Performance evaluation of stator winding fault detection in the inverter-fed permanent magnet machine using high frequency voltage injection

This paper evaluates the fault detection performance of stator winding turn-to-turn short in the inverter-fed permanent magnet (PM) machines based on the high frequency (HF) voltage signal injection. On the basis, a HF pulsating-type AC voltage is injected on the direction of d-axis with respect to the rotor-referred synchronous frame. Once turn short occurs, a fault reflected current signal results due to the change of inductance on the faulty phase. Comparing to prior turn fault detection techniques using synchronized voltage or current signals for the torque production, this HF fault reflected current signal is immune to the speed variation. In addition, the torque load only affects the inductance saturation but not the change of phase and magnitude. It leads to a reduced impact on the load to the HF fault reflected current. It is possible to monitor a minor turn fault (2~3% turn short per phase) at different operating conditions. A salient PM machine with designed turn-to-turn short is built to verify the proposed fault diagnostic method.