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In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology. An open-switch fault in the NPC rectifier of the back-to-back converter leads to the distortion of the input current and torque vibration in the system. Additionally, an open-switch fault in the NPC inverter of the back-to-back converter causes the distortion of the output current. Furthermore, the WTG system can break down in the worst case scenario. To improve the reliability of WTG systems, an open-switch fault detection method for back-to-back converters using the NPC topology is required. This study analyzes effects of inner and outer open-switch faults of the NPC rectifier and inverter and describes a novel open-switch fault detection method for all possible open-switch faults in the back-to-back converter. [ABSTRACT FROM AUTHOR]

This paper presents a fault identification and tolerant method for switched reluctance motor (SRM) drives. The reliability of a power transistor in a power converter is the source of most problems in several industrial applications. It is critical to correctly diagnosis the faults occurring in a drive system to avoid harmful accidents and to ensure continuity of operation. In this paper, two types of faults, namely, short- and open-circuit faults, are analyzed on the basis of the current patterns of the power transistors of SRM drives. A fault is detected when the measured amplitude of the current differs from that of the normal-state current. A fault-tolerant scheme is applied according to the type of fault. Simulations and experiments are performed on a 1.0-kW SRM drive. The results are presented to verify the validity of the proposed method. [ABSTRACT FROM PUBLISHER]