Woodward Kempen Gmbh

Kk Wind Solutions A/s

Convertertec Deutschland Gmbh

Jörg Kretschmann

Stephan Engelhardt

Dirk Volker Leiting

Jan Van Leyen

Disclosed is a method for operating a three-phase inverter on a three-phase load. The three-phase inverter has a direct voltage intermediate circuit, at least one three-phase bridge circuit, and at least one control unit for controlling the bridge circuit. In the at least one bridge circuit, at least two power switches per phase are provided, which are connected in series parallel to the direct voltage intermediate circuit. Depending on predefined target voltage values of the three phases of the inverter, the power switches of each individual phase are actuated via the control unit such that a three-phase alternating voltage is generated on the three-phase load via switching operations of the power switches. Very good dynamic control behaviour can be achieved despite cost-effective dimensioning of the IGBT power switches of the three-phase bridge circuit.

Method for phase-separated overcurrent protection of a three-phase bridge circuit

Provided is an apparatus for delivering electrical power, in particular for delivering regeneratively produced electrical power, which has at least one converter and at least one filter for matching the delivery of power by the converter to a load impedance. Also provided is a method for operating the apparatus for delivering electrical power which allows improved monitoring of the functioning of the filters or mains filters and which uses means for determining at least one filter current in at least one filter, which means are designed in such a manner that said means make it possible to determine the at least one filter current during operation of the apparatus. Comparison means are provided and generate an error information signal using the desired value and actual value of the filter current and a predefinable error criterion.

High accuracy mains filter monitoring for a multi-phase power system

The invention relates to a method and a device for operating an asynchronous motor () with double feeds, having a stator () connected to a grid and a rotor () connected to an inverter (), said inverter () being designed such that it impresses a target value for an electrical variable in the rotor (). In a method according to the invention, after detecting a transient grid voltage change, a target value for the electrical variable determined from at least the rotor flux and the stator flux is impressed in the rotor () such that an active reduction in the torque occurring during the transient grid voltage change is achieved. The target value of the electrical variable is preferably determined from a suitable weighting of the stator flux, rotor flux, stator voltage, stator current, rotor current, and, if available as a measured variable, stator voltage.; In this manner, torque peaks are similarly prevented for various types of grid faults, and the maximum time value of the rotor current is optimally reduced, and a rapid return to regular operation of the asynchronous motor is made possible.

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Kempen, Germany

Jörg Kretschmann