DC link balance and comparison of the symmetrical hybrid multilevel inverter

The newly introduced symmetrical hybrid multilevel (SHM) inverter is analyzed in this paper. Topics covered in this study include a brief presentation of the topology, DC link voltage balance and a comparison with other multilevel topologies by means simulations. Part count, loss distribution and installed switch power are considered. Experimental results of the DC link balance in a 300 W/200 Vdc 1-phase prototype are exposed. Results indicate a naturally balanced voltage in the DC link capacitors, a rather simple topology compared to other 5-level converters and the highest efficiency among the analyzed converters for line voltages of 6 kV at switching frequencies under 750 Hz.