High-resolution low-cost rotor position sensor for traction applications

The paper presents for the first time the use of a low cost Hall effect position sensor for a synchronous reluctance machine (SynRM). The use of vector control for a SynRM requires information of the rotor position. Already the SynRM is independent of the use of permanent magnets (PMs) which results in reduced cost of the SynRM. Hence the use of a low cost position sensor contributes to an additional cost reduction of the electric drive for traction applications. The paper also presents a comparison between the low cost position sensor with the digital hall effect position sensor used in the electric power steering (EPS) machines. The different dynamics of the SynRM were demonstrated through the use of the low cost position sensor. The low cost position sensor had a relatively simpler algorithm for position information and better position resolution. Through the use of the low cost position sensor the machine produced low torque ripples of less than 9% with a total current harmonic distortion (THD) of less than 2%. The proposed position sensor registered an error less than 1 mechanical degree when compared with a 12-bit industrial encoder.