Abstract: The disclosure is a method for operating an inverter with a DC input and an AC output. The DC input is connected to a DC source, bridge branches of a bridge circuit are connected to the AC output via power chokes, and the AC output is connected to an AC grid via isolating switches. The method includes opening the isolating switches, and controlling semiconductor switches of at least two bridge branches of the bridge circuit that are connected downstream of at least one power choke at the AC side, such that a DC source connected to the DC input is loaded. The sum of the currents flowing out of at least one of the at least two bridge branches on the AC side corresponds to the sum of the currents flowing into at least one other bridge branch of the at least two bridge branches on the AC side.

Abstract: The disclosure relates to a method for operating an energy supply system, wherein a first and a second DC unit exchange power with an AC bus using a first and a second power converter. With transmission using a transformer, this power is combined and converted using a third power converter into a DC grid power of a DC grid and/or vice versa.

Abstract: A method for starting an electrolysis system is disclosed. A supply circuit has an AC terminal connected to an AC grid, a DC terminal connected to an electrolyzer, and an AC/DC converter arranged between the AC terminal and the DC terminal. The method includes charging an output capacitor connected to a DC converter terminal of the AC/DC converter, by operating the electrolyzer in a reverse mode, while the AC/DC converter is connected to the electrolyzer and disconnected from the AC grid, connecting the AC/DC converter to the AC grid, reversing the operation of the electrolyzer from the reverse mode to a normal mode as a DC load, to suppress a power flow between the AC grid and the electrolyzer, and operating the electrolyzer in the normal mode with electrical power drawn from the AC grid which is rectified by the AC/DC converter.

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: The application describes operating an inverter having an AC connection, a DC connection and an inverter bridge therebetween. The operation includes operating the inverter in a first mode in which, at the AC connection, an AC grid is supplied with electrical power via the inverter, and the voltage of the AC grid is controlled via a regulation of the inverter. If an increase in a current at the AC connection exceeds a current limit value: changing to a second mode and operating the inverter, wherein a regulation is adapted such that, via a virtual impedance, it limits the current at the AC connection.

Abstract: A power converter between an AC side and DC of the power converter is disclosed. The AC side is connected to an AC supply grid and the DC side is connected to a DC grid. The power converter includes a bridge circuit connected to the AC side of the power converter via AC switches and connected to the DC side of the power converter via circuit breakers, wherein a DC link circuit of the power converter is chargeable from the AC supply grid via an AC precharging circuit. The power converter has an insulation monitor to measure the insulation resistance of the DC side when the AC precharging circuit is connected to the DC link circuit. The disclosure also includes a related method.

Abstract: The application describes a method for balancing voltages on a first and a second DC conductor in a DC grid using a balancing circuit with a first and second semiconductor switch connected in series between the first and second DC conductors, and a connection to a ground potential that is arranged between the first and second semiconductor switches. In the presence of an asymmetry in the voltages of the first and second DC conductors to ground potential, a compensation current is generated between at least one of the DC conductors ground potential via at least one of the semiconductor switches, with the asymmetry in the voltages being reduced by the compensation current (IA), with the voltages of the DC conductors to ground potential being balanced.

Abstract: An electrical system includes a power converter and a DC/DC converter configured to transfer power between an AC side and a DC side thereof. The AC side is connected to an AC supply grid and the DC side is connected to a DC grid. The power converter has a bridge circuit connected to the AC side of the power converter via AC relays and connected to the DC side of the power converter via circuit breakers. A measuring device measures a DC power converter voltage and a DC/DC output voltage present on the output side of the DC/DC converter. A control circuit is configured to drive the DC/DC converter. The application also describes a method for operating an electrical system.

Abstract: A described method for operating a battery converter in a system, in which, in addition to the battery converter, an inverter, which is connected to a grid, and a DC load are connected to a common intermediate circuit via a DC bus, includes: —controlling an exchange power of the battery converter using a battery, which is connected to the battery converter, depending on a voltage of the intermediate circuit in accordance with a converter characteristic curve, —identifying a decrease in the intermediate circuit voltage below a rectifying value of the permissible AC voltage of the grid connected to the inverter, and —if the decrease is identified, temporarily shifting the converter characteristic curve so that a maximum discharging power of the battery converter is reached at a value of the intermediate circuit voltage that is above or at the rectifying value. A battery converter, which is configured to carry out the method, and a system having such a battery converter are also described.

Abstract: The disclosure relates to an inverter including a first bridge branch with a first phase output, a second bridge branch with a second phase output, a third bridge branch with a third phase output, wherein the phase outputs of the bridge branches can each be connected to a phase conductor of a three-phase power distribution network.

Abstract: A method and related apparatus for extending a DC voltage range of a rectifier circuit for the supply, from an AC grid, of a DC load which is connected to a DC rectifier output of the rectifier circuit, wherein an AC rectifier input of the rectifier circuit is connected via a grid connection point to the AC grid, wherein the rectifier circuit includes an AC/DC converter having an AC input and a DC output, wherein the AC/DC converter includes a converter circuit having semiconductor switches and freewheeling diodes connected in an antiparallel arrangement thereto, wherein an inductance is connected between the AC input of the AC/DC converter and the grid connection point.

Abstract: The application describes a method for operating an electrolyzer to generate hydrogen from water using an electrolysis reaction, supplied with power from an AC grid via an actively controlled rectifier circuit. The method includes operating the electrolyzer in a normal operating mode with an input voltage UEI above a no-load voltage ULL with predominantly ohmic behavior, operating the electrolyzer in a standby operating mode with an input voltage UEI below the no-load voltage ULL with predominantly capacitive behavior, and transitioning from the standby operating mode to the normal operating mode during a first transition duration ?t1, wherein the first transition duration ?t1 is reduced by keeping the input voltage UEI at the electrolyzer input during the standby operating mode above a first voltage threshold value UTH,1 different from 0 V. The application furthermore describes a connection circuit, an actively controlled rectifier circuit and an electrolysis system for performing the method.

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.

Abstract: The disclosure is directed to a method for supplying power to a DC load using an energy conversion system that includes first and second rectifiers and a transformer system. Each of the rectifiers contains an AC-DC converter connected to an AC grid via a separate secondary side of the transformer system. The transformer system provides a first AC voltage having a first voltage amplitude Û1 on the first secondary side and a second AC voltage having a second voltage amplitude Û2 on the second secondary side, wherein a value of the second voltage amplitude Û2 exceeds a corresponding value of the first voltage amplitude Û1.

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 is disclosed for controlling an electrical installation having electrical devices operated in an energy-producing, energy-storing and/or energy-consuming manner and are connected to an energy supply grid. The method includes a first stage which is aimed at achieving an installation target PAnl,Soll for a power flow PAnl assigned to the installation at the grid connection point, and a second stage which is aimed at achieving an individual device target PGer,Soll,i for a power flow PGer,i of each device from the plurality of devices. On the basis of detection of a power flow PAnl of the installation at a grid connection point and a comparison of the detected power flow PAnl of the installation with the installation target PAnl,Soll, the installation is operated in the second stage if the detected power flow PAnl of the installation is within a tolerance range around the installation target PAnl,soll, or is otherwise operated in the first stage.

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.

Abstract: A method and corresponding system for operating an inverter includes setting an input voltage (UPV) of the inverter by an input-side DC-DC converter and/or an output-side inverter bridge, wherein the input voltage (UPV) corresponds to an MPP voltage (UMPP) at which a generator connectable on the input side outputs a maximum electrical power, and determining a first temperature value (TDCDC) in the DC-DC converter and a second temperature value (TDCAC) in the inverter bridge.

Abstract: A method for determining capacitance values of capacitances of a photovoltaic system including a multiphase inverter which includes an output current filter on an alternating current side thereof and is connected to a multiphase energy supply network via a switching element and is associated with at least one intermediate circuit capacitance on the direct current side thereof is provided.

Abstract: In order to distribute power over multiple direct current sources which are connected in parallel to an input-side direct voltage intermediate circuit of a DC/AC transformer, at least one of which direct current sources is connected to the direct voltage intermediate circuit via a DC/DC transformer, wherein the DC/DC transformer can be actuated to change the power fed into the direct voltage intermediate circuit by the direct current source, the power levels of the direct current sources are decreased differently in a decreased operating mode of the DC/AC transformer in which the power of the DC/AC transformer is decreased compared to the sum of the maximum power levels available from all the direct current sources, and by actuating at least the one DC/DC transformer via which the at least one direct current source is connected to the direct voltage intermediate circuit, variation in the power levels of at least one other direct current source is compensated dynamically.