• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2203-2205
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• 2003

In this thesis, it is a purpose to carry out speed control of DC servo motor without using encoder and the resolver which are speed sensor of DC servo motor and it should use estimate algorithm or observer and must assume a speed in order to control speed sensorless. Therefore, high gain observer was designed to estimate rotor speed of DC servo motor and it carries out speed control from the feedback of the speed that assumed done in the thesis. Also, implementation used easy PI controller in speed-controller of DC motor though it was simple. It is compared estimate performance of Luenberger and high gain observer in a way of computer simulation in order to verify performance of the high gain observer which proposed in this thesis, and proved excellency of the high gain observer. And the thesis proved that smooth speed sensorless control of DC servo motor was implemented in invariable driving.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.184-188
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• 1999

Switched Reluctance Motor has doubly salient poles in stator and rotor, windings are wound in just stator and no magnet or windings on the rotor. This configuration is robust mechanically and thermally. The inverter of SRM is more robust than that of induction or brushless DC(BLDC) motor, but still its drive is comparatively expensive for home appliance. To drive the conventional three or four-phase SRM, 6 to 8 power switches are required when asymmetric bridge inverter is employed. Generally, more than 50% of the cost for the SRM drive is allocated to power devices and gate drives. This paper proposed single phase SRM that have both radial and axial air gaps. The stator and rotor were stacked with two types of stampings that have different diameters. This configuration is very effective to increase align inductance(Lmax). The high value of Lmax increases the motor efficiency and power density. The proposed single phase SRM(Claw SRM) can be driven by only two power switches. To show the validity of the proposed idea, the analysis using finite element method(FEM) and experimental works are carried out. The proposed SPSRM can be driven with high efficiency and can be made compactly and inexpensively because of high value of align inductance and less number of switches. For the comparison, we used same stator for three-phase and single phase, and slightly different stator and rotor for proposed single phase SRM(Claw SRM)

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권7호
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• pp.346-352
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• 2006

In Brushless DC Motor, there are Permanent Magnets (PMs) with driving circuit and sensor for detecting to rotor position and rotation speed. In the case of using hall IC sensor which response to magnetic flux, that is required to additional sensor magnet for rotor position detecting. Most of BLDC motor, However, take asymmetrical overhang of PM in rotor instead of additional sensor magnet for operating of hall IC sensor. The asymmetrical overhang of PM occur rotor thrust to z-axis direction that is lead to not only damage of bearing but also intensive noise and vibration. Therefore, the analysis of magnet overhang effect in the side of vibration and drive to hall If sensor is required to precise. In this paper, 2-D Finite Element Method is used to solve precise field computation and thrust of z-axis direction considering asymmetrical magnet overhang. And also the z-axis thrust from the analysis result is compared to experimental result. In conclusion, the purpose of this paper minimize to noise and vibration of BLDC Motor as analyzes to asymmetrical magnet overhang effect.

• Journal of Magnetics
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• 제21권2호
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• pp.173-178
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• 2016

Six-step commutation control widely used in brushless DC (BLDC) motor can be applied to consequent pole permanent magnet (CPPM) belt starter generator (BSG) with trapezoidal back electromotive force (EMF) in the starter state. However, rotor position detection with three Hall sensors in BLDC motor can hardly be employed in CPPM BSG due to asymmetric flux distribution in each pole side of CPPM BSG. This paper presents a low-cost rotor position detection method for CPPM BSG in which six Hall sensors are proposed to be used based on the analysis of flux distribution by 3D FEA. In the method, the six Hall sensors are divided into three groups and two signals in each group are combined through performing logic operations. In addition, offset angle between back EMF and the related Hall signal can be compensated by moving the Hall sensors. Experiments of a 2 kW CPPM BSG prototype have also been performed to verify the proposed method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권6호
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• pp.325-336
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• 2006

This paper deals with the dynamic analysis of variable speed wind power systems with doubly-fed induction generators (DFIG). First, the mathematical modeling of wind farm which consists of turbine rotor, DFIG, rotor side and grid side converter and control systems is presented. In particular, the equation for dynamic modeling of the DFIG and the AC/DC/AC converter is expressed as dq reference frame. And then, on the basis of mathematical modeling for each component of wind farm, dynamic simulation algorithms for speed and pitch angle control of wind turbine and generated active and reactive power control of the DFIG and the AC/DC/AC converter are established. Finally, Using the MATLAB/SIMULINK, this paper presents dynamic simulation model for 6MW wind power generation systems with the DFIG considering distribution systems and performs the dynamic analysis of wind power systems in steady state. Moreover, this paper also presents the dynamic performance for the case when the voltage sag in grid source and phase fault in bus are occurred.

• 조명전기설비학회논문지
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• 제20권10호
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• pp.74-81
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• 2006

본 논문은 회전자 위치와 속도 정보를 가진 고정자 자속을 추정할 수 있는 프로그래머블 저역통과 필터를 이용한 비돌극 영구자석형 동기전동기의 센서리스 벡터제어를 제안한다. PLPF를 사용한 PMSM의 센서리스 벡터제어는 LPF와 순수적분기가 갖는 DC 드리프트 문제를 해결할 수 있다. 또한 PLPF는 정확한 회전자 위치와 속도 추정을 위해 위상과 이득 보상기를 갖는다. 그러므로, 드리프트와 옵셋 문제는 PLPF로써 해결되기 때문에 위치 및 속도의 정보는 정확히 추정된다. 실험결과는 정격속도의 10[%]이상과 부하상태에서 좋은 성능을 보여준다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권9호
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• pp.476-483
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• 1999

In this paper, electromagnetic forces acting on the rotor surface of a BLDC motor for hard disk drive are calculated by the finite element field analysis. The frequency characteristics of torque ripple, local force and unbalanced magnetic force as a source of mechanical vibration area analyzed. Ring-type permanent magnets for the brushless DC motor are apt to have different magnetization levels at each pole because of the unbalanced air gap between the magnet surface and the magnetizer fixture during the multi-poles magnetizing process. This paper discusses the effect of the unsymmetric magnetization distribution in the permanent magnet on the brushless DC motor performances. As a result, the unbalanced magnetic force acting on the rotor surface and the torque ripple are examined for the motor with an unsymmetric magnetization distribution, and compared with those of an ideally symmetric motor.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.370-376
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• 2009

The influence of magnetic saturation on electromagnetic field distribution in both a permanent-magnet direct-current (PMDC) motor and a field-winding (wound-field) direct-current (FWDC) motor, with the same output mechanical power, has been studied. In this paper, an approximate analytical method and time-stepping Finite Element Method (FEM) are used for prediction of Back-EMF and electromagnetic torque. No-load and rotor-lucked conditions, according to experimental measurements, and the FEM and analytical method studies of the motors have been considered. A sensitivity analysis has also been successfully accomplished on the major design parameters that affect motor performance. At last, these two DC motors are compared, in spite of their differences, on the basis of measured output characteristics.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.591-595
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• 2000

In this paper we proposed a new sensorless drive system for the trapezoidal type brushless DC motor which does not use any mechanical position or speed sensor and applicable to the systems requiring a constant speed and torque such as Fan. For this a novel indirect rotor position sensing technique based on a detailed analysis of the terminal voltage characteristics is proposed in this paper. And a sensorless drive system for the brushless DC motor is implemented using a 87c196mc fo the main microprocessor and a power FET for the inverter. The experimental results will show the validity of the proposed indirect sensing method and the practical use of the sensorless drive

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.66-68
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• 2005

DC motor is easy to control and can make torque easily. DC motor uses wide range. But DCmotor have limited by using a brush and structural complexity. But, BLDC doesn't have brush so that is more simple than DC motor, and the rotor of BLDC motor is made by permanent magnet that dose not need to make a fixed flux speed for flux current. BLDC motor is very efficiency, controllable, and reliable. This paper presents an error detection with a BLDC motor current. Generally, BLDC motor current is used to current feedback, so that can make a critical fault in the system. this paper suggests to detect error by inspection of threshold current value both positive and negative.