DAMPING OF RESONANT PEAKS IN AN ELECTRIC MOTOR WHICH IS OPERATED USING A CONVERTER WITH AN INTERMEDIATE VOLTAGE CIRCUIT, BY MEANS OF MATCHED IMPEDANCE TO GROUND AT THE MOTOR STAR POINT, AND A CORRESPONDING ELECTRIC MOTOR

摘要

A system and method for damping of resonant peaks in an electric motor which is operated using a converter with an intermediate voltage circuit, by means of a matched impedance to ground at the motor star point, and a corresponding electric motor is disclosed. In a converter system having an intermediate voltage circuit which operates with a mains system input inductor in the step-up converter 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 than in the motor phases. This is prevented by the present invention by a termination of the lattice network, which is formed by the winding sections, in the motor at the motor star point by means of a suitably selected impedance with respect to ground, which advantageously comprises a series circuit formed from a non-reactive resistance and a capacitance.