Sma Solar Technology Ag

Bernhard Schropp

Markus Hopf

Michael Viotto

Matthias Groene

Mathias Buenemann

The disclosure relates to a method for determining a characteristic curve for a photovoltaic (PV) string of a photovoltaic system having an inverter which is connected to the photovoltaic string and to a power supply network. The photovoltaic string includes a series connection of a plurality of photovoltaic modules, in which series connection at least one of the photovoltaic modules is integrated into the series connection of the photovoltaic modules via a DC/DC converter. The at least one DC/DC converter operates the photovoltaic module assigned thereto in a first operating mode M1 at a maximum power point by varying, over time, a conversion ratio of output voltage (U) to input voltage (U), and operates the photovoltaic module in a second operating mode M2 with a conversion ratio of output voltage (U) to input voltage (U) that is constant over time. The method includes operating the at least one DC/DC converter in the second operating mode M2 in response to a current signature for the current (I) through the photovoltaic string, determining the characteristic curve by varying the current Ior the voltage Uof the photovoltaic string by the inverter, and detecting values assigned to one another for current Iand voltage Uof the photovoltaic string in the second operating mode M2 of the DC/DC converter.

Method for determining a characteristic curve of a photovoltaic (PV) string, DC/DC converter, and photovoltaic system suitable for carrying out the method

A method for controlling a load by providing a total energy consumption and a time window for the total energy consumption of the load from one or more energy sources is described. The method includes determining of energy blocks, wherein the energy blocks are based on a power interval during a time interval, the time intervals are within the time window and the energy blocks are allocated energy-source-dependent costs, sorting of the energy blocks in ascending order according to the level of the costs per energy block and subsequent summation of quantities of energy that the energy blocks contain in ascending order of sorting until the total energy consumption of the load is reached. From this, on and off times of the load are determined by means of the time intervals that belong to the summed energy blocks, wherein the power intervals belonging to the respective energy blocks determine a power consumption of the load at the respective instant, and the load is actuated in accordance with the on and off times. An apparatus for carrying out the method is likewise disclosed.

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Kassel, Germany

Bernhard Schropp