Sma Solar Technology Ag

Pablo Ignacio Correa Vasquez

Tobias Mueller

Claus Allert

Alexander Unru

Henrik Wolf

Andreas Knobloch

Volker Wachenfeld

Christian Gehrke

Harald Drangmeister

Florian Steiper

Tobias Müller

Tobias MÜLLER

A method and system for operating an inverter, which has a terminal with four conductor connectors for connection of the inverter to three outer conductors and to a neutral conductor of an AC voltage grid is disclosed. The method includes determining a connection configuration of the inverter to the AC voltage grid by actuating switching elements of a bridge circuit of the inverter to generate a zero-phase sequence system having a zero-phase sequence system current, and measuring and evaluating output currents of the inverter with respect to the zero-phase sequence system current. The method also includes identifying a presence of a connection of the neutral conductor to a conductor connector provided for connection to the neutral conductor when the zero-phase sequence system current exceeds a prescribed threshold value and identifying that the neutral conductor is not connected to the conductor connector provided for connection to the neutral conductor otherwise.

Inverter with identification of neutral connection

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

The disclosure relates to a method for operating an inverter that includes at least one bridge assembly that is actuated in a modulated manner for supplying electrical power to an energy supply network. Initially, the inverter is operated by the unipolar actuation of the at least one bridge assembly and the energy supply network is monitored for the presence of a network fault. If a network fault is detected, the inverter is operated at least at intervals by the bipolar actuation of the at least one bridge assembly. The disclosure further relates to a network fault-tolerant inverter which is equipped for carrying out the method.

Operating method for an inverter and grid fault tolerant inverter

A method for converting DC power from a source into AC power by means of an inverter which includes three bridge branches, each having a phase output, is described. During grid-connected operation, the bridge branches are actuated in such a way that the AC power is fed, as three-phase grid-compliant power, into a grid. During emergency operation of the inverter, the AC power is provided as single-phase island grid by two of the three bridge branches at the phase outputs thereof, wherein the inverter is disconnected from the grid.

Single-phase emergency operation of a three-phase inverter and corresponding inverter having a polyphase to single phase changeover operation

Growing community of inventors

Bad Neustadt an der Saale, Germany

Pablo Ignacio Correa Vasquez