Fronius International Gmbh

Andreas Luger

Joachim Danmayr

Franz Fischereder

Juergen Pirchenfellner

Friedrich Oberzaucher

Gerhard Wallisch

Bernhard Doppelbauer

Stefan Bloechl

Gerhard Reiter

Dietmar Striegl

Bernhard Staudinger

Christoph Pernegger

Clemens Bittmann

Martin Moertenhuber

Andreas Muehlberger

Andreas MÜHLBERGER

Stefan BLÖCHL

Martin MÖRTENHUBER

Jürgen Pirchenfellner

A method and a photovoltaic inverter determines the system capacitance of a photovoltaic system relative to ground. The voltage required for the measurement can be provided by the intermediate circuit in the form of the intermediate circuit voltage, and the measuring device is designed to actuate an input short-circuit switch for short-circuiting the DC input with the AC disconnector open, as a result of which the intermediate circuit voltage can be applied to the DC input in the reverse direction, and the measuring device is configured to determine the system capacitance from the temporal waveform of the measured voltage after the switch of the voltage divider is closed.

Method and photovoltaic inverter for determining the system capacity of a photovoltaic system to ground

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 method and a photovoltaic inverter for determining the insulation resistance of a photovoltaic system relative to ground are provided. The voltage required for the measurement can be provided by an intermediate circuit in the form of an intermediate circuit voltage and a measuring device is designed to actuate an input short-circuit switch for short-circuiting a DC input with an AC disconnector open, as a result of which the intermediate circuit voltage can be applied to the DC input in the reverse direction. The measuring device is configured to record measured voltages with a switch of a voltage divider open and closed, and to determine the insulation resistance from the measured values of the two measured voltages recorded with the switch of the voltage divider open and closed.

Method and photovoltaic inverter for determining the insulation resistance of a photovoltaic system to ground

The invention relates to an inverter () for converting a direct voltage (U) into an alternating voltage (U) for feeding into a single-phase three-conductor network () and for supplying loads (), comprising a DC input (), an intermediate circuit () having an intermediate circuit center point (), a DC/AC converter () having at least two half bridges (), a control device (), and an AC output () for connecting to the single-phase three-conductor network () and the loads ('). The invention further relates to a method for operating such an inverter (). According to the invention, the control device () is designed to connect, in an emergency power operation (BOM), one half bridge () of the DC/AC converter () to a phase conductor (L) of the AC output (), to connect the other half bridge () of the DC/AC converter () to another phase conductor (L) of the AC output (), and to connect the intermediate circuit center point () to the neutral conductor (N) of the AC output () and to halve the amplitude of the output signal (U, U) of the half bridges (), and to perform a phase shift of the output signal (Uor U) of one half bridge (or) by 180&#xb0; such that at least some loads () can also be supplied in emergency power operation (BOM).

Inverter and method for operating an inverter

Power supply for an inverter and method for operating power supply. Power supply includes a throttle arranged to connect an output end of the inverter to an electric power supply network; a secondary-side auxiliary winding that is arranged on the throttle to transmit an output voltage (UA) of the inverter to a secondary side of the throttle; and a comparator unit. The comparator unit compares a voltage (U) of the electric supply network with the voltage (U) of the secondary side of the throttle, to supply, depending upon a result of the comparison of the electric supply network voltage (U) to the secondary side voltage (U) of the throttle, electric power to the power supply either from the electric supply network or via the secondary-side auxiliary winding.

Power supply for an inverter and method for operating power supply for an inverter

A method for an inverter, for inputting power output by a direct current voltage source in an alternating current voltage network chops the direct current voltage source by a bridge inverter by alternate switching of parallel-mounted and series-mounted circuit elements, in the form of a pulse width modulation, and the chopped power is transmitted via a transformer which is connected between the series-mounted elements. The transmitted power is then rectified and input in the alternating current voltage network via a down-converter transformer. In order to adapt the inverter to the power supplied, the switching times of the circuit elements of the bridge inverter are controlled or regulated. In order to provide a simple way of enhancing performance, the power output by the direct current voltage source is detected in particular on a cyclic or permanent basis and the switching times of the circuit elements of the bridge inverter, in particular the idle times and/or the interval duration and or the frequency for pulse width modulation, for switching the circuit elements are adjusted based on the detected power of the direct current voltage source.

Method for setting switching times, in particular idle times, of an inverter based on detected power, and inverter

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Pettenbach, Austria

Andreas Luger