Method of and apparatus for operating a double-fed asynchronous machine in the event of transient mains voltage changes

Abstract

The invention relates to a method and a device for operating an asynchronous motor (1) with double feeds, having a stator (1a) connected to a grid and a rotor (1b) connected to an inverter (6), said inverter (6) being designed such that it impresses a target value for an electrical variable in the rotor (1b). 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 (1b) 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.

Dependencies are inferred from the claim text.