• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.599-601
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• 2001

This paper investigates the permanent magnet (PM) overhang effect on the characteristics such as cogging torque and torque in brushless DC motor (BLDCM). The overhang effect has been used to enlarge the performance of the radial flux density in BLDCM and balance the force in the axial direction for the reduction of the vibration. 3D equivalent magnetic circuit network method (3D EMCNM) is used for the accurate and efficient analysis. The characteristics of BLDCM are analyzed according to the variation of overhang length and the optimal length and ratio of overhang is determined.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.189-190
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• 2016

본 논문은 휠체어의 탑승자의 구동력과 BLDCM(Brushless DC Motor) 에서 출력되는 보조력인 전기적인 구동력을 동시에 사용하는 탈부착형 수전동 휠체어의 제어기를 제안한다. 제안된 방식에서는 탈부착형 수전동 휠체어 제어기는 휠체어의 기울기와 휠체어의 상관관계를 바탕으로, 탑승자의 휠체어 림 구동 상태를 추정하여 휠체어의 전동력을 전달하는 BLDCM에서 구동력을 사용자의 지령에 따라 보조하도록 제어한다. 사용자의 요구 상태는 림의 구동에 따른 휠체어의 상태를 가속도, 자이로 센서를 이용해 측정을 하게 되고, 이를 상보필터를 사용해 각도를 보정하여, 지령치를 계산하고, 구동부는 지령치에 따라 휠체어에 필요한 전동력을 발생하게 된다. 탈부착형 수전동 휠체어의 제어방식은 시뮬레이션을 통해 가능성을 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.325-331
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• 2004

The multiobjective optimization (MO) problem usually includes the conflicting objectives and the use of conventional optimization algorithms for MO problem does not so good approach to obtain an effective optimal solution. In this paper, genetic algorithm (GA) as an effective method is used to solve such MO problem of brushless DC motor (BLDCM). 3D equivalent magnetic circuit network (EMCN) method which enables us to reduce the computational burden is also used to consider the 3D structure of BLDCM. In order to effectively obtain a set of Pareto optimal solutions in MO problem, ranking method proposed by Fonseca is applied. The objective functions are decrease of cogging torque and increase of torque respectively. The airgap length, teeth width and magnetization angle of PM are selected for the design variables. The experimental results are also shown to confirm the validity of the optimization results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.50-52
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• 2003

This paper presents characteristics analysis of brushless DC motor(BLDCM) which driven by two types of PWM mode. The phase current and torque ripples are generated differently at each PWM mode. So they have a different influence on motor characteristics. In this paper, we have analyzed characteristics of BLDCM using time-stepped voltage source finite element method. The effect of two 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.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.449-454
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• 2005

Brushless DC Motor(PM BLDCM) is widely used in industrial applications due to its high efficiency and power density. In order to increase reliability and reduce system cost, this paper studies particularly applicable method for sensorless PM BLDCM drive system. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition, and is practically free of noise that can be introduced by the inverter switching, making this a robust sensing method. As a result, the method described here is not sensitive to filtering delays, allowing the motor to achieve a good performance over a wide speed range. In addition, a simple starting method and a speed estimation approach are also proposed.

• 전력전자학회논문지
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• 제20권2호
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• pp.193-199
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• 2015

This paper proposes a regeneration braking algorithm for Brushless DC (BLDC) motor system. The unipolar switching method has a limitation about the regeneration braking when the BLDC motor is operated in the low speed region. The proposed algorithm alternatively utilizes the unipolar and bipolar switching method to implement the regeneration braking for overall speed range. The bipolar switching method is used when the BLDC motor is operated in the low speed region. The switching transition point is determined by analyzing the unipolar and bipolar switching during the regeneration braking. The effectiveness of proposed algorithm is verified by using the experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.660-664
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• 2004

The indirect rotor position detection method using terminal voltage of brushless DC motor (BLDCM) requires simple control circuit, and has wide speed range of sensorless operation. However, because the substantial phase difference exists between real back emf and terminal voltage, the existing indirect detection method using analog filter which is affected by frequency, speed, and load sensitively cannot be synchronized with current, in the end, it advances or delays. This paper presents new analog filter circuit design for rotor position estimation in order to solve the problem, and proposes novel sensorless operation method which is stable even in high speed range and not influenced by parameters with analysis on phase difference by load and speed. Moreover, the appropriateness of the proposed sensorless drive in this paper is verified and analyzed by experimentation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.790-791
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• 2008

이 연구는 이동 매쉬기법이 고려된 유한요소 해석법을 이용한 영구자석 Brushless 직류모터(BLDCM)의 동적 특성해석을 다루었다. 이 논문의 초점은 BLDCM의 적합한 속도 제어를 위한 정현파 구동시스템의 적합성을 보여주고 있다. 각각의 구형파 시스템과 BLDC 구동시스템의 제안된 속도리플과 전류응답을 비교하였다. 실험결과들에 의해 속도제어 시스템은 해석되어졌고, 정현파 구동시스템의 유효성은 검증되었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.129-132
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• 2002

The first purpose of this paper is to develop the sensorless drive at adjustable speed without any mechanical position or speed sensor. For this, this research analyzes terminal voltage, finds the rotor position information and makes the source of commutations of phase current. The second purpose is to propose the sensing method of initial rotor position without instantaneous rotating. Experimental results show the validity and practical use of the proposed sensing method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권1호
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• pp.23-29
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• 2001

A BLDC motor has a serious drawback that torque pulsation is generated in every commutation period though it has many advatages compared to the conventional DC Motor. In this paper, the influence of commutation time on torque pulsation is studied. Generally in calculating the torque of BLDC motor, it is assumed that the decaying phase back EMF is constant, but the torque model considering decaying phase back EMF is introduced here. Through it, the torque in commutation period has torque pulsation component caused by commutation itself and it cannot be removed perfectly even if there is no current pulsation. To reduce the torque pulsation, a new method is proposed, which controls a point of commutation and the optimal point of commutation is found. Simulation shows that proposed method reduces the torque pulsation considerately.