Minimization of Torque Ripple in DI-WRIM Drive Through Carrier Interleaving of Stator and Rotor VSIs

In Double Inverter fed Wound Rotor Induction Machine (DI-WRIM) drive, the stator and rotor terminals of the machine are connected to two different Voltage Source Inverters (VSIs). Thus, the ripple into the system is introduced from both the terminals. The expression for torque ripple is derived in terms of the stator and rotor flux ripples introduced from either side. The alternate expressions, obtained in the similar lines of the conventional induction machine, are also presented to validate the expression for torque ripple. Further, to reduce the torque ripple, the effect of carrier interleaving of both the VSIs on the torque ripple, with conventional space vector and advanced bus clamped PWM techniques, is explored in this paper. The reduction in torque ripple with carrier interleaving is validated by analytical, simulation, and experimental results obtained from a 3 kW DI-WRIM drive.