An Extensive Comparison of a Modular Multi-Level Converter Topology with different number of Sub-Modules

An increase in distributed generation and renewable energy in the modern grid has made modular multi-level converters (MMC) very popular. However, renewables demand more energy storage to provide power during faults and uneven energy production from sources like PV and wind. This paper describes an MMC scheme that connects renewables to the grid with minimal filter requirements. The PWM scheme used generates a multi-level voltage output with equal utilization of all the sub-modules, low harmonic distortion, and design flexibility. The later part of the paper compares the MMC topology with a different number of sub-modules. Then, it focuses on energy storage in capacitors with different numbers of sub-modules under different conditions. The stored energy can be useful for fault ride-through during grid fault conditions.