Extendable space-type switched-capacitor multilevel inverter with fault-tolerant capability

Low reliability is one of the main concerns in terms of multilevel inverters (MLI) due to the presence of a large number of switches and capacitors. Therefore, the fault-tolerant operation of MLIs has recently gained a great deal of attention. An extendable space-type switched-capacitor MLI topology with fault-tolerant characteristics is proposed in this paper. The proposed inverter employs a single direct-current voltage source and three capacitors to output staircase voltage levels with low distortion. The proposed topology is capable of tolerating open-circuit faults due to the separated charging paths of the inverter. Under pre-fault and post-fault operations, it preserves capacitor voltage balancing, voltage boost capability, as well as the ability to supply inductive loads. Furthermore, the voltage stresses of the switches and the voltage ripples of the capacitors are decreased or remain under post-fault operations. The proposed topology has been validated with a laboratory prototype in both dynamic and steady-state operations