Stator inter-turn fault detection for seamless fault-tolerant operation of five-phase induction motors

Multiphase motors have been shown to be advantageous in safety-critical and cost sensitive applications due to their ability to operate with open phases. However, for true fault-tolerant operation the motor drive must be able to detect an incipient fault and then transition to post fault operation. It is also desirable for the fault detection method to be non-intrusive and require minimal additional sensing. This paper investigates a low cost diagnostic method using DC voltage injection for monitoring and detection of stator inter-turn faults in five-phase induction motors. The proposed method is incorporated into the control loop and allows the motor to seamlessly transition from healthy to fault-tolerant operation after the fault is detected, with minimal modification to the control logic. It is validated with simulations as well as implemented on a microcontroller and tested on a five-phase induction motor with winding taps to emulate the inter-turn fault condition.