Performance evaluation of half-bridge cascaded multilevel converters operated with multicarrier sinusoidal PWM techniques

Abstract

High-power high-voltage power electronics systems with fully-controlled semiconductors can benefit from the development of modular solutions based on voltage-sourced building blocks. This paper offers a performance comparison of various multicarrier sinusoidal pulse width modulation (PWM) techniques for the control of the modular multilevel converter (MMC) based on the half-bridge capacitor cell. It is found that the PWM method can significantly affect the ripple of the capacitor free DC-bus, hence the selection of the carrier frequency and the multi-carrier PWM method is an important design question for the MMC topology. Simulation results for a three-phase rectifier-inverter system generated with the PSCAD/EMTDC software package are provided to support the theoretical considerations.