A New PWM Technique for Modular Multi-Level Converters: Simulation & Hardware Validation

This paper presents a new pulse width modulation (PWM) technique for a modular multi-level converter (MMC) topology. The presented converter generates a multi-level output voltage with low harmonic distortion, increased reliability, and design flexibility due to the modular nature of the topology. The topology has several sub-modules that can be inserted or bypassed to synthesize large AC voltages. The proposed PWM technique equalizes sub-modules utilization without increasing losses, and retains inherent capacitor voltage balancing. Simulation and hardware results are presented in the paper, which shows that the proposed modulation scheme results in better performance than conventional schemes such as nearest-level modulation, level-shifted carrier PWM, or phase-shifted carrier PWM.