A Simple Strategy for DRFOC of 3-phase Induction Motors under Single-phase Open Fault

This research investigates a simple method for Direct Rotor Field-Oriented Control (DRFOC) of star-connected 3-Phase Induction Motor (3Ph IM) drives under Single-Phase Open Fault (SPOF). The proposed control scheme includes a modified RFOC strategy in cooperation with a flux linkage observer. Most studies on this topic are intended for Indirect Rotor Field-Oriented Control (IRFOC), and hence are not appropriate at low speed operation due to using a pure integration for the flux angle calculation. To this end, a rotor flux linkage observer is designed which alleviates the speed and torque ripples of the faulty motor during low speed operation. The observer is capable of estimation of the rotor flux during healthy and SPOF conditions by only some modifications in the 3Ph IM parameters. The proposed DRFOC approach is tested under different conditions and the effectiveness of the proposed system is confirmed by experimental results. The results show the good fault tolerant capability and tracking performance of the proposed controller during different speeds.