A five-level zero average current error controlled single-phase grid-interactive inverter

For inverters, power quality is generally measured in terms of harmonic content and the magnitude of the ripple current. Current ripple for a conventional inverter is a function of inductor size, switching frequency and the number of discrete DC input levels (multilevel inverter). Zero average current error (ZACE) control provides low line frequency harmonics but requires high switching or a large inductor to provide low current ripple since only bilevel control is available. Modification of the ZACE concept is required to handle multilevel inverters. A new ZACE method is proposed that can handle the voltage transition in a single-phase multilevel inverter. Simulation results are presented for a grid-connected single-phase five-level inverter to demonstrate the concept.