Harmonic Analysis of Quasi-2-Level Medium Voltage Super-Switch

This article focuses on the harmonic analysis of the quasi-2-level super-switch (Q2L SS), considering different delay times and the number of steps. The harmonic performance is investigated in-depth using double fourier integral transformation analysis, simulations, and experiments. According to the analysis, increasing the number of steps facilitates a smoother transition between the negative and positive states of the output voltage. As a result, the harmonic performance of the Q2L SS is significantly improved. On the other hand, an increased number of steps sets the boundaries to the switching frequency and the maximum modulation index. Moreover, multistep Q2L SS requires more capacitors, which can significantly increase the volume of the converter. The study establishes the ground basis for understanding the Q2L SS operation in the harmonic domain. It can be used for the future research in the domain of Q2L SS and approaches for designing EMI filters for Q2L SS-based converters.