The generation of symmetrical space phasors compared with the selective harmonic elimination method of multilevel converters

The basic concept of a multilevel converter is to synthesize a staircase voltage wave-form by the use of several lower voltage DC sources. Capacitors, batteries, fuel cells and photovoltaic modules can be used as DC sources. A multilevel converter has several advantages, like a high voltage quality and low electromagnetic compatibility problems. Two different modulation schemes for multilevel inverters will be analyzed and compared in this paper: The well known selective harmonic elimination method and the generation of highly pulsating space phasors.