Abstract: The invention relates to the protection of an electric drive system. If a voltage spike occurs on the input of a current converter of the electric drive system via the intermediate circuit, then in order to dissipate said voltage spike in the electric drive system, a change is made to and fro between a motor operating mode and a generator operating mode in order to dissipate the electrical energy from the intermediate circuit capacitor. For the motor operating mode and the generator operating mode, in each case suitable space phasor vectors can be predefined. This permits particularly simple and rapid activation in order to dissipate the electrical energy in the electric drive system.

Abstract: The invention relates to the protection of an electric drive system. If a voltage spike occurs on the input of a current converter of the electric drive system via the intermediate circuit, then in order to dissipate said voltage spike in the electric drive system, a change is made to and fro between a motor operating mode and a generator operating mode in order to dissipate the electrical energy from the intermediate circuit capacitor. For the motor operating mode and the generator operating mode, in each case suitable space phasor vectors can be predefined. This permits particularly simple and rapid activation in order to dissipate the electrical energy in the electric drive system.

Abstract: The invention relates to a method for operating an asynchronous machine comprising the steps: determining an operating point trajectory for the asynchronous machine for a plurality of desired torques of the asynchronous machine by calculating 2-tuples from longitudinal current values and cross current values in a synchronously rotating coordinate system of the asynchronous machine; calculating a slip frequency of the asynchronous machine for each of the 2-tuples calculated from longitudinal current values and cross current values; determining a current rotor speed of the asynchronous machine; calculating an excitation frequency of the asynchronous machine by summation of the calculated slip frequency and the current rotor speed weighted with the number of pole pairs of the asynchronous machine; and comparing the calculated excitation frequency of the asynchronous machine with at least one predetermined resonance frequency value of the asynchronous machine.

Abstract: The invention relates to a method for operating an asynchronous machine comprising the steps: determining an operating point trajectory for the asynchronous machine for a plurality of desired torques of the asynchronous machine by calculating 2-tuples from longitudinal current values and cross current values in a synchronously rotating coordinate system of the asynchronous machine; calculating a slip frequency of the asynchronous machine for each of the 2-tuples calculated from longitudinal current values and cross current values; determining a current rotor speed of the asynchronous machine; calculating an excitation frequency of the asynchronous machine by summation of the calculated slip frequency and the current rotor speed weighted with the number of pole pairs of the asynchronous machine; and comparing the calculated excitation frequency of the asynchronous machine with at least one predetermined resonance frequency value of the asynchronous machine.