Flying Capacitor Clamped Current Source Inverter with Improved Reliability

Multilevel current source converters (MLCSCs) have garnered increased attention in various applications, and several new topologies have been introduced in recent years. One such topology is the flying capacitor clamped current source inverter (FC3SI). However, akin to traditional CSCs, this topology suffers from the open circuit fault (OCF), which is the most prevalent and destructive fault among these converters. To address this limitation, a novel circuit derived from FC3SI is introduced in this paper, referred to as FC3SI with improved reliability (FC3SI2R). Consequently, the occurrence of OCF in the proposed topology is no longer a concern, even if it happens frequently and simultaneously among all switches. The phase-shifted pulse width modulation (PS-PWM) strategy is employed to achieve natural balancing of the flying capacitors’ voltage. The proposed remedy is both straightforward and effective, and simulation results validate the feasibility of the suggested structure.