A Fault Diagnosis and Fault-Tolerant Control Method for Current Sensors in Doubly Salient Electromagnetic Motor Drive Systems

This article proposes a fault diagnosis and fault-tolerant control method for three fault modes of current sensors in the doubly salient electromagnetic motor (DSEM) drive system, namely signal loss, gain variation, and zero offset. First, the fault features of current sensors under different fault modes are extracted based on the variation characteristics of three-phase currents in different working sectors to locate and distinguish the fault. Then, a fault-tolerant control method for current sensors is developed to reconstruct the fault phase current under the signal-loss fault and compensate the current online under the gain-variation and zero-offset faults, based on the remaining healthy phase currents and estimated fault coefficients. The proposed method only requires information of three-phase currents and the rotor position, instead of an accurate system model, and immunizes the variation of load and field current, having the advantages of simple implementation and superior robustness. Both simulation and experimental results verify the effectiveness of the proposed method.