A simultaneous detection and tolerant control method for current- and speed-sensor faults in induction motor

To enable simultaneous fault detection and fault-tolerant control for current sensor (CS) and speed sensor (SS) in induction motors (IMs), this article proposes a novel method based on a reduced-order sliding mode observer (SMO). First, a model of the IM system incorporating CS and SS faults is established, and an augmented system is constructed through state augmentation. Then, a system transformation is applied to achieve complete decoupling of the sensor fault variables from the state variables, and a novel reduced-order SMO is designed for the decoupled system. Subsequently, accurate fault detection is performed using the fault estimates obtained from the observer. Fault-tolerant control for the CS and SS is then realized by compensating the measured values with the estimated faults. Finally, experimental verification is conducted on a hardware-in-the-loop (HIL) platform. The results demonstrate the effectiveness of the proposed method in detecting and implementing fault-tolerant control for single CS or SS faults, simultaneous CS and SS faults, and multiple CS faults. Additionally, the method shows robust performance under adverse conditions, such as dc-side voltage fluctuations and sudden load torque variations.