Abstract: The present disclosure relates to a power grid including a converting stage including a plurality of DC/DC converters connected in parallel. At least one of the DC/DC converters is a single-stage isolated DC/DC converter including a voltage control configured to control a voltage of the respective DC/DC converter.

Abstract: A transformer arrangement includes a first and a second arrangement side and a transformer with first windings coupled to the first arrangement side and with second windings having a first to a fourth tap. The transformer arrangement comprises a converter coupling the first, second and third tap to the second arrangement side, a first filter circuit coupling the first tap to the third tap and a second filter circuit coupling the third tap to the second tap.

Abstract: The disclosure relates to a power grid, comprising a converting stage comprising a plurality of DC/DC converters. At least one of the DC/DC converters is a single-stage isolated DC/DC converter comprising a voltage control configured to control a voltage of the respective DC/DC converter. The DC/DC converters are connected in series and at least one of the plurality of converters of the converting stage is configured to provide a respective predetermined output voltage to a load.

Abstract: Unique systems, methods, techniques and apparatuses of hybrid power plants are disclosed. One exemplary embodiment is a hybrid power plant system including a plurality of hybrid generation units each including an AC collection bus, an AC power source, an AC-AC power converter coupled to the AC power source and AC collection bus, a DC power source, a DC-AC converter coupled to the DC power source and the AC collection bus, an energy storage device, and a power transformer coupled to the AC collection bus and structured to receive AC power from the AC collection bus, step up a voltage of the received AC power, and output medium voltage AC (MVAC) power.

Abstract: Systems, methods, techniques and apparatuses of fault protection. One exemplary embodiment is a protection system including a solid-state switching device, a galvanic isolation switching device, and a controller. The solid-state switching device is coupled between a switch arrangement of a power converter and a direct current (DC) link capacitor of the power converter. The galvanic isolation switching device is coupled between the DC link capacitor and a DC network. The controller is structured to determine a fault is occurring within the DC network, open the solid-state switching device in response to determining the fault is occurring, receive a measurement corresponding to an electrical characteristic of a fault current flowing through the galvanic isolation switching device while the solid-state switching device is open, and determine a location of the fault based on the received measurement.

Abstract: Unique systems, methods, techniques and apparatuses of hybrid power plants are disclosed. One exemplary embodiment is a hybrid power plant system including a plurality of hybrid generation units each including an AC collection bus, an AC power source, an AC-AC power converter coupled to the AC power source and AC collection bus, a DC power source, a DC-AC converter coupled to the DC power source and the AC collection bus, an energy storage device, and a power transformer coupled to the AC collection bus and structured to receive AC power from the AC collection bus, step up a voltage of the received AC power, and output medium voltage AC (MVAC) power.

Abstract: Unique systems, methods, techniques and apparatuses of a power collection system are disclosed herein. One exemplary embodiment is an MVDC collection system coupled to a utility grid including a collection bus, a plurality of branches coupled to the collection bus, and a branch controller. Each of the plurality of branches include a semiconductor switch coupled to the collection bus, and a DC/DC converter coupled to the semiconductor switch and an LVDC power source. The branch controller configured to determine a fault condition is occurring within the MVDC collection system, determine the location of the fault condition, and isolate the fault condition using at least one of the semiconductor switches and the DC/DC converters.

Abstract: A semiconductor stack for a converter comprises two series-connected semiconductor switches; two terminals for connecting a cell capacitor, which are connected to one another by the two semiconductor switches; at least one cooling element arranged between the semiconductor switches; a frame, by which the semiconductor switches and the cooling element are fixed to one another and which provides the terminals; and at least two snubber capacitors which are mechanically fixed to the frame and which are connected in parallel, are connected to the terminals and which in each case form a commutation loop with the semiconductor switches.

Abstract: Unique systems, methods, techniques and apparatuses of a power collection system are disclosed herein. One exemplary embodiment is an MVDC collection system coupled to a utility grid including a collection bus, a plurality of branches coupled to the collection bus, and a branch controller. Each of the plurality of branches include a semiconductor switch coupled to the collection bus, and a DC/DC converter coupled to the semiconductor switch and an LVDC power source. The branch controller configured to determine a fault condition is occurring within the MVDC collection system, determine the location of the fault condition, and isolate the fault condition using at least one of the semiconductor switches and the DC/DC converters.

Abstract: A converter comprises a first inverter for converting a first multi-phase AC voltage into a DC voltage and a second inverter for converting the DC voltage into a second multi-phase AC voltage. A method for controlling the electrical converter comprises: switching the first inverter such that a first common mode voltage is generated in the first multi-phase AC voltage; switching the second inverter such that a second common mode voltage is generated in the second multi-phase AC voltage, wherein the first common mode voltage and the second common mode voltage are synchronized such that the first common mode voltage and the second common mode voltage cancel each other at least partially.

Abstract: A converter arrangement comprises first and second modular multilevel converters, Each of the modular multilevel converters comprises two converter branches. Each converter branch comprises a plurality of series-connected converter cells. Each converter cell comprises a cell capacitor and semiconductor switches for connecting and disconnecting the cell capacitor to the converter branch. At least two converter branches of the first modular multilevel converter are connected via first branch connection point and at least two converter branches of the second modular multilevel converter are connected via second branch connection point. The multilevel converters are connected in parallel via a phase connection point for connecting the converter arrangement to a load or a power source, wherein the phase connection point is connected via a first inductance with the first branch connection point and/or via a second inductance with the second branch connection point.

Abstract: A power plant, and a method for using an electrical unit therefor are disclosed, wherein, an electrical machine can be connected to a power network via a converter and a block transformer. A method is disclosed for using the electrical unit, wherein the converter disconnects the block transformer from the machine in the event of a malfunction of the block transformer.

Abstract: A converter comprises a first inverter for converting a first multi-phase AC voltage into a DC voltage and a second inverter for converting the DC voltage into a second multi-phase AC voltage. A method for controlling the electrical converter comprises: switching the first inverter such that a first common mode voltage is generated in the first multi-phase AC voltage; switching the second inverter such that a second common mode voltage is generated in the second multi-phase AC voltage, wherein the first common mode voltage and the second common mode voltage are synchronized such that the first common mode voltage and the second common mode voltage cancel each other at least partially.

Abstract: A semiconductor stack for a converter comprises two series-connected semiconductor switches; two terminals for connecting a cell capacitor, which are connected to one another by the two semiconductor switches; at least one cooling element arranged between the semiconductor switches; a frame, by which the semiconductor switches and the cooling element are fixed to one another and which provides the terminals; and at least two snubber capacitors which are mechanically fixed to the frame and which are connected in parallel, are connected to the terminals and which in each case form a commutation loop with the semiconductor switches.

Abstract: The invention relates to a pumped storage power plant, in particular to an electric unit 1 comprising a converter 3, a rotating electric synchronous machine 4 and a charging unit 5, wherein the charging unit 5 has at least one transformer 6 and one switch 7 and can be connected to a supply grid 2, on the one hand, and to the converter 3, on the other. The invention also relates to a method for using the electric unit 1 comprising at least opening a generator switch 15 in order to disconnect the synchronous machine 4 from the converter 3; charging cells of the converter 3 which have capacitors and/or accumulators by closing a switch 7 of the charging unit 5, wherein by closing the switch 7 the converter 3 is connected to the supply grid 2 via the transformer 6 of the charging unit 5; opening the switch 7 of the charging unit 5 after the complete charging of the converter 3; and closing the generator switch 15 in order to connect the synchronous machine 4 to the converter 3 and/or the secondary line 11.

Abstract: A converter arrangement comprises first and second modular multilevel converters, Each of the modular multilevel converters comprises two converter branches. Each converter branch comprises a plurality of series-connected converter cells. Each converter cell comprises a cell capacitor and semiconductor switches for connecting and disconnecting the cell capacitor to the converter branch. At least two converter branches of the first modular multilevel converter are connected via first branch connection point and at least two converter branches of the second modular multilevel converter are connected via second branch connection point. The multilevel converters are connected in parallel via a phase connection point for connecting the converter arrangement to a load or a power source, wherein the phase connection point is connected via a first inductance with the first branch connection point and/or via a second inductance with the second branch connection point.

Abstract: A pumped-storage power plant is disclosed, such as an electric unit having a converter and a rotating electric synchronous machine. The converter is designed as a modular multilevel converter and the machine is directly connectable to the converter, wherein the converter has an adjustable voltage.

Abstract: An energy generation system includes a turbine, an electric generator, a step-up transformer, and a converter. The turbine is operable to extract energy from a fluid flow and convert the extracted energy into mechanical energy. The electric generator is operable to convert the mechanical energy from the turbine into AC electrical energy. The step-up transformer is operable to transfer the AC electrical energy at a lower voltage from the electric generator to a higher voltage. The converter is operable to convert the AC electrical energy at the higher voltage to DC electrical energy. The converter includes a converter leg for a phase of the AC electrical energy. The converter leg has an upper arm with a first plurality of sub-modules and a lower arm with a second plurality of sub-modules. Each sub-module is operable to function as a controlled voltage source.

Abstract: A power plant, and a method for using an electrical unit therefor are disclosed, wherein, an electrical machine can be connected to a power network via a converter and a block transformer. A method is disclosed for using the electrical unit, wherein the converter disconnects the block transformer from the machine in the event of a malfunction of the block transformer.

Abstract: An energy generation system includes a turbine, an electric generator, a step-up transformer, and a converter. The turbine is operable to extract energy from a fluid flow and convert the extracted energy into mechanical energy. The electric generator is operable to convert the mechanical energy from the turbine into AC electrical energy. The step-up transformer is operable to transfer the AC electrical energy at a lower voltage from the electric generator to a higher voltage. The converter is operable to convert the AC electrical energy at the higher voltage to DC electrical energy. The converter includes a converter leg for a phase of the AC electrical energy. The converter leg has an upper arm with a first plurality of sub-modules and a lower arm with a second plurality of sub-modules. Each sub-module is operable to function as a controlled voltage source.