AUTHOR : Young-Sung Kim, Doo-Young Kim, Hyeon-Jin Park, Jung-Pyo Hong
ORGANIZATION : KSAE
JOURNAL :
YEAR : 2015
VOL :
ISSUE : EVS 28
PAGE : 1 ~ 6
An analysis to find the cause of noise and vibration of a 4 pole 44/48 (rotor/stator) slot induction motor for Electric Vehicle (EV) when accelerating was performed. A noise problem appeared when accelerating. To define the source of this problem, tests under different acceleration situations have been carried out. There were three acceleration conditions with increasing accelerations. The noise inside the EV and vibration of the motor mounted in the car were measured. With increasing acceleration, the amplitudes of 22nd, 24th, and 46th harmonic increased. These harmonics are created by normal force harmonics that are created by interaction of flux density harmonics. The harmonics that create these harmonics are found through analytic method. Analysis of these harmonics shows that these harmonics are created by rotor slot harmonics. Higher current input is needed to achieve higher torque, and higher torque means higher acceleration. This causes saturation in the tooth tips of the motor, which increases the influence of rotor slots harmonics. Applying skew to the rotor is chosen as the solution to reduce noise and vibration of the target motor. The current waveform when skew is applied is analytically created and compared with unskewed current waveform since harmonics in the current waveform is proportional to flux density harmonics. Normal force before and after skewing the rotor was compared. Harmonic analyses showed that amplitude of harmonic orders noted forehand through testing decreased in current and normal force waveforms. In conclusion, this paper proposes an analysis method using harmonic analysis for finding source of noise and vibration of a motor.