• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.714-716
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• 2003

This paper deals with the characteristic analysis of a brushless DC motor (BLDC) and taking into consideration the freewheeling diodes and DC link voltage ripple using a time-stepped voltage source finite element method. By comparing with the experimental results, we show that the proposed computational method is useful for the analysis and design of a BLDC motor. We also examine the influence of freewheeling diodes and DC link voltage ripples on the performance of a BLDC motor such as torque ripples and radial force on the surface of the teeth.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.955-957
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• 2003

In this paper deal with Initial Pole Position Estimation for Interior Permanent Magnet Motor. Generally, Brushless motor is considered Initial Pole Position with absolute encoder or resolver, etc. In the motor, the flux from the magnets is large enough to saturate the stator iron, results in different inductance values along the pole position. Based upon the relationship between magnitude of inductance and the resultant magnetic filed, initial pole position is estimated at standstill without position sensors, especially, this paper provide the direction of the magnetization. Finally, analysis results are presented to confirm ability of initial pole position estimation.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.744-746
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• 2003

This paper presents characteristics analysis of brushless DC motor(BLDCM) which is driven by four types of PWM mode. The Phase current, radial forte and torque ripples are generated differently at each PWM mode. So they have different influences on motor characteristics. In this paper, we analyzed characteristics of BLDCM using time-stepped voltage source finite element method. The effect of four types of PWM mode had been confirmed by comparing each phase current and torque ripple waveform. The compared simulation result is useful to select a better PWM mode.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1142-1144
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• 2003

This Paper presents a speed controller based on the adaptive fuzzy tuning method for brushless DC(BLDC) motor drives under load variations. Generally, the speed tracking control systems use PI controller due to its simple structure and easy of design. PI controller, however, suffers from the electrical machine parameter variations and disturbances. In order to improve the tracking control performance under load variations, PI controller of which the parameters are modified during operation by adaptive fuzzy tuning method. This method based on optimal fuzzy logic system has simple structure and computational simplicity. It needs only sample data which is obtained by optimal controller off-line. As the sample data implemented in the adaptive fuzzy system can be modified or extended, a flexible control system can be obtained. Simulation results show the usefulness of the proposed controller.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.136-138
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• 2009

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan application. This motor offers advantages of both high-power density and relatively high efficiency This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system. Finally, test results of the prototype motor are provided to verify a validity of the fan application.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.25-29
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• 2001

The BLDCM (Brushless DC Motor) characterized by linear torque to current, and speed to voltage has low acoustic noise, and fast dynamic response. Moreover, it has high power density with high proportion of torque to inertia in spite of small size drive. But, it produce torque ripple due to the motor inductance components in stator windings and back-EMF, when armature current is commutated. Therefore, it is difficult to apply the BLDCM to a precision servo drive system. In this paper is proposed to a new current control algorithm with using fourier series coefficients can minimize torque ripple due to the phase current commutation of BLDCM. Simulation and Experimental results prove the effectiveness the proposed algorithm through comparison with the conventional used unipolar PWM method.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.22-24
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• 2001

This paper presents the characteristics of current harmonics and torque ripple of Brushless DC motor, which is developed the fan blower of vehicles, according to input voltage waveform. To investigate the torque ripple and the phase current harmonics, these characteristics is analysed and compared the experimental results. In the process of analysis, FEM is introduced and computed a transient state torque of BLDC with a sinusoidal and a PWM wave voltage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.48-53
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• 2014

Generally, the usage motor in the vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering starting current of Brushless DC Motor (BLDCM) through Finite Element Method(FEM). As a result, the end of Permanent Magnet (PM) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barrier was limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1013-1014
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• 2007

This paper presents the design of Brushless DC (BLDC) motor using parametric design. According to the variation of magnitude of back emf and inductance, characteristic equations of BLDC motor are solved then output power, current, and torque ripples are calculated. Therefore output characteristics of BLDC motor according to motor parameter can be easily understood, and the range of back emf and inductance satisfying required output performance can be easily found. Presented design method leads to the BLDC motor design to be simple and effective, and the optimal design of BLDC motor using parametric design for 3kW with 50000rpm is presented.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.945-950
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• 2013

This paper deals with the ellipse permanent magnet machines for the minimization of torque ripple based on electromagnetic field theory. On the basis of a magnetic vector potential and a two dimensional (2-D) polar system, analytical solutions for flux density due to permanent magnet (PM) and current are obtained. In particular, the analytical solutions for mathematical expressions of magnets with different circumferential thicknesses can be solved introducing improved magnetization modeling techniques. The analytical results are validated extensively be nonlinear finite element solutions, a reduction of torque ripple can be achieved.