1 The Faculty of Engineering and Science (ENG), Aalborg University2 Power Electronic Systems, Department of Energy Technology, The Faculty of Engineering and Science, Aalborg University3 Department of Energy Technology, The Faculty of Engineering and Science, Aalborg University4 Ajou University
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.
I E E E Transactions on Industry Applications, 2015, Vol 51, Issue 1, p. 325-335