Abstract: A circuit arrangement and a step-down converter have a first and a second input connection, with a first, upper and a second, lower step-down converter element. The first step-down converter element has a first input capacitor, the first capacitor connection of which is connected to the first input connection and the second capacitor connection of which is connected to the second output connection. A first series connection has a first switch and a first diode in parallel with the first input capacitor, and a first coil input of a first coil is connected to the center tap between the first switch and the first diode, the first coil output of said first coil being connected to the first output connection, and wherein the second step-down converter element has a second input capacitor.

Abstract: A current converter circuit arrangement, and a current converter device embodying such arrangement, having positive and negative potential voltage connections, a neutral connection, an AC voltage connection, and first and second inductances. The arrangement further has at least six power semiconductor switches, to each of which a diode is electrically connected back-to-back in parallel, and two further diodes, for a total of eight. The inventive current converter circuit arrangement requires only a low number of power semiconductor switches, at a minimum six, to generate at least five voltage levels at the AC voltage connection.

Abstract: A circuit arrangement for a multilevel power converter comprising a first and second circuit branches, electrically connected in parallel. The arrangement further comprises a positive, negative and neutral potential voltage connections, and first and second AC voltage connections. First circuit branch has controllable first, second and sixth electrical valves and third, fourth and fifth diodes. Second circuit branch has controllable third, fourth and fifth electrical valves and first, second and sixth diodes. In the invention, a power semiconductor switch is connected back-to-back in parallel with a diode provided in a conventional manner in first current branch so that sixth electrical valve is formed, and a power semiconductor switch is connected back-to-back in parallel with a diode provided in a conventional manner in second current branch so that fifth electrical valve is formed. The inventive circuit arrangement has reduced power losses.

Abstract: A DC/DC converter circuit having feedback capability with a first converter device whose two inputs form the inputs of the DC/DC converter circuit and can be connected to a DC voltage source. The DC/DC converter circuit has a DC voltage-coupled second converter device whose outputs form the outputs of the DC/DC converter circuit and can be connected to a DC voltage sink, wherein the second converter device is in the form of a DC/DC converter cell or of a DC/DC converter cell arrangement having two DC/DC converter cells.

Abstract: A circuit having a plurality of parallel-connected partial circuits for feeding an inverter circuit. A partial circuit comprises an unregulated voltage source with a temporally variable output DC voltage and a synchronous converter having an automatically functioning regulating circuit. The circuit is triggered according to two modes of operation. The first mode of operation is as an upward converter, when the value of the output voltage of the unregulated voltage source exceeds a threshold value, and thus the inverter circuit is supplied with the requisite input voltage. The second mode of operation is as a downward converter, when the value of an output voltage of the unregulated voltage source is below a threshold value, or when there is no output voltage from the unregulated voltage source, in which case a first capacitor is charged from the DC voltage applied to the second terminals.

Abstract: A circuit, having a plurality of regulated, parallel, voltage sources, an a.c.-d.c. converter circuit and a regulating unit, and a method for controlling it. The regulated voltage sources include an unregulated voltage source of a temporally variable output d.c. voltage, a step-up converter and an associated regulating device, where the step-up converter is a three-point step-up converter. The regulating unit measures the intermediate circuit voltage of the a.c.-d.c. converter circuit and is connected with the regulating devices. In the method for control, the regulating unit determines the voltage in the intermediate circuit of the a.c.-d.c. converter circuit and from this determines, as a function of the maximally and minimally permissible intermediate circuit voltage, a set-point value for the output voltage of the regulated voltage sources. This set-point value is transmitted to the regulating devices, from which the regulating devices determine the control conditions for the step-up converter.

Abstract: A DC/DC converter circuit having feedback capability with a first converter device whose two inputs form the inputs of the DC/DC converter circuit and can be connected to a DC voltage source. The DC/DC converter circuit has a DC voltage-coupled second converter device whose outputs form the outputs of the DC/DC converter circuit and can be connected to a DC voltage sink, wherein the second converter device is in the form of a DC/DC converter cell or of a DC/DC converter cell arrangement having two DC/DC converter cells.

Abstract: A circuit, having a plurality of regulated, parallel, voltage sources, an a.c.-d.c. converter circuit and a regulating unit, and a method for controlling it. The regulated voltage sources include an unregulated voltage source of a temporally variable output d.c. voltage, a step-up converter and an associated regulating device, where the step-up converter is a three-point step-up converter. The regulating unit measures the intermediate circuit voltage of the a.c.-d.c. converter circuit and is connected with the regulating devices. In the method for control, the regulating unit determines the voltage in the intermediate circuit of the a.c.-d.c. converter circuit and from this determines, as a function of the maximally and minimally permissible intermediate circuit voltage, a set-point value for the output voltage of the regulated voltage sources. This set-point value is transmitted to the regulating devices, from which the regulating devices determine the control conditions for the step-up converter.

Abstract: A circuit having a plurality of parallel-connected partial circuits for feeding an inverter circuit. A partial circuit comprises an unregulated voltage source with a temporally variable output DC voltage and a synchronous converter having an automatically functioning regulating circuit. The circuit is triggered according to two modes of operation. The first mode of operation is as an upward converter, when the value of the output voltage of the unregulated voltage source exceeds a threshold value, and thus the inverter circuit is supplied with the requisite input voltage. The second mode of operation is as a downward converter, when the value of an output voltage of the unregulated voltage source is below a threshold value, or when there is no output voltage from the unregulated voltage source, in which case a first capacitor is charged from the DC voltage applied to the second terminals.