On the Effect of Position Signal Error on the Performance of Single-Phase BLDC Drives

Single-phase brushless DC machines are widely used for automotive auxiliary drives for pump and fan applications due to their low cost. These drives typically utilize a Hall-effect sensor for providing position information for motor control. However, due to inherent manufacturing imperfections, the position signal may be misaligned from the zero-crossing points of the back-EMF, which can affect the switching angles and overall performance of the machine. In this paper, experimental analyses are conducted on 56 single-phase BLDC fan drives to assess the error of the position signal and its impact on efficiency and structure-borne noise. The results indicate that although the position signal error slightly reduces the drive’s efficiency, it significantly increases vibration at the critical frequency.