Capacitor balance issues of the diode-clamped multilevel inverter operated in a quasi two-state mode

A new operational mode for diode-clamped multilevel inverters termed quasi two-level operation is proposed. Such operation aims to avoid the imbalance problem of the dc-link capacitors for multilevel inverters with more than three levels and reduces the dc-link capacitance without introducing any significant voltage ripple at the dc-link nodes. The proposed operation can be generalized for any number of levels. The validity of the proposed multilevel inverter operational mode is confirmed by simulations and experiments on a prototype five-level diode-clamped inverter.