Damping of resonant peaks in an electric motor, which is operated using a converter with a voltage intermediate circuit, by increasing the losses produced in the region of critical natural frequencies

摘要

In a converter system having a voltage intermediate circuit which operates with a mains system input inductor in the step-up controller mode or has other input-side inductances, there is a risk of natural system oscillations being formed via discharge capacitances in conjunction with motors. If the motor now has an amplitude/frequency response with a pronounced resonant frequency in the region of such natural system oscillations, then there is a risk of higher voltages occurring at the motor star point (S) than on the motor phases (U, V, W). This is prevented by the invention in that materials, particularly capacitive elements such as lossy dielectrics or inductive elements which produce eddy current losses are used for the stator in the motor, such that these materials result in increased losses being produced in the region of system oscillations (fsys), which are stimulated asymmetrically with respect to ground potential, in the converter system (Lk, UR, L, M).