Sma Solar Technology Ag

Alexander Unru

Marcel Kratochvil

Burkard Müller

Tobias Mueller

Martin Bock

Andreas Falk

Claus Allert

Matthias Groene

Dirk Hermeling

Pablo Ignacio Correa Vasquez

Mathias Buenemann

Sybille Pape

Ralf Juchem

Harald Drangmeister

Thomas Schroeder

Neidhardt Bechtel

Tobias Müller

Moritz Welker

Thomas Ortmann

Thomas SCHRÖDER

Tobias MÜLLER

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.

Power converter for transferring power between an AC side and a DC side, and power supply method

A device for converting electrical power between a PV generator and an electrolyzer. The device has an inverter arranged between a first side thereof and a transformer, and an active rectifier is arranged between the transformer and a second side of the device, such that an AC side of the active rectifier and an AC side of the inverter are connected to one another via the transformer. The inverter is configured to convert a first DC voltage on the DC side of the inverter into a first AC voltage on the AC side of the inverter and the active rectifier is configured designed to convert a second AC voltage on the AC side of the active rectifier into a second DC voltage on the DC side of the active rectifier. The device has a controller configured to influence a power flow between the first side and the second side of the device from a connected PV generator to a connected electrolyzer by adjusting an AC/DC transformation ratio of the active rectifier between the second AC voltage and the second DC voltage.

Device and method for converting electrical energy

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. The method includes setting a desired DC operating voltage Uon the DC output of the AC/DC converter or on the DC rectifier output, or both, by an actuation of semiconductor switches of the AC/DC converter, wherein, when the desired DC operating voltage Ulies below a value of an amplitude Ûof an alternating voltage on the AC input of the AC/DC converter, the semiconductor switches of the AC/DC converter are actuated for an exchange of reactive power Q(t) with the AC grid, which has a voltage-lowering effect upon the amplitude Ûof the AC voltage at the AC input of the AC/DC converter, such that the amplitude Ûapproaches the desired DC operating voltage U, and wherein the exchange of the reactive power Q(t) with the AC grid is executed during or shortly before an electrical connection or an electrical isolation of the DC load to or from the rectifier circuit.

Method for extending a voltage range of a rectifier, rectifier for carrying out the method, and electrolysis system

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.

Method for operating a DC voltage grid and power converter for connecting a DC voltage grid to an AC voltage grid

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.

Method for operating an energy supply system, device for exchanging electrical power in an energy supply system, and energy supply system

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.

Method for balancing voltages in a DC grid and balancing unit for a DC grid

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. The inverter is configured, in a normal operating mode of the three-phase power distribution network and/or of a higher-level power supply network connected thereto, to connect the phase outputs to the relevant phase conductor and, in the event of a fault in the three-phase power distribution network and/or in the higher-level power supply network connected thereto, to disconnect the three-phase power distribution network from the higher-level power supply network via a network disconnector, to disconnect the first phase output from the first phase conductor by means of a switching unit and to connect same to a neutral conductor of the three-phase power distribution network, and to establish a neutral potential for the neutral conductor via the first bridge branch. The disclosure further relates to a method for operating an inverter of this kind.

3-phase PV inverter with 2-phase isolated operation in the event of a network fault

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.

Method for operating a battery converter, battery converter and system

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.

Method for three-phase supply into an alternating voltage network, and three-phase inverter

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. The device also comprises a control device which is configured to set the electrical powers flowing via the individual phases of the subnetwork connection on the basis of power values of the energy production installation and/or of the energy store by suitably controlling the inverter bridge circuits of the AC/AC converter.

Device for connecting a sub-network to an alternating voltage network and method for controlling an electrical power

A method and corresponding system for operating an inverter includes setting an input voltage (U) of the inverter by an input-side DC-DC converter and/or an output-side inverter bridge, wherein the input voltage (U) corresponds to an MPP voltage (U) at which a generator connectable on the input side outputs a maximum electrical power, and determining a first temperature value (T) in the DC-DC converter and a second temperature value (T) in the inverter bridge. The method or corresponding system further includes changing the input voltage (U) of the inverter with respect to the MPP voltage (U) if at least one of the determined temperature values (T, T) exceeds a limit value (T, T) assigned to the respective temperature values (T, T), increasing the input voltage (U) with respect to the MPP voltage (U) if an exceedance of the limit value (T) for the first temperature value (T) in the DC-DC converter is determined and/or the MPP voltage (U) lies below a predefined limit voltage (U), and otherwise reducing the input voltage (U) ith respect to the MPP voltage (U).

Photovoltaic inverter comprising an upstream DC/DC converter and temperature regulation of the power semiconductors

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. The method includes disconnecting the photovoltaic system from the energy supply network by opening the switching element; operating the inverter to set up an island network after the disconnecting, wherein an in-phase AC voltage is applied to at least two outputs of an inverter bridge of the multiphase inverter and a flow of current is produced between the at least one intermediate circuit capacitance and at least one filter capacitance of the output current filter; measuring currents (Ia, Ib, Ic) flowing at the outputs of the inverter bridge and at least one voltage present at one of the capacitances, and determining a capacitance value of at least one of the capacitances using the determined voltage and the measured currents (Ia, Ib, Ic).

Method and inverter for determining capacitance values of capacitances of an energy supply system

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.

Method and inverter for distributing power among a plurality of DC sources connected jointly to a DC voltage input of a DC-to-AC converter

The disclosure relates to a tracking method for a voltage transformer, in particular an inverter, of a photovoltaic system. In the method, an intermediate circuit voltage is repeatedly decreased or increased in one direction to a lower or higher voltage by voltage steps of a specified magnitude. The method is characterized in that an average rate of change of the intermediate circuit voltage in a partial time period between two voltage steps is limited by a maximum average rate of change, the maximum average rate of change being defined according to the magnitude of the intermediate circuit voltage. The disclosure further relates to a tracking device designed to perform the tracking method and to an inverter equipped with the tracking device.

Growing community of inventors

Niestetal, Germany

Alexander Unru