In this paper, the remedial operation of switch faults will be investigated comprehensively for T-type-three-level-inverter-fed dual three-phase motor drives. The open-circuit switch faults in multiple phase legs are discussed at first. The faulty conditions are classified into five categories. Different remedial strategies, namely Type-I to Type-V schemes, are proposed for different faulty conditions. In particular, three kinds of Type-III fault-tolerant control schemes are proposed by using medium-voltage vectors to synthesize small-voltage vectors, in such a way that the mid-point voltage in a dc link can be stabilized well. Then, the short-circuit faults in both clamping switches and half-bridge switches are investigated. By analysis, their operation conditions are equivalent to conditions loss of both P and N voltage levels and open-phase faults, respectively. Thus, the corresponding remedial strategies can be applied accordingly. Particularly, a voltage compensation control method is proposed for conditions, where open-switch faults coexist with open-phase operation induced by short-circuit faults in half-bridge switches. The validity of all of theoretical analysis and the proposed remedial strategies has been verified by experiments.

中文翻译：

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T-3L逆变器供电的双三相永磁同步电机驱动开关故障整治综合研究

本文将对T型三电平逆变供电双三相电机驱动的开关故障修复操作进行综合研究。首先讨论多相桥臂的开路开关故障。故障条件分为五类。针对不同的故障条件提出了不同的补救策略，即 Type-I 到 Type-V 方案。特别是提出了三种Type-III容错控制方案，利用中压矢量合成小电压矢量，能够很好地稳定直流环节的中点电压。然后，研究了钳位开关和半桥开关中的短路故障。通过分析，它们的运行条件分别相当于 P 和 N 电压电平丢失和缺相故障的条件。因此，可以相应地应用相应的补救策略。特别地，针对半桥开关短路故障引起的开路故障与断相操作共存的情况，提出了一种电压补偿控制方法。所有理论分析和提出的补救策略的有效性已通过实验得到验证。