Novel multilevel inverter carrier-based PWM method

Abstract

Abstract — The advent of the transformerless multilevel in-verter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive. Index Terms — Carrier-based pulsewidth modulation, diode-clamped inverter, multilevel converter, multilevel inverter, mul-tilevel pulsewidth modulation. I