A new switching scheme for reduced switching frequency and balanced capacitor voltages for back-to-back connected, diode-clamped multilevel converters

This paper presents a new switching scheme for back-to-back connected diode-clamped multilevel converters that reduces the devices switching frequency while maintaining capacitor balancing. Comparisons are made between an optimal balancing strategy and a reduced switching strategy with data gathered from a prototype 5-level, back-to-back connected, diode clamped multilevel converter. The proposed scheme is shown to reduce the switching frequency when compared to the optimal balancing case.