Multiple IGBTs open circuit faults diagnosis in voltage source inverter fed induction motor using modified slope method

This paper deals with multiple insulated gate bipolar transistor (IGBTs) open circuit faults detection and localization in a pulse width modulation (PWM) voltage source inverter (VSI) fed induction motor based on a modified slope method. Firstly, a detection algorithm was used to calculate the slope of the current-vector trajectory in complex plan αβ. This algorithm detects the faulty bridge. Second, the Schmitt-trigger is used for the phase's currents monitoring. This circuit determines the phase's currents polarity and detect whether the current in the faulty arm is positive or negative. The analysis of two combined information makes it possible to diagnose the two simultaneous IGBTs open circuit fault within inverter. The proposed technique is developed and implemented to vector control induction motor drives. An experimental setup in the laboratory is used to compare the simulation results and the experimental results and to evaluate the performances of the proposed method.