ABSTRACT

In this paper, some recently proposed multilevel power converters are investigated for their fault-tolerant capabilities and improved reliability. These reported topologies are generally reduced device multilevel inverter (RD-MLIs) configurations that cannot tolerate switch failures due to absence of redundant states. Present work therefore aims to incorporate open-circuit fault-tolerant capability by adding few redundant states in switching sequences of existing topologies. The work in this paper objectively presents two existing topologies of five-level and seven-level Multi-Level Inverters (MLIs) modified for fault-tolerant (FT) capability against single switch open-circuit (OC) faults. The modification for fault-tolerant feature (FT-MLI) has intrinsic self-voltage balancing capability, low cost and control simplicity. The modified FT-MLI uses multi-carrier sinusoidal pulse-width modulation (SPWM) technique to generate control switching pulses as per desired switching sequences. Simulation and experimental results of these modified FT-MLI topologies under healthy, faulty and post-fault mode are presented and discussed. Experimental results verify the feasibility and effectiveness of these modified FT-MLI topologies which are suitable for safety-critical applications.

摘要

在本文中，研究了一些最近提出的多电平电源转换器的容错能力和提高的可靠性。这些报告的拓扑通常是简化的设备多电平逆变器 (RD-MLI) 配置，由于没有冗余状态，无法容忍开关故障。因此，目前的工作旨在通过在现有拓扑的开关序列中添加少量冗余状态来整合开路容错能力。本文中的工作客观地提出了两种现有的五电平和七电平多电平逆变器 (MLI) 拓扑结构，它们针对单开关开路 (OC) 故障进行了容错 (FT) 能力修改。容错特性的修改（FT-MLI）具有固有的自电压平衡能力、低成本和控制简单性。改进后的 FT-MLI 使用多载波正弦脉宽调制 (SPWM) 技术根据所需的开关序列生成控制开关脉冲。介绍和讨论了这些改进的 FT-MLI 拓扑在健康、故障和故障后模式下的仿真和实验结果。实验结果验证了这些适用于安全关键应用的修改后的 FT-MLI 拓扑的可行性和有效性。