A residual current-based indicator for early detection of stator winding faults in synchronous reluctance machines

The early identification of inter-turn short-circuit faults (ITSCFs) in electrical machines has become a priority due to their detrimental influence on reliability and efficiency.However, achieving accurate detection under closed-loop control remains challenging.Conventional second-harmonic-based methods are highly dependent on electromagnetic torque and machine parameters, reducing robustness.This study proposes a parameter-independent fault indicator for synchronous reluctance machines (SynRMs) based on the residual difference between measured and reference dq-axis currents.Simulation results demonstrate that the proposed indicator amplifies the fault-related second harmonic up to 0.47 p.u., compared to less than 0.01 p.u. in conventional dq products.Under both steady-state and transient conditions, the method successfully detects weak faults (μ = 4%) and severe faults (μ = 16%) with a short detection delay of approximately 0.038 s, while remaining insensitive to load torque variations up to 14 N•m and speed changes from 400 to 1500 rpm.The approach eliminates torque dependence and parameter sensitivity, providing a robust and computationally efficient framework suitable for real-time predictive maintenance applications.