Speed Sensor Fault-Tolerant Controller for Induction Motor Using New Minimum Probability Voter Based on Signal Strength

A speed sensor fault-tolerant back-stepping controller with a new minimum probability voter based on signal strength (MPVSS) has been introduced in this paper. The major goal of MPVSS is to detect and to reconfigure the induction motor control in case of speed sensor failure (intermittent disconnection of an incremental encoder) using sliding mode observer for low speed estimation and extended Kalman filter for medium and high speed estimation. Here, the proposed MPVSS enjoys the feature of insensitivity to rotor resistance variations and easiness to set its threshold. In fact, signal strength plays an essential role in releasing the designer from severe constraints imposed by selecting a correct voter threshold. Simulation results show the efficiency of the suggested method. Besides, the superiority of the presented approach has been confirmed by comparing its performance with a maximum-likelihood voting algorithm.