A New Level Shifted Carrier Based PWM Technique for a Cascaded Multilevel Inverter Based Induction Motor Drive

The pulse width modulation (PWM) techniques are becoming the game changer for multi-pulse power converter fed multilevel inverter-based induction motor drive (IMD) due to their significant impacts on power quality. In this article, a new level shifted carrier-based PWM technique is proposed for a 5-level cascaded H-bridge (CHB) multilevel inverter driven by a 36-pulse ac-dc converter based IMD. To meet the power quality demand of IEEE-519 at grid side, a modular transformer is used, and the transformer is coupled to form a 36-pulse ac-dc converter. A 5-level CHB multilevel inverter is utilized on the motor side, which uses the proposed carrier based PWM technique for switching action to ensure superior performance of the IMD. The proposed PWM technique is named as third-harmonic injected inverted sinusoidal carrier PWM ((THISCPWM)-S-2), which utilizes 3(rd) harmonic injection principle with inverted sinusoidal signal to form the proposed carrier signal. The 5-level CHB inverter used in the IMD shows less power loss and total harmonic distortion (THD) with the proposed (THISCPWM)-S-2 technique. Moreover, the IMD with the (THISCPWM)-S-2 shows low stator voltage THD, stator current THD, and smooth dynamic response. Apart from these, the (THISCPWM)-S-2 mitigates the torque ripple of the IMD. The motor drive system with the (THISCPWM)-S-2 technique is modeled and its performance is simulated on MATLAB/Simulink environment. A scaled down experimental setup is utilized to validate the superiority of the proposed PWM technique.

Automated summary

This article proposes a new level shifted carrier-based PWM technique named (THISCPWM)-S-2 for a 5-level cascaded H-bridge multilevel inverter driven by a 36-pulse ac-dc converter based IMD. The technique utilizes third-harmonic injection principle with inverted sinusoidal signal to form the carrier signal, resulting in improved power quality, reduced harmonic distortion, and mitigated torque ripple.