TY - GEN
T1 - Direct torque control of four-switch brushless DC motor with non-sinusoidal back-EMF
AU - Ozturk, Salih Baris
AU - Alexander, William C.
AU - Toliyat, Hamid A.
PY - 2008
Y1 - 2008
N2 - This paper presents a direct torque control (DTC) technique for brushless dc (BLDC) motors with non-sinusoidal back-EMF using 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 PWM current and voltage control schemes, by properly selecting the inverter voltage space vectors of the two-phase conduction mode 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 PWM current and especially voltage control schemes. In addition, for effective torque control in two phase conduction mode, a novel switching pattern incorporating with the voltage vector look-up table is designed and implemented for four-switch inverter to produce the desired torque characteristics. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, pre-stored back-EMF constant versus position lookup 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 using four-switch inverter with faster torque response due to the fact that the voltage space vectors are directly controlled. Therefore, the direct torque controlled four-switch three-phase BLDC motor drive could be a good alternative to the conventional six-switch counterpart with respect to low cost and high performance. A theoretical concept is developed and the validity and effectiveness of the proposed two phase conduction four-switch DTC scheme are verified through the simulations and experimental results.
AB - This paper presents a direct torque control (DTC) technique for brushless dc (BLDC) motors with non-sinusoidal back-EMF using 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 PWM current and voltage control schemes, by properly selecting the inverter voltage space vectors of the two-phase conduction mode 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 PWM current and especially voltage control schemes. In addition, for effective torque control in two phase conduction mode, a novel switching pattern incorporating with the voltage vector look-up table is designed and implemented for four-switch inverter to produce the desired torque characteristics. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, pre-stored back-EMF constant versus position lookup 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 using four-switch inverter with faster torque response due to the fact that the voltage space vectors are directly controlled. Therefore, the direct torque controlled four-switch three-phase BLDC motor drive could be a good alternative to the conventional six-switch counterpart with respect to low cost and high performance. A theoretical concept is developed and the validity and effectiveness of the proposed two phase conduction four-switch DTC scheme are verified through the simulations and experimental results.
UR - http://www.scopus.com/inward/record.url?scp=52349107085&partnerID=8YFLogxK
U2 - 10.1109/PESC.2008.4592717
DO - 10.1109/PESC.2008.4592717
M3 - Conference contribution
AN - SCOPUS:52349107085
SN - 9781424416684
T3 - PESC Record - IEEE Annual Power Electronics Specialists Conference
SP - 4730
EP - 4736
BT - PESC '08 - 39th IEEE Annual Power Electronics Specialists Conference - Proceedings
T2 - PESC '08 - 39th IEEE Annual Power Electronics Specialists Conference
Y2 - 15 June 2008 through 19 June 2008
ER -