Sma Solar Technology Ag

Wolfgang Reichenbaecher

Andreas Falk

Frank Greizer

Joachim Ralf Laschinski

Wilfried Groote

Oliver Arend

Peter Simon

Alexander Ahlborn

A method of connecting a photovoltaic device to an AC power grid through an inverter includes monitoring a DC voltage at an input of an inverter, and activating the inverter when the monitored DC voltage exceeds a first predetermined threshold. The method further includes synchronizing an output voltage of the inverter with a grid voltage, connecting an output of the inverter to the AC power grid upon synchronization if the monitored DC voltage exceeds second predetermined threshold, and deactivating the inverter if a detected power being fed through the inverter falls below a predetermined power threshold while maintaining the connection between the output of the inverter and the AC power grid. Lastly, the method includes disconnecting the output of the deactivated inverter from the grid if the monitored DC voltage falls below a third predetermined threshold. Further, an apparatus that performs such functionality is also provided.

Method of and apparatus for connecting a photovoltaic device to an AC power grid

A method for determining a load capability of a direct current ('DC') voltage source connectable to an alternating current ('AC') power grid having a predetermined frequency via an inverter and a grid disconnect switch includes controlling, while the grid disconnect switch is in an open position, the inverter so as to convert a DC input voltage to a test frequency different than the predetermined frequency of the AC power grid so as to increase a test load acting on the DC voltage source above an internal consumption of the inverter at the predetermined frequency. The DC input voltage is measured while the grid disconnect switch is in the open position.

Determination of the load capability of a DC voltage source which is connectable to an electric power grid via an inverter and a grid disconnect switch

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Staufenberg, Germany

Wolfgang Reichenbaecher