Performance of Modular Multilevel Converter under LS-PWM and NLC Modulation

This paper reports a performance comparison of two different modulation techniques applied to the modular multilevel converter (MMC). Level-shifted pulse-width modulation (LS-PWM) and the nearest level control (NLC) are studied in this work. This comparison focused on total harmonic distortion (THD) of the output current and switching frequency. A three-phase MMC operating as an inverter is modeled and simulated in the Piecewise Linear Electrical Circuit Simulation (PLECS) environment to evaluate the performance of each modulation studied.