element, a contact plate and a secondary winding for such a heavy-current transformer as well as a method for the manufacturing thereof, reduce losses and improve efficiency by providing at least four contacts to form a multi-point contacting, the contacts being formed by four contact faces within which the at least one primary winding and the at least one secondary winding are arranged in a series/parallel connection.

Abstract: The invention relates to a method and an apparatus for converting the energy of an energy storage (2) for operating an arc (6), wherein a power unit (3) and an input and/or output device (5) for setting the current for operating the arc (6) is used to convert energy, as well as an appropriate welding device. In order to be able to provide the user with information on the state of energy storage (2), the time remaining for operating the arc (6) using the set current is calculated depending on a determined capacity of the energy storage (2) and a value for the current set on the input and/or output device (5), and said time is displayed on a corresponding display unit (27).

Abstract: The invention relates to a method and an apparatus for converting the energy of an energy storage (2) for operating an arc (6), wherein in order to convert energy, at least one switch (9) of a step-down converter is switched on and off in a controlled manner, wherein said at least one switch (9) is connected to the energy storage (2) at the input end. In order to be able to supply as much of the limited energy available from the energy store (2) to the arc (6), it is provided that a synchronous converter is used as the step-down converter for operating the arc (6), and that the at least one switch (9) of the synchronous converter that is designed as a power unit (3) is connected to a snubber circuit (10) at the output end such that at least the switch (9) is switched on and off in an snubbed state.

Abstract: The invention relates to a method for controlling an inverter and to an inverter a DC/DC stage, which comprises at least one main switch (S2) and a discharge circuit, and with a DC/AC stage. The discharge circuit is formed by a series connection of a bidirectional switching element, which comprises two switches (SA1, SA2), and an inductivity. A device is provided for controlling the switches (SA1, SA2) and is designed such that one switch (SA1, SA2) is activated in an alternating manner and the switch-on time of the switch is determined by the controlling device prior to a switch-off time of the main switch (S2).

Abstract: The invention relates to a synchronous rectifier (16) for integration into a power source (10) in order to provide a direct current, in particular in a cube or ashlar-shaped unit of a heavy-current transformer (12), comprising circuit elements (24), an actuation circuit (17) for actuating the circuit elements (24) and a supply circuit (48), wherein a printed circuit board (35) with conductor tracks and connection surfaces is provided for receiving electronic components.

Abstract: The invention relates to a heavy-current transformer (12), in particular for a power source (10) in order to provide a welding current of a resistance welding device (1), with at least one primary winding (13) and at least one secondary winding (14) with center tapping, and to a transformer element, a contact plate (29) and a secondary winding (14) for such a heavy-current transformer (12) as well as a method for the manufacturing thereof. For reduction of losses and improvement of efficiency, at least four contacts (20, 21, 22, 23) are provided to form a multi-point contacting, said contacts (20, 21, 22, 23) being formed by four contact faces within which the at least one primary winding (13) and the at least one secondary winding (14) are arranged in a series/parallel connection.

Abstract: The invention relates to a resistance welding device (1) comprising a power source (10) in order to provide a welding current for welding workpieces (2, 3), a welding gun (4) with two gun arms (5) comprising one electrode (7) each in order to impress the welding current into the workpieces (2, 3), wherein the power source (10) comprises a heavy-current transformer (12) with at least one primary winding (13) and at least one secondary winding (14) with center tapping, a synchronous rectifier (16) connected with the at least one secondary winding (14) of the heavy-current transformer (12) and comprising circuit elements (24), and a circuit (17) for actuating the circuit elements (24) of the synchronous rectifier (16).