Abstract: In a method for controlling an operation of an electric motor, electric voltages applied to electric phases of the electric motor are generated and output in a modulation in a controlled manner dependent on a rotor position of the electric motor and a target/actual comparison of at least one first variable which characterizes a load on the electric motor or an actual rotational speed of the electric motor. A rotor position angle, which characterizes the rotor position, is complemented with a specified preliminary control angle and another regulated preliminary control angle component upon reaching a field weakening range of the electric motor so as to form a sum angle. The sum angle is used to characterize the rotor position in the modulation upon reaching the field weakening range. The disclosure also relates to a device for controlling an operation of an electric motor.

Abstract: A method recognizes a wire-break fault during operation of a brushless DC motor. A switch-on delay duration of a transition of an electrical phase potential that rests on the stator winding phase from a switch-off potential to a switch-on potential and a switch-off delay duration of the transition of the phase potential from the switch-on potential to the switch-off potential are detected for a stator winding phase of the stator winding of the motor during each pulse width modulation cycle period. Moreover, a lower deviation limit is defined for a deviation of detected switch-off delay durations from detected switch-on delay durations. A wire-break fault is deduced if the deviations of the detected switch-off delay durations from the detected switch-on delay durations fall below the lower deviation limit.