Current Sensor Fault Detection and Fault-tolerant Control of Bearingless Induction Motor Based on VCS

Abstract

To ensure the normal operation of a control system for a bearingless induction motor (BIM) after current sensor failure, a virtual current sensor (VCS) fault-tolerant control strategy was proposed. First, on the basis of the coordinate transformation of the stator current of the torque winding, the fault detection marks were set to realize current sensor fault detection. Second, according to the mathematical models of BIM, the stator current differential equations included in the VCS were derived, and the solutions of the equations were used as the reconstruction current of the fault current sensor, achieving fault-tolerant operation control after the sensor fault. The simulated and experimental results show that the set fault detection marks can realize the quick and accurate identification of sensor faults, and the estimated current from the VCS output can replace the faulty current after the current sensor fails, and the stator current can be reconstructed effectively under no-load, load change, and speed change conditions, and also ensure a good suspension of the motor rotor under sudden addition of disturbance condition.