Fault detection of synchronous motor inter-turn short circuit based on current residual harmonic characteristics

Inter-turn short circuit (ITSC) faults in the stator winding of permanent magnet synchronous motors (PMSM) are highly prevalent and can cause significant damage to both the windings and permanent magnets. Early detection of ITSC faults is challenging due to weak fault signals that are easily masked by noise and the complex operating conditions of PMSM, which result in significant fluctuations in fault characteristics. To address these challenges, this paper proposes a novel ITSC fault diagnosis method based on the second-harmonic features of dq -axis current residuals. A new fault detection index ( FI ) is introduced to sensitively identify early ITSC faults while demonstrating robustness against variations in speed and load. Additionally, an effective time-frequency domain extraction method, Multisynchrosqueezing Transform (MSST), is proposed to accurately extract fault features from multi-component signals, even under low signal-to-noise ratio (SNR) conditions. The MSST effectively captures the time-frequency ridges of signals, showcasing superior time-frequency aggregation performance. Experimental results validate the method’s efficiency and accuracy in detecting ITSC faults across variable operating conditions. This approach offers a significant advancement in PMSM fault diagnosis, with notable innovative value and practical application potential.