Abstract: A dual submodule is created for a modular multilevel converter, whereby the dual submodule has two interconnected submodules, whereby each submodule has an asymmetrical half-bridge circuit with two parallel bridge branches, which are connected between a first and a second terminal connection of the submodule, whereby each bridge branch is formed from a series circuit of a power semiconductor switch, and a diode, whereby the power semiconductor switch is allocated to an antiparallel free-wheeling diode, and has a capacitor, which is connected in parallel with the asymmetrical half-bridge circuit between the first and the second terminal connections of the module. The submodules are connected to each other via their AC terminals to form the dual submodule. Further, a modular multilevel converter is created, comprising a number of such dual submodules in each of its converter branches.

Abstract: A double submodule for a modular multilevel converter comprising a first and second submodule coupled to the first. Each submodule comprises an asymmetric H bridge circuit with two parallel bridges branches, connected between a first and a second direct voltage node of the submodule. Each bridge branch is formed by a series connection from a controllable power semiconductor switch and a diode. A storage capacitor is connected in parallel to the asymmetric H bridge circuit between the first and the second direct voltage node of the submodule. The first and the second submodule are interconnected in such a way that a power semiconductor switch or a diode is part of a bridge branch of the first submodule as well as part of a bridge branch of the second submodule. A modular multilevel converter, comprises a series connection of such double submodules in each of its converter branches, is also disclosed.

Abstract: A dual submodule is created for a modular multilevel converter, whereby the dual submodule has two interconnected submodules, whereby each submodule has an asymmetrical half-bridge circuit with two parallel bridge branches, which are connected between a first and a second terminal connection of the submodule, whereby each bridge branch is formed from a series circuit of a power semiconductor switch, and a diode, whereby the power semiconductor switch is allocated to an antiparallel free-wheeling diode, and has a capacitor, which is connected in parallel with the asymmetrical half-bridge circuit between the first and the second terminal connections of the module. The submodules are connected to each other via their AC terminals to form the dual submodule. Further, a modular multilevel converter is created, comprising a number of such dual submodules in each of its converter branches.

Abstract: A double submodule for a modular multilevel converter comprising a first and second submodule coupled to the first. Each submodule comprises an asymmetric H bridge circuit with two parallel bridges branches, connected between a first and a second direct voltage node of the submodule. Each bridge branch is formed by a series connection from a controllable power semiconductor switch and a diode. A storage capacitor is connected in parallel to the asymmetric H bridge circuit between the first and the second direct voltage node of the submodule. The first and the second submodule are interconnected in such a way that a power semiconductor switch or a diode is part of a bridge branch of the first submodule as well as part of a bridge branch of the second submodule. A modular multilevel converter, comprises a series connection of such double submodules in each of its converter branches, is also disclosed.

Abstract: A short-circuit device and a protection method for a submodule for a power converter are disclosed. The submodule includes a bridge circuit having at least one power semiconductor branch extending between a first and a second DC voltage node and at least one controllable power semiconductor switch disposed therein to which a freewheeling diode is connected in anti-parallel, and a capacitor connected in parallel to the bridge circuit. The short-circuit device has at least one selected of the freewheeling diodes anti-parallel to the power semiconductor switches of the bridge circuit, wherein the at least one selected freewheeling diode is manufactured in press pack design and rated such that, when a fault occurs in the submodule, the at least one selected freewheeling diode breaks down due to the fault conditions and provides a durable, stable, low-impedance short circuit path between a first and a second AC voltage connection of the submodule.

Abstract: Described is a circuit for converting electric power between a three-phase grid and a single-phase grid. The circuit includes, in at least one embodiment, a first transformer that is connected to the three-phase grid, a number of first converter stages assigned to the first transformer, the associated DC intermediate circuits and the associated second converter stages. The second converter stages are connected to each other at the alternating-current side outputs with the aid of a series connection.

Abstract: A short-circuit device and a protection method for a submodule for a power converter are disclosed. The submodule includes a bridge circuit having at least one power semiconductor branch extending between a first and a second DC voltage node and at least one controllable power semiconductor switch disposed therein to which a freewheeling diode is connected in anti-parallel, and a capacitor connected in parallel to the bridge circuit. The short-circuit device has at least one selected of the freewheeling diodes anti-parallel to the power semiconductor switches of the bridge circuit, wherein the at least one selected freewheeling diode is manufactured in press pack design and rated such that, when a fault occurs in the submodule, the at least one selected freewheeling diode breaks down due to the fault conditions and provides a durable, stable, low-impedance short circuit path between a first and a second AC voltage connection of the submodule.

Abstract: A method for operating an electrical circuit is described herein. The circuit includes a power converter having a plurality of switches and two capacitors that are parallel to the switches. The plurality of switches and the two capacitors are connected in series. The power converter has two AC voltage-sided connections and a measuring resistor is connected to the ground. A ground fault is detected by measuring a voltage drop in a measuring resistor.

Abstract: Described is a modular switch for an electrical converter. The modular switch is provided with a first series circuit including a first controllable power semiconductor component and a first diode as well as with a second series circuit including a second diode and a second controllable power semiconductor. The connecting point between the first power semiconductor component and the first diode forms a first terminal and the connecting point between the second diode and the second power semiconductor component forms a second terminal of the modular switch. Also provided is a capacitor, wherein the first series circuit and the second series circuit and the capacitor are switched parallel to each other.

Abstract: An electrical frequency converter for coupling an electrical power supply grid with an electrical drive includes a first power converter connected to the power supply grid. The first power converter includes at least two connections in series. A second power converter is connected to the electrical drive and includes at least two connections in series. Each of the connections in series of the first and second power converters includes at least two modular switches. Each modular switch includes a first connection in series having a first controllable power semiconductor component and a first diode. The modular switch further includes a second connection in series having a second controllable power semiconductor component and a second diode. The modular switch further includes a capacitor. The first connection in series, the second connection in series and the capacitor are connected in parallel.

Abstract: Described is a method for testing a power producer or a power consumer that can be connected to a power grid. The power producer or the power consumer is connected to a terminal point. A converter circuit is provided for influencing a voltage that is present at the terminal point. The converter circuit is connected via a transformer to the terminal point. In at least one embodiment, a series connection is configured with a choking coil and a first switch and connected to the terminal point. In a time coordinated manner, the first switch is initially closed and the converter circuit is influenced such that the voltage has the desired value at the terminal point, whereupon the second switch is then opened.

Abstract: A method for operating an electrical circuit including a modular switch with four power semiconductor components and one capacitor. With this method, either both the first and the second power semiconductor components are switched so as to be conducting, and both the third and the fourth power semiconductor components are controlled so as to be blocking, so that a current flows from the first connection across the first power semiconductor component, across the capacitor and across the second power semiconductor component to the second connection, or both the third and fourth power semiconductor components are switched so as to be conducting, and both the first and the second power semiconductor components are controlled so as to be blocking, so that the current flows in reverse direction from the second connection across the fourth power semiconductor component, across the capacitor and across the third power semiconductor component to the first connection.

Abstract: A method for operating an electrical circuit is described herein. The circuit includes a power converter having a plurality of switches and two capacitors that are parallel to the switches. The plurality of switches and the two capacitors are connected in series. The power converter has two AC voltage-sided connections and a measuring resistor is connected to the ground. A ground fault is detected by measuring a voltage drop in a measuring resistor.

Abstract: Electrical frequency converter (20) for coupling an electrical power supply grid (21) with an electrical drive (22) is described. One rectifier (23) and one inverter (24) are provided, in which case the rectifier (23) is connected to the power supply grid (21) and the inverter (24) to the drive (22). The rectifier (23) and the inverter (24) have in each case at least two connections in series (25), and every one of the connections in series (25) has at least two modular switches (10).

Abstract: Described is an electric circuit which is intended, in particular, for the testing of a power producer in a wind power plant. The power producer is connected to a terminal point and is provided with a converter circuit which can be used to influence a voltage that is present at the terminal point. Also provided is a series connection configured with a choke coil and a first switch and connected to the terminal point. In at least one embodiment, a control and/or regulating system is provided for influencing, in a time-synchronized manner, on the one hand the converter circuit, such that the voltage at the terminal point transitions to a desired value and, on the other hand, the closing of the first switch.

Abstract: Described is a circuit for converting electric power between a three-phase grid and a single-phase grid. The circuit includes, in at least one embodiment, a first transformer that is connected to the three-phase grid, a number of first converter stages assigned to the first transformer, the associated DC intermediate circuits and the associated second converter stages. The second converter stages are connected to each other at the alternating-current side outputs with the aid of a series connection.

Abstract: Described is a method for testing a power producer or a power consumer that can be connected to a power grid. The power producer or the power consumer is connected to a terminal point. A converter circuit is provided for influencing a voltage that is present at the terminal point. The converter circuit is connected via a transformer to the terminal point. In at least one embodiment, a series connection is configured with a choking coil and a first switch and connected to the terminal point. In a time coordinated manner, the first switch is initially closed and the converter circuit is influenced such that the voltage has the desired value at the terminal point, whereupon the second switch is then opened.

Abstract: Described is a modular switch for an electrical converter. The modular switch is provided with a first series circuit including a first controllable power semiconductor component and a first diode as well as with a second series circuit including a second diode and a second controllable power semiconductor. The connecting point between the first power semiconductor component and the first diode forms a first terminal and the connecting point between the second diode and the second power semiconductor component forms a second terminal of the modular switch. Also provided is a capacitor, wherein the first series circuit and the second series circuit and the capacitor are switched parallel to each other.

Abstract: Described is an electric circuit which is intended, in particular, for the testing of a power producer in a wind power plant. The power producer is connected to a terminal point and is provided with a converter circuit which can be used to influence a voltage that is present at the terminal point. Also provided is a series connection configured with a choke coil and a first switch and connected to the terminal point. In at least one embodiment, a control and/or regulating system is provided for influencing, in a time-synchronized manner, on the one hand the converter circuit, such that the voltage at the terminal point transitions to a desired value and, on the other hand, the closing of the first switch.