• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1204-1206
• /
• 2005

This paper deals with magnetic field analysis and computation of cogging torque in IPM motor with an analytical method, which is based on the Conformal Mapping technique. The magnetic field is analyzed by solving space harmonic field analysis due to inserted PM magnetizing distribution. Conformal Mapping method is then used for considering the slot opening effect and rotor saliency effect on the air-gap field magnetic distribution. Then, by integrating the field over the stator surface, cogging torque is calculated. The validity of the proposed analytical method is confirmed by comparing the results with 2-D FEA results.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.67-69
• /
• 1998

The cogging torque in the small BLDC motors used in the DVD driving system or HDD driving system can cause some serious vibration problem. In this paper, some core shapes that reduce cogging torque are found by using reluctance network method(RNM) for magnetic field analysis and genetic algorithm(GA) for optimization. The outer rotor type BLDC motor for the DVD ROM driving system has been optimized as an sample model.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.158-160
• /
• 2006

The structure of interior permanent magnet type brushless DC motor (IPM type BLDC motor) has high saliency ratios that produce additional reluctance torque. But this structure has a significant cogging torque that may cause acoustic noise and vibration. In this paper describes an optimization of flux barrier in order to reduce cogging torque and torque ripple in IPM type BLDC motor using the Taguchi methods. The optimal design consider- ed noises such as manufacturing tolerances of permanent magnet size. So, optimal design ensures that torque performance is insensitive to noise.

• Journal of Magnetics
• /
• v.19 no.4
• /
• pp.411-417
• /
• 2014

This paper presents the shape optimization of a permanent magnet synchronous motor to reduce the torque ripple and iron loss. Specifically, the harmonics of the electromotive force and cogging torque are decreased by adjusting the permanent magnet arrangement and non-uniform air gap length. In addition, an additional flux path along the q-axis is proposed with a unique rotor shape to increase the q-axis inductance and reluctance torque. The improvement in the performance of the proposed model is verified with simulated and experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.291-294
• /
• 2004

Many researches have been focused on optimal designs of a pole shape in order to reduce cogging torques, which are generated between permanent magnets and slots. In this paper, an adaptive controller is proposed for reducing the effect of cogging torques in servo motors. The controller stabilizes the control system and shows an excellent trajectory tracking performance compared to the conventional PD controller.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.6 s.171
• /
• pp.70-75
• /
• 2005

Many researches have been focused on optimal designs of a pole shape in order to reduce cogging torques, which are generated between permanent magnets and slots. In this paper, an adaptive controller is proposed fur reducing the effect of cogging torques in servo motors. The controller stabilizes the control system and shows an excellent trajectory tracking performance compared to the conventional PD controller.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.2
• /
• pp.112-118
• /
• 2004

Recently, development of rare earth permanent magnet with the high remanence, high coercivity allows the design of brushless motors with very high efficiency over a wide speed range. Cogging torque is produced in a permanent magnet by magnetic attraction between the rotor mounted permanent magnet and the stator teeth. It is an undesired effect that contributes to output ripple, vibration, and noise of machine. This cogging torque can be reduced by variation of magnet arc length, airgap length, magnet thickness, shifting the magnetic pole and varying the radial shoe depth and etc. In this paper, some airgap length and magnet arc that reduce cogging torque are found by finite element method(FEM) and Maxwell stress tensor method. The SPM(Surface Permanent Magnet) type of high-power Brushless DC (BLDC) motor is optimized as a sample model.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.4
• /
• pp.390-393
• /
• 2013

In this paper, we proposed how the V-skew applied of the rotor to inprove the characteristics of cogging torque in large PMSM. Large PMSM is difficult to apply a pitch of the diagonal magnetic skew because of the motor's structure and making. In addition, the force in the direction of z-axis occurs when the diagonal skew is applied. So we are applying the optimal v-skew to reduce torque ripple and cogging torque because this reduces the noise and vivration on the motor. Throug FEM dD analysis, we studied to find the optimal v-skew angle for reducing torque ripple.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.891_892
• /
• 2009

This paper presents the rotor study on the deal with the shape design with a flux barrier to minimize the cogging torque of Interior Permanent Magnet Synchronous Motor(IPMSM). In order to consider the notch effect, the torque characteristics according to the shape of notch is performed and analyzed. From the this results, we found that an optimal location and radius of the notch effectively suppresses the torque pulsation of the IPM drive. The rotor shape design also shows improvement in the average torque

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.1
• /
• pp.64-69
• /
• 2012

In this paper, the optimal design of notch and barrier was carried out in order to improve characteristics of constant torque with minimizing the cogging torque occurred by teeth and slot structure. Optimized design was carried out by design of experiment and various characteristics including torque were studied by finite element method(FEM). In addition, in order to verify resonance frequency, natural frequency of the stator was analyzed by modal analysis.