Voltage Signature Based Open Circuit Switch Fault Diagnosis Strategy for IM Drives With MPC

Diagnostics of defective leg and switch faults in 3-ph voltage source inverter (VSI) powered induction motor drive system is the primary stage to design the fault-tolerant operation. The preponderance of fault detection techniques largely relies on threshold value-tuning for identifying defective switches. And, using the current component as a variable to determine open circuit switch failure. From this perspective, the article presents an open circuit switch fault diagnosis strategy for 3-ph 2-level VSI. The strategy is based on the estimated phase voltages, which are immune to false alarms caused by transient conditions and parameter fluctuation. An average objective function from the established model predictive current (MPC) control scheme is selected as the fault diagnosis variable to identify the fault in the 3-ph VSI. The polarities of the estimated normalized mean value of inverter voltages are utilized to localize the open circuit switch fault. With the aid of the aforementioned variables, the developed fault diagnosis technique accurately identifies and locates the faulty switches. The voltage signature for the 18 possible combination faults is developed and realized. To assure the reliability of the established fault identification approach, the IM with 2-level VSI is operated with the open fault in different operating conditions in Matlab/Simulink environment and experimentally validated. The hardware experimentation is performed with 2-level VSI and 3.7 kW three-phase IMD.