Sma Solar Technology Ag

Bernd Engel

Frank Greizer

Matthias Victor

Peter Zacharias

Joachim Ralf Laschinski

Regine Mallwitz

Peter Drews

Guenther Cramer

Sven Bremicker

Wilfried Groote

Torben Westphal

Holger Becker

Thorsten Dingel

Ralf Joachim Laschinski

Gerd Bettenwort

Klaus Rigbers

Günther Cramer

Adrian Haering

A transformerless inverter that serves to feed electricity from a DC current source into an AC power grid, has an inverter bridge and a DC/DC converter connected upstream of the inverter bridge. The DC/DC converter converts an input DC voltage that is present between two input lines of the inverter into a DC link voltage present between two input lines of the inverter bridge. The inverter bridge converts the DC link voltage present at the input lines thereof into an output AC voltage. The DC/DC converter includes at least one resonant circuit that has a resonance inductance and a resonance capacitance and is connected on its input side via at least two clocked switches to one of the two input lines of the inverter or an intermediate potential line carrying a potential in between. The input lines of the inverter and the input lines of the inverter bridge are galvanically isolated from one another by a capacitive method. The resonant circuit may be undivided and is connected alternately to the two input lines of the inverter bridge.

Transformerless inverter comprising a DC/DC converter

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.

Method for limiting the generator voltage of a photovoltaic installation in case of danger and photovoltaic installation

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 (WR-WR), 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 (WR-WR), 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.

Method for converting direct voltage into three phase alternating voltage

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.

Device and method for generating alternating current

The object of the invention is a high-efficiency DC/DC converter, in particular for photovoltaic plants, incorporating a transformerless DC/DC converter operated in the resonant mode of operation for converting a unipolar direct input voltage with an associated positive pole (+) and with a negative pole (&#x2212;). There is imposed a resonance circuit incorporating at least one resonance inductance and at least one resonance capacitance, each resonance capacitance being connected to a respective one of the rectifier circuit arrangements in such a manner that the bipolar direct output voltage is provided, a voltage boosting circuit arrangement being connected to each resonance capacitance and to the rectifier circuit arrangement.

DC/DC converter

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.

Solar power plant

An inverter () for a grounded direct voltage source, in particular for a photovoltaic generator (), a battery or a fuel cell, for converting the direct voltage into an alternative voltage with a DC-DC converter () and a pulse inverter that is supplied by said DC-DC converter (), said DC-DC converter () being configured to be an oscillating circuit inverter and comprising a series resonant oscillating circuit, said DC-DC converter (), which is configured to be an oscillating circuit inverter, being configured to be a series-compensated oscillating circuit inverter with a choke (L) and a series-mounted capacitor array consisting of two or several oscillating circuit capacitors, a rectifier bridge branch including 2 diodes (D, D; D, D, . . . ), being connected to each of the partial oscillating circuit capacitors, said rectifier bridge branch being connected with its positive or its negative pole to output side intermediate circuit capacitors which are preferably connected in series so that said DC-DC converter () delivers at least two bipolar output voltages and is combined with the pulse inverter () with a divided voltage intermediate circuit that is supplied from the oscillating circuit inverter.

Inverter for grounded direct current source, more specifically for a photovoltaic generator

The invention is directed to an apparatus () for accommodating a plurality of individual inverters (), comprising a rack, the individual inverters () being removably mountable to the side elements of said rack, said rack having at least one terminal block () for receiving cables for current supply and evacuation.

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Wolfenbuettel, Germany

Bernd Engel