Abstract: The disclosure relates to a housing of an electrical device for converting electrical power, including a main body and a cover. The cover closes the main body to define a self-contained interior space, wherein electrical and electronic components of the electrical device are arranged in the interior space of the housing. The cover is connected to the main body via a detchable securing structure, which may be arranged in the geometrical center of the cover. An electrical device has a housing of this type.

Abstract: A method of operating a transformerless inverter connected on the input side to a generator and on the output side to a multiphase AC grid and comprising a multi-phase inverter bridge with a switch between a midpoint of a DC intermediate circuit on the input side and a terminal for a neutral conductor of the multiphase AC grid, includes feeding electric power from the DC intermediate circuit into the AC grid by the inverter bridge with the switch closed when first operating conditions are present, and opening the switch when there is a transition from the first operating conditions to second operating conditions different from the first operating conditions. The method further includes feeding electric power from the DC intermediate circuit into the AC grid by the inverter bridge with the switch open when the second operating conditions are present, and closing the switch when there is a transition from the second operating conditions to the first operating conditions.

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: A method for the operational control of an inverter designed for DC/AC voltage conversion that has at least one direct-voltage input and that can be connected to a power supply grid via at least one alternating-voltage output, the inverter being involved in a power flow interaction with the grid in such a manner that, during operation of the inverter, a leakage current IA can occur, wherein the leakage current IA is controlled in the operational control.

Abstract: A method of operating a transformerless inverter connected on the input side to a generator and on the output side to a multiphase AC grid and comprising a multi-phase inverter bridge with a switch between a midpoint of a DC intermediate circuit on the input side and a terminal for a neutral conductor of the multiphase AC grid, includes feeding electric power from the DC intermediate circuit into the AC grid by the inverter bridge with the switch closed when first operating conditions are present, and opening the switch when there is a transition from the first operating conditions to second operating conditions different from the first operating conditions. The method further includes feeding electric power from the DC intermediate circuit into the AC grid by the inverter bridge with the switch open when the second operating conditions are present, and closing the switch when there is a transition from the second operating conditions to the first operating conditions.

Abstract: A method and device to discharge a filter capacitance at the output of an inverter for feeding electrical power from a generation unit into a grid via a grid connect switch is disclosed. The grid connect switch has a generation unit side and a grid side, and via AC grid terminals on the grid side of the grid connect switch, the filter capacitance is connected to at least one of the AC grid terminals. A voltage applied across the filter capacitance is rectified independent of a polarity thereof, and a rectified voltage of a fixed polarity is provided, and a DC voltage link of a power supply unit for supplying power to circuitry of the inverter is charged with this rectified voltage.

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 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: In an overvoltage protection apparatus before an inverter configured to feed electric energy from a DC voltage source into an AC power grid, the overvoltage protection apparatus includes a DC voltage input stage. The DC voltage input stage includes at least two current-carrying lines and an EMC filter including interference suppressing capacitors and interference suppressing inductors, and surge arrestors configured to divert overvoltages with respect to ground are connected to the current-carrying lines after the EMC filter, from a point of view of the DC voltage source.

Abstract: A load breaker arrangement includes first and second input terminals, respectively, and first and second output terminals. The arrangement also includes two relays connected in series with one another, wherein the two relays are coupled between the second input terminal and the second output terminal, a semiconductor switch connected in parallel with one of the two relays, and a third relay coupled between the first input terminal and the first output terminal. A control circuit, in a load breaker mode, turns on the semiconductor switch while the two relays and the third relay are closed, then opens the one of the two relays in parallel with the semiconductor switch, then opens the semiconductor switch to break a current between the second input and second output terminals, and then opens the other of the two relays not in parallel with the semiconductor switch and opens the third relay.

Abstract: In an overvoltage protection apparatus before an inverter configured to feed electric energy from a DC voltage source into an AC power grid, the overvoltage protection apparatus includes a DC voltage input stage. The DC voltage input stage includes, at least two current-carrying lines and an EMC filter including interference suppressing capacitors and interference suppressing inductors, and surge arrestors configured to divert overvoltages with respect to ground are connected to the current-carrying lines after the EMC filter, from a point of view of the DC voltage source.

Abstract: An inverter has two input lines; an inverter bridge connected between the input lines and including at least one half-bridge having two normally conductive gate-controlled semiconductor switches; a controller which supplies control voltages to the gates of the semiconductor switches in an operative state of the inverter; and a DC voltage source for supplying an auxiliary control voltage to the gates of the semiconductor switches in an inoperative state of the inverter so as to hold the inverter bridge in a non-conductive state between the input lines. The DC voltage source has a charging unit connected between the input lines in series with a further normally conductive gate-controlled semiconductor switch, and charging a storage unit for electric charge, which is connected to the gate of the further semiconductor switch such that this switch becomes non-conductive, when the storage unit has been sufficiently charged for providing the auxiliary control voltage.

Abstract: A method and device to discharge a filter capacitance at the output of an inverter for feeding electrical power from a generation unit into a grid via a grid connect switch is disclosed. The grid connect switch has a generation unit side and a grid side, and via AC grid terminals on the grid side of the grid connect switch, the filter capacitance is connected to at least one of the AC grid terminals. A voltage applied across the filter capacitance is rectified independent of a polarity thereof, and a rectified voltage of a fixed polarity is provided, and a DC voltage link of a power supply unit for supplying power to circuitry of the inverter is charged with this rectified voltage.

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: The subject matter of the invention is an inverter (1), comprising a casing (8) as well as at least one casing cover (2), said casing cover (2) being mechanically engaged with a safety plug (10), said safety plug (10) being in electrical connection with at least the one load-current circuit located on the DC side, the inverter being switched off or disconnected at least from the DC-side load-current circuit after removal of the safety plug from the casing (8).

Abstract: On an inverter (1) for converting an electric direct voltage, in particular of a photovoltaic direct voltage source into an alternating voltage with a direct voltage input with two terminals (DC+, DC?) and one alternating voltage output with two terminals (AC1, AC2) and with one bridge circuit including semiconductor switching elements (S1-S6), said bridge circuit comprising one first bridge branch (Z1) including four switching elements (S1-S4) and one second bridge branch (Z2) including two additional switching elements (S5, S6) as well as a freewheeling circuit provided with additional diodes (D7, D8), the efficiency is further increased without high frequency interferences and capacitive leakage currents having the possibility to occur on the generator side.

Abstract: The invention is directed to an inverter including a casing (1) with at least two chambers (2, 3), the one chamber (3) comprising the display (11) of a communication unit, said display (11) being pivotally disposed in the chamber (3).

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: 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: On an inverter (1) for converting an electric direct voltage, in particular of a photovoltaic direct voltage source into an alternating voltage with a direct voltage input with two terminals (DC+, DC?) and one alternating voltage output with two terminals (AC1, AC2) and with one bridge circuit including semiconductor switching elements (S1-S6), said bridge circuit comprising one first bridge branch (Z1) including four switching elements (S1-S4) and one second bridge branch (Z2) including two additional switching elements (S5, S6) as well as a freewheeling circuit provided with additional diodes (D7, D8), the efficiency is further increased without high frequency interferences and capacitive leakage currents having the possibility to occur on the generator side.