TY - GEN
T1 - The effect of asymmetry on torque in permanent magnet motors
AU - Salon, Sheppard
AU - Sivasubramaniam, Kiruba
AU - Ergene, Lale Tukenmez
PY - 2001
Y1 - 2001
N2 - Electronically controlled permanent magnet motors are increasing in popularity due to high efficiency and power density. The noise and vibration issues in permanent magnet motors have not been studied extensively. This paper presents a general purpose method to understand the sources of torque pulsation in permanent magnet motors. This method is based on the analysis of the traveling wave components of the radial and tangential air gap flux. These flux densities are obtained from time domain finite element solutions which are then analyzed to find the time and frequency Fourier components. The harmonic components in the cogging torque can then be attributed to specific air gap flux harmonics. A surface mounted brushless DC motor is used as a case study to analyze the effect of rotor asymmetry on torque pulsation. Several guidelines relating to the finite element modeling of the machine are given concerning grid generation and the inclusion of external circuit connections. The effect of magnet imbalance, static rotor eccentricity, dynamic eccentricity, and combined static and dynamic eccentricity are investigated. Load cases are also studied. These results are then related to the expected frequency components in the torque ripple. The authors conclude the paper with overall comments on the modeling and a discussion of the suitability of these motors for low vibration applications.
AB - Electronically controlled permanent magnet motors are increasing in popularity due to high efficiency and power density. The noise and vibration issues in permanent magnet motors have not been studied extensively. This paper presents a general purpose method to understand the sources of torque pulsation in permanent magnet motors. This method is based on the analysis of the traveling wave components of the radial and tangential air gap flux. These flux densities are obtained from time domain finite element solutions which are then analyzed to find the time and frequency Fourier components. The harmonic components in the cogging torque can then be attributed to specific air gap flux harmonics. A surface mounted brushless DC motor is used as a case study to analyze the effect of rotor asymmetry on torque pulsation. Several guidelines relating to the finite element modeling of the machine are given concerning grid generation and the inclusion of external circuit connections. The effect of magnet imbalance, static rotor eccentricity, dynamic eccentricity, and combined static and dynamic eccentricity are investigated. Load cases are also studied. These results are then related to the expected frequency components in the torque ripple. The authors conclude the paper with overall comments on the modeling and a discussion of the suitability of these motors for low vibration applications.
UR - http://www.scopus.com/inward/record.url?scp=21744448840&partnerID=8YFLogxK
U2 - 10.1109/IEMDC.2001.939301
DO - 10.1109/IEMDC.2001.939301
M3 - Conference contribution
AN - SCOPUS:21744448840
SN - 0780370910
SN - 9780780370913
T3 - IEMDC 2001 - IEEE International Electric Machines and Drives Conference
SP - 208
EP - 217
BT - IEMDC 2001 - IEEE International Electric Machines and Drives Conference
T2 - 2001 IEEE International Electric Machines and Drives Conference, IEMDC 2001
Y2 - 17 June 2001 through 20 June 2001
ER -
