Direct Torque Control of Four-Switch Brushless DC Motor With Non-Sinusoidal Back EMF


Ozturk S. B. , Alexander W. C. , Toliyat H. A.

IEEE TRANSACTIONS ON POWER ELECTRONICS, cilt.25, ss.263-271, 2010 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 25 Konu: 2
  • Basım Tarihi: 2010
  • Doi Numarası: 10.1109/tpel.2009.2028888
  • Dergi Adı: IEEE TRANSACTIONS ON POWER ELECTRONICS
  • Sayfa Sayıları: ss.263-271

Özet

This paper presents a direct torque control (DTC) technique for brushless dc (BLDC) motors with non-sinusoidal back electromotive force (EMF) using a four-switch inverter in the constant torque region. This approach introduces a two-phase conduction mode as opposed to the conventional three-phase DTC drives. Unlike conventional six-step current and voltage control schemes, by properly selecting the inverter voltage space vectors from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained. Therefore, a much faster torque response is achieved compared to conventional current and voltage control schemes. In addition, for effective torque control, a novel switching pattern incorporating the voltage vector look-up table is designed and implemented for a four-switch inverter to produce the desired torque characteristics. Furthermore, to eliminate the low-frequency torque oscillations, pre-stored back EMF constant versus position look-up tables are designed and used in the torque estimation. As a result, it is possible to achieve two-phase conduction DTC of a BLDC motor drive with faster torque response due to the fact that the voltage space vectors are directly controlled. A theoretical concept is developed and the validity and effectiveness of the proposed DTC scheme are verified through the simulations and experimental results.