Static eccentricity fault detection of the BLDC motor inside the air handler unit (AHU)

Because of the wide range of application of BLDC (brushless DC) motors, the fault diagnose of BLDC becomes an essential problem. For those BLDC motors in application, rotor faults account for most of the faults in BLDC motors. Static eccentricity and dynamic eccentricity are two of the main faults in the rotor of BLDC motor. In this paper, an improved method detecting static eccentricity is proposed based on the comparison between the positive sequence current and negative sequence current. Comparing to the traditional method which only focuses on the change of the negative sequence of fundamental frequency current, the method proposed in this paper could be more reliable since the positive sequence current and harmonics current are considered as well. A BLDC motor with static eccentricity in AHU (air handler unit) will be tested. The effectiveness and availability are verified in both simulation and experiment results.