Comparison of Medium-Voltage cascaded H-bridge inverter and Hexagram inverter for motor drive applications

This paper describes the design of 1MVA 4.16kV Medium-Voltage motor drive using Hexagram inverter, and is compared to Cascaded H-bridge inverter motor drive system. System design and component selection is elaborated for motor drive system using both topologies. Power loss and reliability is also estimated for comparison purpose. Fault tolerant control is a feature for both motor drive system and is discussed and compared in detail. From the comparison, hexagram inverter appears more advantageous because of less DC bus storage requirement, higher reliability, higher efficiency and simple control.