Carrier interleaved PWM techniques in modular multilevel converters: A comparison based on same voltage level waveforms

Depending on the modulation method the upper and lower arms of the modular multilevel converter are controlled, the topology can generate two different output voltage levels (N+1 and 2N+1) using the same number (N) of sub-modules (SMs). The analysis and evaluation presented in this paper demonstrates that for an output voltage with a given number of levels and same amount of stored energy in the arms, carrier interleaving between the arms of the MMC results in a similar overall performance compared to an MMC without carrier interleaving, despite having less SMs in each arm. The set of presented results complement existing analysis for carrier interleaving applied to MMCs with a given number of SMs per arm. The simulation and experimental results confirm the similar performance of the two configurations and modulation techniques.