Abstract: The present invention relates to a three-phase inverter (1) with a circuit arrangement having a DC-voltage input (2) for at least one direct voltage source, and a three-phase alternating voltage output (15) for feeding into a three-phase alternating voltage mains (19), wherein said inverter comprises a three-phase bridge circuit (20) as well as at least one divided intermediate circuit, wherein said inverter (1) is configured to be transformerless, wherein said neutral conductor (N) of the mains (19) is separated from the central point (M) of the intermediate circuit and the inverter (1) is connected to the alternating voltage mains (19) via a three-conductor connection (15).

Abstract: A method of activating a Multi-String inverter for photovoltaic generators (1a, 1b) of a photovoltaic plant (6), the Multi-String inverter incorporating on the input side a separate DC-DC converter (2a, 2b) for each generator string (photovoltaic generator) (1a, 1b) and each output of the DC-DC converters (2a, 2b) being connected in parallel and to an input of a DC-AC converter (3) and the DC-AC converter (3) being connected with an alternating current mains (4) for feeding into the mains aims at improving efficiency. This is achieved in that one or several electrical variables, namely input current, input voltage and/or input power are measured at each DC-DC converter (2a, 2b) and at least one of the DC-DC converters (2a, 2b) changing its operating condition as a is function of this measurement when a limit value and/or a range is exceeded in such a manner that its power loss is reduced so that the energy yield of the photovoltaic plant (6) is increased.

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.

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: 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: 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: The subject matter of the present invention is a method for monitoring a photovoltaic generator (1) for generating current with a number of solar cells connected between two external connections by repeated feeding of a current with a frequency spectrum into the generator current circuit, detecting thereby a respective frequency response in the frequency spectrum with the supplied current as the input variable and an electric variable of the generator as the output variable, and detecting a change in the frequency response for monitoring the photovoltaic generator (1) in the event of a change during repeated feeding.

Abstract: An inverter (1) with galvanic separation including a resonant converter (2) and an upstream mounted boost chopper (3) is intended to provide galvanic separation in the context of a variable input and output voltage as it exists in photovoltaic systems, with the efficiency being intended to be optimized over the entire input voltage range. This is achieved in that a boost chopper (3) or a buck chopper (4) is mounted upstream of the resonant converter (2).

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: An inverter is devised to avoid high-frequency voltages at input terminals and to allow good efficiency thanks to its simple and cost-optimized circuit layout. This is achieved by a method of converting a direct current voltage, more specifically from a photovoltaic source of direct current voltage, into an alternating current voltage at a frequency through a bridge circuit comprising switching elements (V1-V4) and free-wheeling elements (D1-D4), said switching elements (V1-V4) being on the one side gated at the frequency and on the other side clocked at a high clock rate, a direct current voltage circuit, an alternating current voltage circuit and a plurality of free-wheeling phases being provided.