Abstract: A method for determining a currently maximum possible power of a photovoltaic (PV) installation operated in a curtailed manner and including a PV generator having at least one string, wherein the at least one string includes a series circuit of PV modules, in which at least one PV module is connected to adjacent PV modules in the string via a coupling circuit. The installation further includes an inverter which is connected, on the output side, to an energy supply grid and is connected, on the input side, to the PV generator. The installation also includes a controller for controlling the inverter and the coupling circuit, wherein the controller, in conjunction with the coupling circuit, is designed to vary a power drain of the PV module assigned to it relative to a power drain of the adjacent PV modules during operation of the PV installation.

Abstract: A method for determining a currently maximum possible power of a photovoltaic (PV) installation operated in a curtailed manner and including a PV generator having at least one string, wherein the at least one string comprises a series circuit of PV modules, in which at least one PV module is connected to adjacent PV modules in the string via a coupling circuit. The installation further includes an inverter which is connected, on the output side, to an energy supply grid and is connected, on the input side, to the PV generator. The installation also includes a controller for controlling the inverter and the coupling circuit, wherein the controller, in conjunction with the coupling circuit, is designed to vary a power drain of the PV module assigned to it relative to a power drain of the adjacent PV modules during operation of the PV installation.

Abstract: In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

Abstract: An inverter for feeding a grid-compatible AC voltage into a grid is described, wherein the inverter includes an inverter bridge for converting a DC voltage to a first AC voltage and a grid interface between the inverter bridge and the grid for converting the first AC voltage to the grid-compatible AC voltage for feeding into the grid. An AC interface via which an AC module for feeding into the grid can be connected, is arranged between the inverter bridge and the grid interface.

Abstract: In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

Abstract: The method of detecting an arc fault in a power circuit includes determining a first signal related to current flowing in the power circuit is determined and analyzing the first signal to determine whether the signal indicates the presence of an electric arc in the power circuit. In case the first signal indicates the presence of an electric arc in the power circuit, means for suppressing an electric arc are activated. A second signal related to current flowing in the power circuit is then determined and analyzed. An occurrence of an arc fault in the power circuit is signaled if the second signal does not indicate the presence of an electric arc. The system for detecting an arc fault is designed to perform a corresponding method.

Abstract: The invention relates to a photovoltaic system for feeding three-phase current to a power grid that includes several monophase or three-phase photovoltaic inverters that can be connected to the power grid at the output end and are each fitted with a disconnecting device at the output end. The system includes several photovoltaic generators that are connected to the input end of the photovoltaic inverters. A central control and monitoring unit is connected between the photovoltaic inverters and the power grid. The control and monitoring unit has a grid monitoring device at the feeding point to the grid to measure one or more grid parameters. At least one communication link is provided between the individual photovoltaic inverters or the individual disconnecting devices and the connected central control and monitoring unit such that the connecting devices can disconnect the individual photovoltaic inverters from the power grid by means of a control instruction signal of the communication link.

Abstract: A protection system configured to couple between a generator that has a number of partial strings and an inverter includes a control device, and a series-connection switching device configured to selectively connect the partial strings together in series. The system also includes a parallel-connection switching device configured to selectively connect the partial strings together in parallel, wherein the series-connection switching device is actuated by the control device such that it interrupts the series connection of the partial strings in case of a hazard, and the parallel-connection switching device is actuated by the control device such that it connects the partial strings together in parallel in case of a hazard.

Abstract: The method of detecting an arc fault in a power circuit includes determining a first signal related to current flowing in the power circuit is determined and analyzing the first signal to determine whether the signal indicates the presence of an electric arc in the power circuit. In case the first signal indicates the presence of an electric arc in the power circuit, means for suppressing an electric arc are activated. A second signal related to current flowing in the power circuit is then determined and analyzed. An occurrence of an arc fault in the power circuit is signaled if the second signal does not indicate the presence of an electric arc. The system for detecting an arc fault is designed to perform a corresponding method.

Abstract: A method of connecting a photovoltaic device to an AC power grid through an inverter includes monitoring a DC voltage at an input of an inverter, and activating the inverter when the monitored DC voltage exceeds a first predetermined threshold. The method further includes synchronizing an output voltage of the inverter with a grid voltage, connecting an output of the inverter to the AC power grid upon synchronization if the monitored DC voltage exceeds second predetermined threshold, and deactivating the inverter if a detected power being fed through the inverter falls below a predetermined power threshold while maintaining the connection between the output of the inverter and the AC power grid. Lastly, the method includes disconnecting the output of the deactivated inverter from the grid if the monitored DC voltage falls below a third predetermined threshold. Further, an apparatus that performs such functionality is also provided.

Abstract: A method of connecting a photovoltaic device to an AC power grid through an inverter includes monitoring a DC voltage at an input of an inverter, and activating the inverter when the monitored DC voltage exceeds a first predetermined threshold. The method further includes synchronizing an output voltage of the inverter with a grid voltage, connecting an output of the inverter to the AC power grid upon synchronization if the monitored DC voltage exceeds a second predetermined threshold, and deactivating the inverter if a detected power being fed through the inverter falls below a predetermined power threshold while maintaining the connection between the output of the inverter and the AC power grid. Lastly, the method includes disconnecting the output of the deactivated inverter from the grid if the monitored DC voltage falls below a third predetermined threshold. Further, an apparatus that performs such functionality is also provided.

Abstract: A solar power plant includes at least one photovoltaic module for generating power to be fed in a multi-phase grid. At least one inverter is provided for converting a direct voltage generated by the at least one photovoltaic module into an alternating mains voltage. A mains transformer is coupled to receive the alternating mains voltage from the inverter. The inverter is coupled to a primary side of the mains transformer. A direct voltage source coupled between an output of the at least one inverter and an input of the mains transformer such that a potential of the at least one photovoltaic module is displaced and that a bias voltage is set which is different from zero volts.

Abstract: The invention relates to a photovoltaic system for feeding three-phase current to a power grid that includes several monophase or three-phase photovoltaic inverters that can be connected to the power grid at the output end and are each fitted with a disconnecting device at the output end. The system includes several photovoltaic generators that are connected to the input end of the photovoltaic inverters. A central control and monitoring unit is connected between the photovoltaic inverters and the power grid. The control and monitoring unit has a grid monitoring device at the feeding point to the grid to measure one or more grid parameters. At least one communication link is provided between the individual photovoltaic inverters or the individual disconnecting devices and the connected central control and monitoring unit such that the connecting devices can disconnect the individual photovoltaic inverters from the power grid by means of a control instruction signal of the communication link.

Abstract: A solar power plant with a plurality of photovoltaic modules for generating a power to be fed in a multi-phase grid, several photovoltaic strings, which are allocated to different phases, being connected to a primary side of a mains transformer and at least one inverter for converting the direct voltage generated by the photovoltaic modules into an alternating mains voltage conforming to the grid being provided and said mains transformer being provided with a neutral conductor and with a grounded terminal, is intended to be improved in such a manner that the life of the photovoltaic modules, in particular in case of thin-film modules, is increased, allowing for high conversion efficiency of the inverters at low wiring costs. This is achieved in that an additional direct voltage source is inserted between the neutral conductor and ground in such a manner that the potential of the photovoltaic strings is displaced and that a bias voltage is set, which is different from zero volt.

Abstract: The subject matter of the invention is an inverter including a casing (1), said casing (1) including at least two casing chambers (2, 3) that are each closable through a separate cover (2a, 3a).

Abstract: A solar power plant with a plurality of photovoltaic modules for generating a power to be fed in a multi-phase grid, several photovoltaic strings, which are allocated to different phases, being connected to a primary side of a mains transformer and at least one inverter for converting the direct voltage generated by the photovoltaic modules into an alternating mains voltage conforming to the grid being provided and said mains transformer being provided with a neutral conductor and with a grounded terminal, is intended to be improved in such a manner that the life of the photovoltaic modules, in particular in case of thin-film modules, is increased, allowing for high conversion efficiency of the inverters at low wiring costs. This is achieved in that an additional direct voltage source is inserted between the neutral conductor and ground in such a manner that the potential of the photovoltaic strings is displaced and that a bias voltage is set, which is different from zero volt.

Abstract: A method of converting a direct voltage generated by a decentralized power supply system into three-phase alternating voltage by means of a plurality of single-phase inverters (WR1-WR3), said alternating voltage being provided for supplying an electric mains, is intended to avoid inadmissible load unbalances using single-phase inverters. This is achieved in that, upon failure of one inverter (WR1-WR3), an asymmetrical power supply distribution is reduced by limiting the output of the other inverters. The method makes it possible to simplify three-phase voltage monitoring.

Abstract: A method of matching the power of a photovoltaic system producing electric energy by which a working point at which the system produces maximum power is set by changing the working point in an MPP matching process and by comparing the system power, which changes as a result thereof, is intended to be suited both for stationary characteristic curves and for non stationary generator characteristic curves and to be easy to carry out so that the best working point is always set, even when the system is subjected to external interfering factors. This is achieved in that one or several additional control steps or control cycles are performed in order to track during the matching process a power point changing under external impact for a working point of even higher power to be set.

Abstract: The subject matter of the invention is an inverter including a casing (1), said casing (1) including at least two casing chambers (2, 3) that are each closable through a separate cover (2a, 3a).

Abstract: A method of converting a direct voltage generated by a decentralized power supply system into three-phase alternating voltage by means of a plurality of single-phase inverters (WR1-WR3), said alternating voltage being provided for supplying an electric mains, is intended to avoid inadmissible load unbalances using single-phase inverters. This is achieved in that, upon failure of one inverter (WR1-WR3), an asymmetrical power supply distribution is reduced by limiting the output of the other inverters. The method makes it possible to simplify three-phase voltage monitoring.