An H8 Current-Source Inverter using Wide Bandgap Bidirectional Switches

Conventional current-source inverters (CSIs) using reverse-voltage-blocking (RB) switches typically suffer efficiency penalties due to the high forward voltage drop of RB switches. In contrast, monolithic bidirectional (BD) switches have RB capability but with lower conduction loss than RB switches, making them more appealing candidates for CSI switches. This paper describes how implementing BD switches in CSIs creates challenges including more complicated commutation schemes, more gate control signals, and tradeoffs between switching and conduction losses. To address these issues, a new CSI topology (H8-CSI) that is tailored for using wide bandgap (WBG)-based BD switches is proposed. In addition to reducing the CSI's conduction loss by using BD switches, the H8-CSI achieves both zero-voltage switching and zero-current switching for most of its switches that further reduces the CSI's loss. Analysis, simulation, and experimental results confirm the advantages of the H8-CSI topology over the conventional CSI topology using either RB or BD switches.