A Diagnosis Method for Inverter Open-circuit Faults of Brushless DC Motor Driver Systems

Inverter fault diagnosis is the premise of the fault tolerance control,which is helpful to improve the reliability of motor driver systems.This paper presented a novel diagnosis method for the inverter open-circuit fault of brushless DC motor(BLDCM) driver systems in high side pulse width modulation-low side on(H_PWM-L_ON) modulation mode.In the proposed method,the difference of line voltages during the PWM_ON and PWM_OFF time was considered as the fault feature to detect the open-circuit fault,and in the next working mode of the inverter,the faulty switch could be identified.In order to reduce application cost,this paper designed a circuit,as well as the corresponding software algorithm,to get the difference of line voltages by sampling the terminal voltages.The maximum diagnosis time is no less than one electrical period.This method has the features of a simple circuit,convenient implement,high reliability,low cost,and is immune to closed-loop or open-loop control strategies.The experiment results verified the effectiveness of the proposed method.