A novel arithmetic based on coordinate transformation for sensorless brushless DC motor drives

摘要

This paper presents a novel method for sensorless BLDC motor drives, which is based on coordinate transformation, in order to compensate the rotor position detection error caused by the first-order low-pass filter over wide speed ranges. Two coordinate systems are defined, which are named as ‘a’ and ‘b’. For compensating the error, the angle β, which is between ‘b’ coordinate system and ‘a’ coordinate system, is controlled in real time, and the zero-crossing timing of reconstructed position signal, which is the projection on ‘b’ coordinate system from ‘a’ coordinate system, is just the phase commutation timing. The rotor position detection error is analyzed and experimental results verify the analysis and demonstrate advantages of the new arithmetic.