Fronius International Gmbh

Gerhard Wallisch

Joachim Danmayr

Friedrich Oberzaucher

Andreas Luger

Bernhard Staudinger

Ruben Overbeck

Florian Durst

Daniel Chalupar

In order to protect an inverter from prohibited switching states, a monitor including monitoring inputs and monitoring outputs is provided. The monitoring inputs are connected to the control outputs in order to receive the switching patterns, and the monitoring outputs are connected to the power switches. The monitor is designed to compare a transition from a first switching pattern to a second switching pattern with a number of prohibited transitions and/or with a number of permitted transitions and block the second switching pattern in the event of a match with one of the prohibited transitions and/or in the event of a deviation from the number of permitted transitions and to output the second switching pattern to the power switches via the monitoring outputs in the event of a deviation from the number of prohibited transitions and/or in the event of a match with one of the permitted transitions.

Monitoring unit for an inverter

An inverter includes a DC/DC converter which converts a direct current received from a DC voltage source into an intermediate circuit voltage of an intermediate circuit, a DC/AC converter which converts the intermediate circuit voltage into an AC voltage, and a monitoring unit which monitors capacitors of the intermediate circuit for protection against overvoltages. If an overvoltage occurs at one of the capacitors of the intermediate circuit the overvoltage unit decouples the DC voltage source from the intermediate circuit by actuating the DC/DC converter.

Inverter with monitoring unit for intermediate circuit protection

A photovoltaic inverter has a DC input for connection to a DC source, a DC-DC converter, an intermediate circuit, a DC-AC converter, an AC disconnector, a control device, an AC connection for connection to a supply network and, if present, a consumer, a battery stage, and a battery connection for connection to a buffer battery, and a method operates a photovoltaic inverter of this kind. A switched-mode power supply is connected on the input side to the AC connection and on the output side to the battery stage so that, if the DC source is deactivated, the intermediate circuit can be charged up to a threshold value via the switched-mode power supply and the battery stage, whereupon the AC disconnector can be actuated and the photovoltaic inverter can be connected to the supply network.

Photovoltaic inverter and method for operating a photovoltaic inverter

The invention relates to a method for testing a disconnection point () of a photovoltaic inverter () and to a photovoltaic inverter () of this type. According to the invention, in a testing mode, an auxiliary voltage (U_Lx) is applied between the input (E_Lx) of each line (Lx) of the disconnection point () and an intermediate circuit potential (M), in each case, the first switching contacts (SW_Lx,1) are closed and the second switching contacts (SW_Lx,2) are opened alternately and vice versa, according to a switching pattern, and, for each switching pattern, the voltages (U_Lx,GD; U_MN) between the output (A_Lx) of each line (Lx) of the disconnection point () and the intermediate circuit potential (M) are measured, and the functionality of each switching contact (SW_Lx,j) is derived from the measured voltages (U_Lx,GD; U_MN).

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Pettenbach, Austria

Gerhard Wallisch