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Journal of Control Science and Engineering
Volume 2018 (2018), Article ID 5126404, 9 pages
Research Article

Fault-Tolerant Control Strategy for Neutral-Point-Clamped Three-Level Inverter

Engineering Research Center of Internet of Things Technology Applications of Ministry of Education, Jiangnan University, Wuxi 214122, China

Correspondence should be addressed to Yanxia Shen and Beibei Miao

Received 15 September 2017; Accepted 31 December 2017; Published 1 February 2018

Academic Editor: Ahmed Rhif

Copyright © 2018 Yanxia Shen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A fault-tolerant control technique is discussed for the Neutral-Point-Clamped (NPC) three-level inverter, which ensures that the NPC inverter operates normally even under device failures. A two-level leg is added to the NPC inverter; when the device open circuit fault occurs, the load of this faulty phase is connected to the neutral point of this two-level leg through the bidirectional thyristors. An improved Space Vector Pulse Width Modulation (SVPWM) strategy called “addition and subtraction substitution SVPWM” is proposed to effectively suppress fluctuation in capacitor neutral-point voltages by readjusting the sequence and action time of voltage vectors. The fault-tolerant topology in this paper has the advantages of fewer switching devices and lower circuit costs. Experimental results show that the proposed fault-tolerant system can operate in balance of capacitor neutral-point voltages at full output power and the reliability of the inverter is greatly enhanced.