Abstract:
This paper investigates the stator core and winding vibration characteristics of the permanent magnet synchronous generator (PMSG) before and after demagnetization fault. Stator magnetic pull per unit area (MPPUA) and winding electromagnetic force (EF) under normal and fault conditions is deduced, and a simplified forced vibration model of the stator core and end winding is established. The vibration characteristics and amplitude of stator core and winding under single and coupled excitation forces are calculated by finite element analysis (FEA). Experimental verification is carried out. The results indicate that under normal circumstances, the vibration component of the stator core and winding is the double electrical frequency. After the occurrence of local demagnetization fault, fractional-frequency components of
n/
p times the electrical frequency appear in both, and the amplitude of the double-frequency component decreases with the deepening of the demagnetization degree, while the amplitude of the fractional-frequency components increase. In all cases, the vibration amplitudes of the stator and winding under the coupled excitation force are larger than those under a single one, which is more consistent with the experimental situation. However, when analyzing the vibration of the stator, the influence of the winding vibration can be disregarded. When analyzing the vibration of the winding, the influence of the stator vibration needs to be taken into account. The results of this study are still valid when the load changes.