A comparison of tri-level and bi-level current controlled grid-connected single-phase full-bridge inverters

The performance of current-controlled single-phase full-bridge tri-level and bi-level grid-connected inverters is discussed in this paper. A comparative evaluation is made against identical inverters to demonstrate the advantages of tri-level inverter systems. Several parameters have been selected for comparison, such as instantaneous inductor current and its associated error, the instantaneous switching frequency, the inductor input voltage and the magnitude spectrum of the inductor current. It is revealed through extensive simulations that the tri-level approach is far superior than the bi-level counterpart.