Broken Rotor Bars Detection in Inverter-Fed Induction Motors Under Continuous Switching of Different Speed Modes

Broken rotor bars (BRBs) fault detection of inverter-fed induction motors operating in a transient regime is difficult, and even more challenging under continuous switching of constant speed, acceleration, and deceleration modes (CADM). In this condition, the BRBs caused amplitude-modulation of fundamental harmonic can be used as a fault indicator. However, the amplitude and frequency of the fundamental harmonic vary widely in continuous switching of CADM, which causes tremendous difficulty in the fault feature extraction. In this article, a novel approach called adaptive window short-time Esprit (AWSTE) is developed to overcome the described problem. It can track the fundamental frequency and extract the envelope of fundamental harmonic under continuous switching of CADM. Experimental results demonstrate the validity of the proposed approach at different control modes, different load levels, and different noise levels.