Current Sensor Fault-Tolerant Control for Speed-Sensorless Induction Motor Drives Based on the SEPLL Current Reconstruction Scheme

In speed-sensorless-controlled induction motor (IM) drives, current sensors are important but prone to failure, which may significantly degrade control performance. In view of this, this paper proposes a current sensor fault-tolerant control (FTC) scheme for speed-sensorless IM drives. In the proposed current sensor FTC scheme, a single-phase enhanced phase-locked loop (SEPLL) is implemented to reconstruct the faulty phase current without the use of the estimated speed or rotor position. With this, the undesired coupling effects caused by the introduction of estimated speed or estimated position are avoided. Afterwards, with the well-reconstructed current, satisfactory speed and current estimation performance are achieved by the sliding mode observer (SMO) under a current sensor fault. By doing so, the single-phase-current sensor speed-sensorless control of the IM drives can be achieved. A series of experimental tests are executed to verify the effectiveness of the proposed current sensor FTC scheme.