Open-Switch Fault Tolerance Strategy for Induction Motor Drive System

Abstract

Voltage source inverters (VSIs) based on insulated-gate bipolar transistors (IGBTs) may face various faults that can affect the operation and safety of the entire electric drive system. To enhance the reliability of the drive system, it is crucial to develop an accurate fault diagnosis (FD) method and increase fault tolerance control (FTC) capabilities. This paper provides a novel FTC strategy for IGBT open circuit fault (OCF) in induction motor (IM) drives. The proposed FTC strategy includes a fault diagnosis algorithm and inverter reconfiguration. A three-phase current-based diagnosis method (FD) is adopted in this research, where the average absolute value of the normalized currents is used to extract fault detection variables. The developed FD method does not need any extra sensors and provides fast diagnosis time, which is equivalent to almost 25-30% of the phase current's fundamental cycle. To accomplish satisfactory post-fault operation of the IM drive, a four-leg inverter topology is employed. Finally, the effectiveness of the proposed fault-tolerant drive and diagnosis method is proven through various simulation results.