| Title |
Speed Ripple Reduction of Independent Three-phase Permanent Magnet Synchronous Motor considering Unbalanced Back-EMFs |
| Authors |
Chan-Nyeong Heo ; Seon-Hwan Hwang |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2016.30.11.042 |
| Keywords |
IT-PMSM ; Unbalanced Back-EMFs ; Speed Ripple ; PR Controller |
| Abstract |
This paper proposes a speed ripple reduction method of independent three-phase permanent magnet synchronous motor(IT-PMSM) considering unbalanced back-EMFs. The IT-PMSM consists of modular stators and symmetrical rotors with numerous permanent magnets. This structure has some advantages such as maintenance cost reduction, simple manufacturing and transportation. However, the module-based structures cause unbalanced back-EMFs due to non-uniform airgap, which can be happened during manufacturing and installation process. As a result, not only speed and dq axes current ripples but also torque ripple which contain at twice the output frequency appear during operation of the IT-PMSM. These ripple components can be reduced by the proposed PR controller, which reduces specific ripple component. In this paper, the effect of the unbalanced back-EMFs was analyzed by mathematical modeling. In addition, the two times speed and dq-axes current ripple components of synchronous frequency were decreased by the proposed PR controller. The effectiveness of the proposed PR controller was verified through experiments. |