Abstract: The disclosure relates to a platform for the space-saving formation of an energy conversion system. In this, containers are stacked one above the other as housings of components of the energy conversion system with the platform arranged between the containers, wherein the platform has a frame structure which has, on a first side, first alignment elements for placing the platform on a first container and, on a second side, opposite the first side, of the frame structure, second alignment elements for placing a second container on a placement area of the frame structure. The first and second alignment elements are arranged in such a way that they result in an arrangement, which is laterally centered and vertically spaced apart by a height (H) of the platform, of the second container above the first container, wherein the frame structure forms a standing area, which circumferentially surrounds the placement area and is walkable by persons, as access to the second container.

Abstract: The disclosure relates to a power electronics device having at least two inverters and a transformer apparatus having a core arrangement, at least one primary winding and at least one secondary winding that wind around the core arrangement at least in sections.

Abstract: A method for switching off power semiconductor switches in a bridge circuit having first through sixth power semiconductor switches. The method includes a switch-off process for establishing a final switch configuration in which all power semiconductor switches in the bridge circuit are in a switched-off state. Over the course of the switch-off process, a switch configuration is established in which the fifth power semiconductor switch and the sixth power semiconductor switch are concurrently in a switched-on state, while the first power semiconductor switch and the fourth power semiconductor switch are in a switched-off state. Also disclosed is a bridge circuit having a control circuit configured to carry out such a method. In addition, an inverter that includes at least one bridge circuit of this type is also provided.

Abstract: The disclosure relates to a method for determining a characteristic curve for a photovoltaic (PV) string of a photovoltaic system having an inverter which is connected to the photovoltaic string and to a power supply network. The photovoltaic string includes a series connection of a plurality of photovoltaic modules, in which series connection at least one of the photovoltaic modules is integrated into the series connection of the photovoltaic modules via a DC/DC converter. The at least one DC/DC converter operates the photovoltaic module assigned thereto in a first operating mode M1 at a maximum power point by varying, over time, a conversion ratio of output voltage (UOut) to input voltage (UIn), and operates the photovoltaic module in a second operating mode M2 with a conversion ratio of output voltage (UOut) to input voltage (UIn) that is constant over time.

Abstract: A method for three-phase infeed of electrical power from a DC source into a three-phase AC grid by means of an inverter includes measuring phase-specific grid voltages of the three-phase AC grid, and determining a grid frequency from the measured phase-specific grid voltages. The method also includes generating phase-specific voltage reference values from the phase-specifically measured grid voltages and the determined grid frequency, and generating phase-specific target current values using phase-specific predetermined target current amplitude values, the phase-specific voltage reference values and respective grid voltage amplitudes.

Abstract: A method for operating an electrolysis device, having a converter which is connected on an AC voltage side to an AC voltage grid via a decoupling inductance and draws an AC active power from the AC voltage grid, and an electrolyzer, which is connected to the converter on the DC voltage side, is provided. The method includes operating the electrolysis device, when a grid frequency corresponds to a nominal frequency of the ACT voltage grid and is substantially constant over a time period, with an electrical power which is between 50% and 100% of a nominal power of the electrolyzer, and operating the converter in a voltage-impressing manner, such that an AC active power drawn from the AC voltage grid is changed on the basis of a change and/or a rate of change of the grid frequency in the AC voltage grid.

Abstract: A method of detecting a serial arc fault in a DC-power circuit includes injecting an RF-signal with a narrow band-width into the DC-power circuit and measuring a response signal related to the injected RF-signal in the DC-power circuit. The method further includes determining a time derivative of the response signal, analyzing the time derivative, and signaling an occurrence of a serial arc fault in the power circuit based on the results of the analysis. A system for detecting an arc fault is configured to perform a method as described before.

Abstract: The disclosure relates to a method and related device for approximately determining voltages at a high-voltage side of a transformer on the basis of measured voltages at a low-voltage side of the transformer.

Abstract: A battery inverter system includes a plurality of battery inverter units, wherein each of the battery inverter units includes a multiphase inverter and a battery unit connected to the inverter on the DC side. The battery unit includes a plurality of individual units connected in parallel to one another and protected against overcurrent by means of rack fuses, and the battery inverter units are connected in parallel on the AC side and are configured to operate with a common drive pulse pattern. The battery inverter units are interconnected on the DC side via compensation fuses, wherein the compensation fuses are provided such that in the event of a short circuit in one of the inverters, the compensation fuses are triggered faster than the rack fuses.

Abstract: A method for discharging a capacitor of an input or output circuit arrangement of an inverter for supplying current to a power supply grid includes determining voltage readings at connections of the input or output circuit arrangement and a DC link capacitor of the inverter; and calculating an upper limit voltage value of the DC link capacitor based on the measured values. The method also includes operating a DC/DC converter or a bridge arrangement of the inverter such that energy from the capacitor of the input or output circuit arrangement is transferred to the DC link capacitor, ending the method if the voltage across the DC link capacitor exceeds the upper voltage limit. Otherwise the method continues to transfer energy from the capacitor of the input or output circuit arrangement to the DC link capacitor until the capacitor is discharged to or below a lower limit voltage value.

Abstract: A power converter with an inverter that is configured to transform electrical power between a DC-side of the power converter and an AC-side of the power converter, includes a first port operatively connected to an AC-grid, a second port operatively connected to an AC-load, a third port connected to an external power source, and a fourth port operatively connected to a rechargeable DC-power storage. The power converter includes a DC/DC-converter between the third port and the inverter, to transfer electrical power provided by the external power source from the third port to the inverter. The inverter is configured to be grid forming and provide electrical power to the second port upon a power supply outage at the first port, the power converter includes a control unit to monitor the third port and detect parameters of the electrical power provided via the third port.

Abstract: An LC filter arrangement includes a filter capacitor that connects the first output terminal to the second output terminal, a magnetic core, and a choke having a plurality of turns surrounding the magnetic core, and a first choke terminal and a second choke terminal. Each of the turns is formed by a separate conductor segment, at least partially surrounding the magnetic core. The LC filter arrangement is mounted on a circuit board and is electrically connected to a conductor track of the circuit board.

Abstract: A method for regulating a decentralized energy generating system with a plurality of inverters (IN) is disclosed. The method includes receiving at the PPC a detected active power, reactive power and voltage amplitude at a grid connection point (PCC) of the energy generating system; and regulating, in a normal operating mode of the energy generating system, the reactive power and the active power to target values stipulated by a grid operator by virtue of the central control unit (PPC) dividing the stipulated target values into individual target stipulations for the plurality of inverters (IN) and communicating individual target stipulations to the inverters (IN). The method further includes selectively changing to a special operating mode of the energy generating system if particular criteria are present at the grid connection point (PCC) in a stipulated time interval.

Abstract: A photovoltaic energy generation system with a string including a series connection of solar modules, which string is electrically connected to an inverter via power lines for converting and feeding electrical power from the string into a network. The inverter is configured to obtain an alternative operating power from only one of the solar modules in the event that normal operating power can be obtained neither from the network nor from the entire string. A supply line can supply the alternative operating power to the inverter. Furthermore, the connectors and mating connectors of such a supply line are described, which can also be installed with an inverter.

Abstract: To operate electrical devices, power consumptions of all the electrical devices are continually captured and assigned to the individual electrical devices and at least one desired result is achieved by virtue of at least a first control instance of the electrical devices, the operation of which helps to achieve a desired result, and a second control instance of the electrical devices, the operation of which likewise helps to achieve the desired result. The devices are operated in a coordinated fashion. To this end, measured values from multiple measured value transmitters are captured by operating the multiple electrical devices. Correlations between changes in the measured values of the individual measured value transmitters over time and changes in the power consumptions of the individual electrical devices over time are determined and the desired result is selected from a subgroup of results.

Abstract: An energy generation system provides balancing power for an AC voltage grid, and comprises a photovoltaic generator and an energy store, wherein the energy generation system exchanges a total electrical power with the AC voltage grid (1), wherein the total power exchanged is set as a function of a current maximum PV power, a predefinable basic PV power between zero and the maximum PV power and a provided or requested balancing power. When no balancing power is requested: a total basic power, which comprises the basic PV power can be fed in; When a negative balancing power is requested: the PV power can be reduced compared to the basic PV power; When a positive balancing power is requested: a battery power can be drawn from the energy store if the requested positive balancing power is greater than the difference between the maximum PV power and the basic PV power.

Abstract: A method provides current limitation in the event of transient voltage variations at an AC output of a multilevel inverter that includes a bridge circuit with a first DC input, a second DC input, a neutral terminal and a bridge output, as well as a line filter with a choke connected between the bridge output and the AC output, and a capacitor connected between the AC output and the neutral terminal. In the method, depending on the voltage at the capacitor, when a first current threshold is exceeded by the choke current, a regular operating mode is interrupted and measures for current limitation are initiated. A multilevel inverter is further disclosed including a control circuit that is configured to carry out such a method.

Abstract: A relay arrangement includes at least two series-connected relays, which are mechanically and electrically connected to a main printed circuit board via first terminals and second terminals, and at least one flat conductor for conducting current between the at least two series connected relays. The flat conductor is mechanically connected to the main printed circuit board and electrically and thermally connected to the first terminals of the relays, and the at least one flat conductor is configured to dissipate heat produced during operation of the relays.

Abstract: A method of detecting a serial arc fault in a DC-power circuit includes injecting an RF-signal with a narrow band-width into the DC-power circuit and measuring a response signal related to the injected RF-signal in the DC-power circuit. The method further includes determining a time derivative of the response signal, analyzing the time derivative, and signaling an occurrence of a serial arc fault in the power circuit based on the results of the analysis. A system for detecting an arc fault is configured to perform a method as described before.

Abstract: A method for controlling an electrical power which flows into or out of an electrical subnetwork via a connection point is disclosed. The subnetwork has at least one electrical load, and the electrical load is connected to a control device via a communication connection, the electrical power flowing via the connection point is measured and a maximum power consumption of the electrical load is set by means of the control device on the basis of the electrical power flowing via the connection point. A device for connecting a multiphase subnetwork, which has an energy production installation and an energy store, to a superordinate multiphase alternating voltage network is configured to transmit electrical power between the alternating voltage network and the subnetwork and comprises an AC/AC converter having a network connection, two inverter bridge circuits with an interposed intermediate circuit and a subnetwork connection.