Open gate fault diagnosis and tolerant for voltage source inverter fed speed sensorless induction motor drive

Abstract

ABSTRACT This paper presents an effective fault diagnostic and tolerant method for an open-gate fault of a three-phase inverter. The induction motor (IM) drive system is controlled by a speed sensorless indirect rotor field-oriented control (IRFOC). The proposed diagnostic method requires low computation to detect open-gate faults. This method uses a simple direct current technique based on the measured motor currents to detect faulty switch. The fault-tolerant scheme is based on changing the inverter topology from six to four switches to ensure proper operation. In the faulty case, the fault-tolerant technique disconnects the motor phase terminal from the faulty arm of the inverter and connects it to the midpoint of the DC-link via an external switch. The performance of the IM drive is investigated and analysed under normal, faulty and post-fault operations through simulation and experiment. The results demonstrate the effectiveness of the fault diagnostic and tolerant method for retaining almost the normal performance of the IM drive system.