Second-order Sliding Mode based Sensor Fault-Tolerant Control of Induction Motor Drives

This paper presents a fault-tolerant control method for induction motor (IM) based on higher order sliding mode (HOSM) observer. Traditional current control involves the regulation of the d - q synchronous reference frame currents with or without a decoupling compensator. The compensation voltages, which require speed and motor parameters cancel the coupling terms. When the speed is not available, this approach leads to a degraded performance of the controller. In the proposed scheme, a HOSM observer is designed to estimate the compensation voltages, which further estimates the motor speed through algebraic calculations. The estimated speed is then employed as feedback when speed sensor is faulty. Simulations on a 1/4-hp three-phase IM highlights the performance of the proposed approach.