PROJECT TITLE :

Torsional vibration control of large induction motors using constant air gap flux scheme

ABSTRACT :

Comprehensive analysis of the starting period of inverter-fed massive induction motors reveals that these motors are subjected to additional elements of pulsating torsional torque. These torque pulsations might coincide with the natural torsional frequency of the big motor system and produce hazardous shaft torque oscillations. To alleviate the torsional toque problem and limit the motor starting current, a continuing air-gap flux using slip frequency management theme is proposed to operate the motor inverter. Simulation results show that the proposed scheme is capable of drastically reducing the torsional torque oscillations and limiting the motor line current to approximately 22p.c of its direct on-line starting value while not prolonging its starting period.