In this article, a fault-tolerant topology of a cascaded H-bridge (CHB) converter is proposed for motor drive applications. Usually, multiwinding transformer fed CHB converters are provided with pre-charge windings for precharging the dc-link capacitors. The windings become inactive after the precharging process. The proposed topology contains redundant cells connected to the precharge windings. After faults in the converter, when the faulty cells are bypassed, the redundant cells can substitute the faulty cells with their power fed from the precharge windings. The aim is to obtain prefault rated line voltages during postfault conditions using the redundant cells. In addition, multiple faulty cells in the same leg or different legs of the converter can be tolerated with the proposed topology. The available power factor range for the proposed topology during most of the multiple fault conditions is improved. The impact of the dc-link voltage of the redundant cells on fault-tolerant capability of the proposed converter is also discussed. To maintain the rated line voltage during postfault conditions, a pulsewidth modulation (PWM) clamping technique is proposed and analyzed in this article. The proposed fault-tolerant topology is verified using computer simulation and experimental results.

中文翻译：

---

使用现有预充电绕组的电机驱动器级联H桥转换器的多种容错拓扑

在本文中，为电机驱动应用提出了级联H桥（CHB）转换器的容错拓扑。通常，由多绕组变压器供电的CHB转换器具有预充电绕组，用于对dc-link电容器进行预充电。在预充电过程之后，绕组将变为非活动状态。提出的拓扑包含连接到预充电绕组的冗余电池。在转换器发生故障后，当故障单元被旁路时，冗余单元可以用预充电绕组提供的功率代替故障单元。目的是使用冗余单元在故障后的情况下获得故障前的额定线路电压。另外，转换器的相同支路或不同支路中的多个故障单元可以被所提出的拓扑所容忍。在大多数多重故障情况下，针对建议拓扑的可用功率因数范围得到了改善。还讨论了冗余单元的直流链路电压对所提出的转换器的容错能力的影响。为了在故障后条件下维持额定线路电压，本文提出并分析了脉冲宽度调制（PWM）钳位技术。利用计算机仿真和实验结果验证了所提出的容错拓扑。