A comparative simulation study of the three level-shifted multicarrier PWM strategies used to control a modular multilevel converter (MMC): Phase Disposition (PD), Phase Opposition Disposition (POD), and Alternate Phase Opposition Disposition (APOD). In level-shifted multicarrier PWM, one sine reference is compared against several vertically stacked triangular carriers (one per voltage level); PD, POD, and APOD differ only in the relative phase/polarity of adjacent carrier bands. Using a single-phase half-bridge-submodule MMC modeled in MATLAB/Simulink, the study drives each strategy and measures the resulting load-voltage and load-current quality via total harmonic distortion (THD). The takeaway is the comparative ranking of the dispositions by output power quality for an MMC, with phase-disposition (PD) PWM yielding the lowest-THD, cleanest waveform. It is an engineering evaluation of existing modulation schemes rather than a new modulation algorithm.
This applied power-electronics paper (Saradva, Matnani, Trivedi; IJIRT 2018) compares level-shifted multicarrier pulse-width-modulation (PWM) strategies for a modular multilevel converter (MMC). An M…