Modeling and manufacturing error analysis of a magnetic off-axis rotor position sensor for synchronous motors

Čorović, Selma (author), Ambroželi, Kris (author), Manko, Roman (author), Miljavec, Damijan (author)

In the vehicle electrification sector, the precise and reliable control of e-motors is of the utmost importance for ensuring the efficient and safe operation of the whole electric vehicle drivetrain. Specifically, the assessment of the absolute rotor position of the permanent magnet-based synchronous motors is necessary for precise e-motor control, which is strongly determined by the precision of the sensing device used for the absolute rotor position assessment. Magnetic rotational position sensing devices/encoders are predominantly used in the automotive sector. The accuracy of a magnetic-based rotational position sensing device can be affected by defects/errors which may occur during its manufacturing and/or assembly process. These defects may in turn affect the accuracy of the e-motor’s control and operation. The primary objective of this study was to numerically and experimentally design and investigate the accuracy of a magnetic-based off-axis rotational position sensing device intended for the control of a new permanent magnet e-motor, which was developed for a two-wheeler electric vehicle drivetrain. First, a 3D parametric numerical model of a magnetic rotational position sensing device mounted on the motor shaft was built by virtue of the finite element method (FEM). Based on numerical simulations, the appropriate dimensions of the magnetic ring were determined and the possible errors which may have occurred during its manufacturing process have been numerically imposed and analyzed. Second, the rotor position sensing device was prototyped based on the recommendations obtained with the 3D FEM model. Finally, the accuracy of the designed rotational position device was then experimentally assessed by comparing it to a standardized end-of-shaft rotational position encoder. To evaluate the influence of the possible errors on the e-motor rotor position measurement, the output characteristics of the motor torque as a function of its rotational speed of a real permanent magnet e-motor were experimentally assessed using two different rotational position devices. Based on the numerical end experimental results, we identified the manufacturing errors of the magnetic ring and analyzed their influence on the resulting output characteristics of the e-motor. The results revealed that the magnetic ring eccentricity and its magnetization process could affect the accuracy of the e-motor’s output torque characteristics.

• Language: English
• Keywords: electric vehicle motors, electric motor shaft position measurement, e-motor, finite element method FEM, magnetic position sensors, numerical modeling, sensor manufacturing defects
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 22 str.
• Numbering: Vol. 14, issue 4, art. 361
• PID: 20.500.12556/RUL-181158
• UDC: 621.313/.314
• ISSN on article: 2075-1702
• DOI: 10.3390/machines14040361
• COBISS.SI-ID: 273155331
• Publication date in RUL: 26.03.2026

Record is a part of a journal

• Title: Machines
• Shortened title: Machines
• Publisher: MDPI
• ISSN: 2075-1702
• COBISS.SI-ID: 17129750

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: motorji v električnih vozilih, merjenje pozicije rotorja električnih motorjev, metoda končnih elementov MKE, magnetni senzorji pozicije, numerično modeliranje, proizvodne napake senzorjev

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: L2-50084
• Name: Celostno načrtovanje in eksperimentalno modeliranje električnih motorjev

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0258
• Name: Pretvorniki električne energije in regulirani pogoni