Sma Solar Technology Ag

Sma Technologie Ag

Gerd Bettenwort

Joachim Ralf Laschinski

Markus Hopf

Matthias Victor

Sebastian Bieniek

Oliver Arend

Wolfgang Kurt Reichenbächer

Gerald Leonhardt

Sven Bremicker

Marcel Kratochvil

Frank Greizer

Holger Behrends

Jens Klein

Christopher Merz

Thorsten Buelo

Christian Kühnel

Jens Friebe

Oliver Prior

Claus Allert

Bernd Engel

Daniel Premm

Stijn Stevens

Yehia Tarek Fawzy

Ralf Juchem

Adrian Haering

Christian Kuehnel

Olaf Proeve

Tobias Müller

Lutz Eidenmueller

Gerald Alexander Leonhardt

Thorsten BÜLO

Adrian Häring

Olaf Pröve

Lutz Eidenmüller

A method for detecting a potential-induced degradation (PID) of PV modules of a PV installation includes operating a PV generator at a maximum power point (MPP), at a first generator voltage (U) and first generator current (I), and at a second generator voltage (U) and second generator current (I), where a first power (P) at the first generator voltage (U) is in a predefined first ratio V=P/Pand V&#x2264;1, with the power (P) at the maximum power point (MPP) of the PV generator, and where a second power (P) at the second generator voltage (U) is in a predefined second ratio V=P/Pand V&#x3c;1, with the first power (P) of the PV generator, and where a quantity Y that characterizes a progress of the potential-induced degradation (PID) is determined from the values of the voltages (U, U) and/or the currents (I, I).

Method and device for recognising faults in a photovoltaic (PV) generator

A method for determining a currently maximum possible power of a photovoltaic (PV) installation operated in a curtailed manner and including a PV generator having at least one string, wherein the at least one string includes a series circuit of PV modules, in which at least one PV module is connected to adjacent PV modules in the string via a coupling circuit. The installation further includes an inverter which is connected, on the output side, to an energy supply grid and is connected, on the input side, to the PV generator. The installation also includes a controller for controlling the inverter and the coupling circuit, wherein the controller, in conjunction with the coupling circuit, is designed to vary a power drain of the PV module assigned to it relative to a power drain of the adjacent PV modules during operation of the PV installation.

Method for determining a maximum possible power of a PV installation, and PV installation

For determining the topology of a grid section of an AC power grid, the grid section comprising a grid connection point, at least one branch branching off from the grid connection point and including a plurality of energy consumption and/or energy generation units, and at least one measurement point in the at least one branch, dependencies of variations of a grid voltage measured at the at least one measurement point based on variations of connection power values of at least some individual ones of the energy consumption and/or energy generation units are determined.

Grid diagram creation and operation control

A protective device for a photovoltaic system includes at least one input for connection to a photovoltaic generator and at least one output for delivery of an electric power supplied from the photovoltaic generator. The protective device includes a detection device for a signal applied via the at least one output, and is configured to provide a low level-limited voltage at the at least one output if an applied signal does not meet a predetermined criteria, and is further configured to connect the at least one output with low resistance to the at least one input via a switching device if the applied signal meets the predetermined criteria.

Protective device for a photovoltaic system

A device and corresponding method for monitoring a photovoltaic system to detect an occurrence of events impairing normal operation of the photovoltaic system is provide. The photovoltaic system includes a photovoltaic generator including a first group of photovoltaic modules and a second group of photovoltaic modules being different from the first group. The device includes a first and a second pair of coupling means, both pairs including signal coupling-in means for coupling a test signal into the photovoltaic generator, and a signal coupling-out means for coupling out a response signal from the photovoltaic generator, the first pair of coupling means configured to selectively detect the occurrence of the events in the first group of photovoltaic modules, and the second pair of coupling means configured to selectively detect the occurrence of the events in the second group of photovoltaic modules.

Device and method for monitoring a photovoltaic system

An inverter for feeding a grid-compatible AC voltage into a grid is described, wherein the inverter includes an inverter bridge for converting a DC voltage to a first AC voltage and a grid interface between the inverter bridge and the grid for converting the first AC voltage to the grid-compatible AC voltage for feeding into the grid. An AC interface via which an AC module for feeding into the grid can be connected, is arranged between the inverter bridge and the grid interface.

Inverter with an AC interface for the connection of AC modules

For the purpose of determining a fault current component of a differential current which is measured as a current sum over a plurality of lines carrying a current of an AC current generator, an electric signal which depends on generator voltages present at the AC current generator with respect to earth potential and which is in phase with a leakage current component of the differential current is generated. The electric signal is scaled by multiplying it by a scaling factor; and the scaled electric signal is subtracted from the differential current to obtain a remainder. The scaling factor is repeatedly updated such that the effective value of the remainder reaches a minimum at the present value of the scaling factor.

Determination of the fault current component of a differential current

A method for determining a maximum power point (MPP) of a photovoltaic generator (PV) by variation of at least one parameter of search voltage and search current, within a maximally searchable search area on a power/voltage curve is disclosed. The method includes initializing by defining a start point with a start voltage and a start current, searching for the maximum power point (MPP) in at least one search direction by repeated variation of the search voltage or search current in the search area taking account of at least two limiting conditions for limiting the search area, wherein at least one of the limiting conditions for limiting the search area are is determined with evaluation of parameters provided in an operating state already attained during the search, and ending the search if one of the at least two limiting conditions for limiting the search area is met.

Method for determining a maximum power point of photovoltaic generators

A method for detecting an arc fault in a photovoltaic power circuit includes operating a photovoltaic generator at a first working point. A first signal related to a DC-current and/or a DC-voltage in the power circuit is determined. The first signal is analyzed and it is determined whether the signal indicates the presence of an electric arc in the power circuit. If so, the photovoltaic generator is operated at a second working point and a second signal related to the DC-current and/or the DC-voltage is determined. The first and second signals are then compared; and the occurrence of an arc fault in the power circuit is selectively signaled based on the comparison.

Method and system for detecting an arc fault in a photovoltaic power system

A method includes searching for a point of maximum power based on a systematic load variation, setting the point of maximum power as the operating point of the photovoltaic generator, and tracking the operating point based on a load variation with a narrow variation range. The method also includes analyzing operating variables of the photovoltaic generator to determine the level of probability that the operating point deviates from the point of maximum power, selectively interrupting the tracking and carrying out another search to determine the point of maximum power as a function of the analysis of the operating variables, and setting the point of maximum power as the operating point, and resuming the tracking. The method further takes into account previous searches carried out in the presence of comparable operating variables to determine the probability.

Method for operation of a photovoltaic generator at an operating point of maximum power

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 matching the power of a photovoltaic system producing electric energy by which a working point at which the system produces maximum power is set by changing the working point in an MPP matching process and by comparing the system power, which changes as a result thereof, is intended to be suited both for stationary characteristic curves and for non stationary generator characteristic curves and to be easy to carry out so that the best working point is always set, even when the system is subjected to external interfering factors. This is achieved in that one or several additional control steps or control cycles are performed in order to track during the matching process a power point changing under external impact for a working point of even higher power to be set.

Maximum power point matching method

A method of activating a Multi-String inverter for photovoltaic generators () of a photovoltaic plant (), the Multi-String inverter incorporating on the input side a separate DC-DC converter () for each generator string (photovoltaic generator) () and each output of the DC-DC converters () being connected in parallel and to an input of a DC-AC converter () and the DC-AC converter () being connected with an alternating current mains () for feeding into the mains aims at improving efficiency. This is achieved in that one or several electrical variables, namely input current, input voltage and/or input power are measured at each DC-DC converter () and at least one of the DC-DC converters () changing its operating condition as a function of this measurement when a limit value and/or a range is exceeded in such a manner that its power loss is reduced so that the energy yield of the photovoltaic plant () is increased.

Method for activating a multi-string inverter for photovoltaic plants

Method for matching the power of a photovoltaic system to a working point at which the system produces maximum power

A method of finding a power maximum of a photovoltaic generator using an MPP regulator of a photovoltaic current converter by means of which a maximum generator power is set at an operating point of the generator's characteristic curve is intended to supply improved efficiency when the generator is partially shadowed. This is achieved by switching the MPP regulator off in order to next load and/or unload the generator to allow a new operating point of the generator's characteristic curve to set and by next switching the MPP regulator on again.

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Kassel, Germany

Gerd Bettenwort