A Robust Two‐Sensor‐Based Fault Diagnosis for Open‐Switch Fault in Power Stage Inverter of BLDC Motor

ABSTRACT Three‐phase inverters frequently experience open‐circuit fault in the phase legs due to the failure of semiconductor devices. This has the potential to disrupt the inverter's motor drive system. This paper presents a comprehensive study of open‐switch faults of IGBT‐based inverters and their consequences on the DC‐link current and neutral point voltage for the Brushless DC motor drive system. The effects of the fault on the input DC‐link current, neutral point voltage, and corresponding rotor position in terms of the sectors (that changes at every sixty degrees) are analyzed, and a relationship between the DC‐link input and motor's stator phase current is determined. Based on the analysis of the DC‐link input current and neutral point voltage in accordance with the sector information, a fault diagnosis method using two electrical sensors is proposed. The proposed diagnosis is a sturdy detection technique that can handle multiple switch faults. It will not generate any false alarm because of any system transients or during phase winding fault condition, making it robust for inexpensive motor drive applications. The simulation analysis is done in MATLAB 2023a, and the experimental analysis has been conducted to validate the theory for the proposed diagnosis.