Advanced Level Shifted Carrier Based Bus Clamping PWM Technique for a 54 Pulse AC to DC Converter Fed MLI Based Induction Motor Drive

Power quality improvement at both grid and motor ends is always an industrial concern for multilevel inverter (MLI) fed induction motor drives. The power quality of an induction motor drive (IMD) is vehemently influenced by the pulse width modulation (PWM) technique of the drive systems. The conventional triangle carrier based level shifted (LS) space vector PWM (LS-CSVPWM) technique provides less power quality problems than the LS sinusoidal PWM (LS-SPWM). In this paper, an advanced LS carrier based bus-clamping PWM (ALS-BCPWM) technique is proposed to mitigate the power quality problems of the IMD systems. The proposed technique utilizes center-aligned harmonic injected saturation LS sinusoidal carriers. In this paper, a 54-pulse AC-DC converter is utilized to feed a 7-level (7L) cascaded H-bridge (CHB) inverter based IMD. The proposed ALS-BCPWM technique employed in CHB inverter's switching reduces the total harmonic distortion (THD) of grid current, stator voltage, stator current, inverter switching and conductor power losses, and torque ripple of the IMD. The performance of the proposed ALS-BCPWM technique for IMD is verified in the MATLAB/Simulink environment and through some preliminary experimental tests.