A new topology for unipolar brushless DC motor drive with high power factor Academic Article uri icon


  • A new converter topology is proposed for driving a permanent magnet brushless de (BLDC) motor with unipolar currents. It is based on a front-end single-ended primary inductance converter (SEPIC) and a switch in series with each phase. All the switches are ground-referenced, which simplifies their gate drives. The available input voltage can be boosted for better current regulation, which is an advantage for low voltage applications. For operation with an ac supply, the SEPIC converter is designed to operate in the discontinuous conduction mode. In this operation mode, it approximates a voltage follower and the line current follows the line voltage waveform to a certain extent. The reduction in low-order harmonics and improved power factor is achieved without the use of any voltage or current sensors. The simplicity and reduced parts count of the proposed topology make it an attractive low-cost choice for many variable speed drive applications.

published proceedings


author list (cited authors)

  • Gopalarathnam, T., & Toliyat, H. A.

citation count

  • 70

complete list of authors

  • Gopalarathnam, T||Toliyat, HA

publication date

  • November 2003