Sensorless speed control of VSI-FED induction motor drive under IGBT open-switch damage: Performances and fault tolerant analysis

This paper describes a remedial strategy against open-circuit fault occurring in the inverter switching devices of a sensorless induction motor drive. These applications are much more sensitive to inverter faults that the conventional sensored systems. Hence, if the fault is not quickly detected and compensated, it can leads to hard failure and to disconnecting the system. A way of maintaining its functionality is to introduce a fourth inverter pole, with the same topology and capabilities of the other conventional three poles. The fault tolerance is evaluated and verified using sensorless vector control of a three phase induction motor based on Luenberger observer (LO). The post-fault robustness and performance is the same as the normal operation because of the fast fault detection and reconfiguration. The output line-to-line voltages of the inverter are used for the FDI process. The results are presented and discussed to evaluate the Luenberger observer operating under considered faults.