Proposed scheme for plugging three-phase induction motor

The paper presents a proposed scheme for fast braking of induction motor drive system. The proposed braking strategy is based on the injection of an AC voltage to the rotor winding from three-phase SVPWM inverter during braking. The injected voltage must have the same frequency, same phase shift and opposite in direction to the rotor induced voltage. The purpose of this method is to reduce the rotor and stator high currents during reverse current braking (plugging), to an acceptable value. A model of the proposed braking strategy is implemented using the well known Matlab/Simulink software package. The different characteristics of the drive system are investigated and the usefulness of the braking system is verified with a special consideration given to the currents in the machine during braking.