Operation of an induction motor with an open circuit fault by controlling the zero sequence voltage

This paper presents a fault ride through method for use when open circuit winding faults appear on an induction motor drive. A feed forward compensation term is introduced into the zero sequence component of the dq reference voltages which considerably reduces current and torque ripple in the faulted motor drive. If the machine's ldquoneutral pointrdquo voltage can be modulated, then a reasonably high speed can be achieved before field-weakening control is required. The paper describes the application of the control method to a delta-connected machine with an open winding fault, with an unmodified inverter drive. The proposed scheme has been verified by experimental results.