Fronius International Gmbh

Gerhard Reiter

Friedrich Oberzaucher

Andreas Luger

Bernhard Doppelbauer

Bernhard Staudinger

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

Method and device for determining an insulation resistance Rof a photovoltaic system () with respect to earth potential (EP), comprising a DC-DC converter unit () which converts a first DC voltage generated by the photovoltaic generator () into a second DC voltage which is applied to an intermediate circuit () that temporarily stores the electrical energy, supplied by the photovoltaic generator (), for a DC-AC converter unit () connected thereto, wherein the intermediate circuit () contains a reference node (BK) having an adjustable reference potential (BP), and comprising a measuring unit () which picks up the measuring voltages between the reference potential (BP) and the earth potential (EP) at different reference potentials (BP), and an evaluation unit () which evaluates the measuring voltages that have been picked up in order to determine the insulation resistance of the photovoltaic generator () of the photovoltaic system ().

Growing community of inventors

Laakirchen, Austria

Gerhard Reiter