Position Signal Compensation Control Technique of Hall Sensor Generated by Uneven Magnetic Flux Density

Abstract

Generally, brushless dc (BLDC) motor control uses a 120 degrees conduction method that utilizes a low-cost Hall sensor as a position sensor. However, because of the mounting position error of the Hall sensor and the uneven magnetic flux density of the rotor, an erroneous position signal may be output, which will adversely affect the BLDC motor control. Therefore, this paper analyzes the abnormal electric current section that occurs due to the position error of the Hall sensor and the uneven magnetic flux density. Subsequently, the error is derived from the analyzed phenomenon as a formula. The compensation control algorithm to overcome the control problem due to this error is studied, and a method to maintain an accurate energization interval is suggested. Further, it is shown through experiments that the quantitative analysis of the error using the proposed compensation control algorithm is valid.