Investigation of the effects of stator short circuit faults on permanent magnet synchronous motor performance

In recent years, permanent magnet synchronous motors (PMSM) have been widely used especially in electric vehicle applications, industrial and other fields. The operating life of motors used in such critical applications depend on running as healthy. It is very important that knowledge of the impact of faults in motors and early detection of faults. Short circuit faults that originated from stator winding insulation failure are one of the most frequent fault types in electrical machines. A type of motor that is commonly used especially in applications requiring precise speed and position control, permanent magnet synchronous motor, short circuit failures that may occur in the stator, may not be noticed if the fault is in small proportions. Failures that occur will grow and produce unexpected results. Therefore, analysis the effect of stator short circuit fault on motor performance is very critical and important. In this thesis study, it has been investigated that the effects of stator winding inter-turn short circuit fault on vector controlled surface-mounted permanent magnet synchronous motor's performance. For this purpose, healty and faulty simulation models of motor were created in Matlab/Simulink software using the faulty and healthy state equations of the motor. The short-circuit failure severity of 2%, 12.5% and 25% in the single phase of the stator of the PMSM were generated via a simulation model that could be adjusted with respect to fault severity. The results obtained from the simulated model for the healthy condition of the same motor were compared with the results obtained in the case of the faulty. In the simulation model, it was observed that the oscillations in the torque of the motor increased in parallel with the increase of the short circuit fault severity. In the same way, the amplitude of the faulty phase current of the motor with a short circuit is increased due to the increase in the short circuit fault intensity. This causes PMSM to draw more current from the network under the same load. The same conditions as in the simulated model were also carried out in the experimental work. The results obtained from the experimental work and the results obtained from the simulation model are compared. The results obtained from the experimental study and simulation model showed that inter-turn short-circuit failure reduced motor performance. In both simulation model and real-time application, a fast Fourier transform (FFT) was applied to moment data in a wide range of speeds and loads, analyzing moment data in frequency plane, trying to detect harmonics dependent on inter-turn short-circuit failure.