Robust FDI Scheme in Power Actuators for Induction Motor

In this paper a robust model-based FDI scheme for actuator faults in induction motor (IM) drives is presented. A voltage source inverter is studied as power actuator for the induction motor. Residuals are synthesized by applying a differential geometry approach. In order to obtain a robust observer-based FDI scheme a bank of PI-observers is used, which according to the fault time profile allows to identify the faults. Departing from the results in Espinoza et al. [2008], the diagnosability and decoupling conditions for actuator faults are satisfied in the IM model. In this way, residuals are decoupled from the load torque and operating conditions, and simultaneous faults can be addressed. Hence, in order to isolate faults related to switching devices, it is suggested a directional residual evaluation. Hence 3 residuals are constructed to isolate the faulty switches. The ideas presented in the paper are verified experimentally in a test-bench of 1 HP induction motor under single and simultaneous faults.