Sma Solar Technology Ag

Florian Steiper

Christian Gehrke

Claus Allert

Tobias Mueller

Volker Wachenfeld

Pablo Ignacio Correa Vasquez

A method for discharging a capacitor of an input or output circuit arrangement of an inverter for supplying current to a power supply grid includes determining voltage readings at connections of the input or output circuit arrangement and a DC link capacitor of the inverter; and calculating an upper limit voltage value of the DC link capacitor based on the measured values. The method also includes operating a DC/DC converter or a bridge arrangement of the inverter such that energy from the capacitor of the input or output circuit arrangement is transferred to the DC link capacitor, ending the method if the voltage across the DC link capacitor exceeds the upper voltage limit. Otherwise the method continues to transfer energy from the capacitor of the input or output circuit arrangement to the DC link capacitor until the capacitor is discharged to or below a lower limit voltage value.

Method for capacitor discharging for an inverter assembly

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.

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Kassel, Germany

Florian Steiper