Sma Solar Technology Ag

Denis Mende

Daniel Premm

Thorsten Buelo

Christian Schuetz

Stephan Sander

A method and associated system for minimizing grid feedback of a PV park to an energy supply grid connected to a point of common coupling is disclosed, wherein the PV park has a plurality of inverters divided into groups. The method includes, for at least a first inverter of each group, determining a first parameter representative of a first coupling impedance between the first inverter and the point of common coupling and determining a second parameter representative of a second coupling impedance between the group containing the first inverter and the point of common coupling. The method further includes storing the first parameter and the second parameter in an operating control unit of the first inverter, and, in daytime operation of the PV park, feeding in reactive power by the first inverter depending on the first parameter, said reactive power corresponding to the magnitude of a reactive power drawn by the respective underlying first coupling impedance. The method also includes, in night-time operation, deactivating all the inverters of a group with the exception of the first inverter and feeding in reactive power by the first inverter depending on the second parameter, wherein the reactive power fed in corresponds to a magnitude of a reactive power drawn by the respective underlying second coupling impedance.

Method for minimizing a network feedback of a PV park, inverter, and PV park

An inverter for converting DC power of a generator into grid-conforming AC power includes an inverter bridge circuit and a scanning circuit configured to trace at least one part of a characteristic curve of the generator to determine an MPP power value (P). The scanning circuit is configured, in the case of a derating to a derated power (P), to trigger a tracing of the characteristic curve with provision of a first power profile deviating from the derated power (P) if an enable signal is present at the inverter, and to indicate a start and an end of the tracing by outputting a start signal and an end signal, respectively. The scanning circuit is further configured to provide a second power profile as AC power upon receiving a start signal, wherein the first power profile has a deviation from the derated power (P) with a sign that is opposite to a sign of a deviation of the second power profile from the derated power (P).

Inverter, in particular as part of a power generation network, and method

A method and associated apparatus for operating a power station of fluctuating electrical capacity that, besides a voltage-setting system former outputting active power and reactive power and at least one load, is connected to a limited AC grid. The method and associated apparatus includes defining a desired self-contained operating range of the system former on the PQ level, in which operating range the system former is able to efficiently correct fluctuations arising in a mains voltage of the AC grid, ascertaining a present operating point of the system former on the PQ level, and controlling an output of active power and reactive power by the power station such that the operating point of the system former is kept in the desired operating range.

Method and apparatus for the operation of a power station of fluctuating performance connected, besides a system former and at least one load, to a limited AC system

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Grossalmerode, Germany

Denis Mende