Damping control of induction motor traction system in single-pulse mode of field weakening region

This paper proposes a procedure to apply a damping control to induction motor driven system in the single-pulse mode. In this mode, the amplitude of voltage vector is kept constant and it is determined by the filter capacitor voltage. Therefore, there is a possibility that the oscillation of the filter capacitor voltage deteriorates the torque control performance by fluctuation of the rotor flux. In this regard, this paper examines the oscillation of filter capacitor voltage and the dynamics of rotor magnetic flux by the frequency characteristics. This study reveals that the inversed value of the resonance frequency of LC input filter should be lower than the secondary time constant of the induction motor in order to avoid influence of the oscillation of the filter capacitor voltage to the rotor flux fluctuation. The proposed method is verified by the experimental tests with 0.75-kW-class miniature-model.