A Modified Level-Shifted PWM Strategy for Fault-Tolerant Cascaded Multilevel Inverters With Improved Power Distribution

• Published in: IEEE transactions on industrial electronics (1982) Vol. 63; no. 11; pp. 7264 - 7274
• Main Authors: Kim, Seok-Min, Lee, June-Seok, Lee, Kyo-Beum
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-11-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cascaded H-bridge multilevel inverter; Fault tolerance; Fault tolerant systems; Inverters; level-shifted pulse width modulation; neutral shift; Pulse width modulation; Switches; Topology
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2016.2547917

To increase the fault tolerance for cascaded H-bridge multilevel inverters (CHMIs) based on level-shifted pulse width modulation (LS-PWM), a modified LS-PWM method is proposed for the inverters operating under faulty conditions. To cover both open- and short-device fault cases, two types of switching scheme are included in this PWM method. With this PWM method, the neutral shift can be applied as fault-tolerant control for CHMIs based on LS-PWM. Finally, three-phase-balanced line-to-line voltages and currents with minimum harmonic distortion are produced for the inverter with disabled power cells. In addition, this LS-PWM method has the capability to improve power distribution among the H-bridge power cells under the faulty conditions. Simulation and experimental results show that the proposed PWM method performs satisfactorily to achieve fault tolerance.