• 한국정보통신학회논문지
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• 제15권5호
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• pp.1018-1024
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• 2011

최대 토크를 발휘하도록 정현파형 영구자석형 동기전동기를 구동하기 위해서는 회전자 절대위치에 동기화된 120도 위상차를 갖는 3상 정현파 전류 입력이 고정자 코일에 요구된다. 그러므로 회전자 절대위치 검출이 필연적이다. 그리고 고정자 자계와 회전자 자계 사이의 90도 위상 관계가 정류 동작에 의해 유지되어야 한다. 정류를 위한 절대 위치 검출은 일반적으로 모터 축에 부착된 엔코더 출력 신호의 분석에 의해 이루어진다. 본 연구는 현대의 엔코더 시스템을 부착한 모터의 절대위치를 검출 할 수 있는 신호처리 논리회로 설계를 목적으로 하며, 고정자 코일에 정현파 전류 입력을 만들어주기 위한 삼상 기준파형을 발생시킨다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2365-2372
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• 2011

BLDC 모터와 같은 동기전동기에서 소음과 진동의 원인이 되는 코깅토크는 전동기내의 비 균일 토크로서 전동기 시스템의 자기 에너지가 최소인 위치로 이동하려는 접선방향의 힘으로 부하전류와 상관없이 회전자 영구자석과 고정자 슬롯의 상호작용에 의해 발생한다. 이러한 코깅토크는 전동기의 소음과 진동의 주요 원인이 되므로 전동기 설계 시 반드시 고려해야 한다. 코깅토크는 영구자석이 부착된 회전자에 의하여 공극 중에 비교적 저차의 고조파 자속밀도와 고정자 철심 슬롯의 상호작용으로 발생한다는 점을 중시하여 본 논문에서는 실험계획법의 일종인 반응표면 법을 사용하여 코깅토크를 저감하는 방법에 대해 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.139-141
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• 1996

The switched reluctance motors(SRM) are simple and robust in structure. Because the wide range of power and speed, their application field is increasing. In order to design the motors and to evaluate the performance of them properly, an accurate study about the analysis of motor characteristics is required. In this paper, for the analysis of SRM characteristics, the finite element method which is based on the solution of combined equations both the electromagnetic field equations and the circuit equations of stator is adopted. The analysis model is to he assumed two-dimensional and the nonlinear property of magnetic materials is considered by Newton-Raphson method. To verify the usefulness of the proposed algorithm, commercial SRM is chosen and simulated. The computed torques obtained by Maxwell Stress Tensor are compared with the experimental data and it is found that they are in good agreement. By applying the proposed algorithm to two cases, currents of stator and torques at every angular positions of rotor are obtained step by step. Comparing them, one can recognize that torque ripple of SRM can he improved by controlling the switching sequences of driving circuits.

• 전력전자학회논문지
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• 제11권3호
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• pp.284-291
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• 2006

최근 가전 및 자동차시스템의 전동화에 따라 고효율 전동기에 대한 관심이 고조되고 있다. 따라서 본 논문에서는 고속구동시 고효율구동이 가능한 코어없는 AFPM전동기의 운전특성에 대해서 기술하고 설계관점에서의 그 전기적 특징에 대해서 논의한다. 특히 전동기 특성에 큰 영향을 미치는 역기전력 및 공극에서의 자계특성을 보이고 또한 인덕턴스특성에 따른 제어특성에 대해서도 시뮬레이션 및 실험을 통해 고찰한다. 회로망법을 기초로한 전동기설계결과와 출력특성실험결과의 비교검토를 통해 토크-속도 및 효율운전특성을 확인하였으며 제어특성을 확인한다. 아울러 코어가 없어짐에 따라 생길 수 있는 진동 및 소음특성에 대해서도 평가한다.

• 한국유체기계학회 논문집
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• 제19권6호
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• pp.55-60
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• 2016

We present an experimental setup for measuring the mechanical performance of centrifugal blood pumps. Using a 3D printer to construct supporting parts and magnetic couplings, we developed the measurement setup that can be used for various types of blood pumps. The experimental setup is equipped with sensors to measure a variety of mechanical characteristics of blood pumps including pressure, flow rate, torque, temperature, and rotating speed. Our experimental measurements for two commercial blood pumps are consistent with data provided by manufacturers, which indicates that the our setup offers the accurate measurements of blood pump performance. Utilizing the experimental setup, we tested aqueous glycerin solutions mimicking the density and viscosity of blood, which enabled us to predict the difference in operations using water and blood.

• Journal of Advanced Marine Engineering and Technology
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• 제31권2호
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• pp.138-144
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• 2007

The variation of the crankshaft speed in a multi-cylinder engine is determined by the resultant gas pressure torque and the torsional deformation of the crankshaft. Under steady state operation, the crankshaft speed has a quasi-periodic variation. For the diagnosis the engine instantaneous speed versus crankshaft angle is utilized. This paper describes a simple measurement method of the engine instantaneous speed versus crankshaft angle using the teeth on the flywheel of the crankshaft. Two non-contacting magnetic pickup combinations detect the crank angle and TDC position for the data acquisition. The results from experiments on a 6 cylinder marine diesel engine demonstrate that the crankshaft speed variation are detected with good resolution. And the crankshaft speed variation is investigated according to the operation conditions. Also, it is confirmed that the engine output measured by EMS can be evaluated larger than the actual value due to TDC position error caused by instantaneous speed variation.

• 한국산학기술학회논문지
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• 제11권10호
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• pp.3633-3640
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• 2010

헬리컬형으로 자화된 영구자석을 이용한 비접촉 마그넷 기어를 개발하기 위하여 3차원 FEM 해석 기법을 활용하였고 마그넷 기어의 자기적 특성 해석 및 설계 요소기술을 확보하였다. 마그넷 기어를 이용한 클린 반송 컨베이어 및 회전장치의 성능평가를 위하여 class 10의 클린부스 환경에서 시험운전을 거쳐, 이송 속도, 최대 허용 토크, 클린도, 최대 이송 중량, 헌팅 유무, 소음도 등을 측정한 결과 클린도 class 10의 공정까지도 대응이 가능한 것으로 확인되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.170-172
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• 2003

Among low power servo applications, classical DC motors are very popular because they are reasonably cheap and easy to control. The main disadvantage is the mechanical collector which has only a limited life period. Also, brush sparking can destroy the rotor coil, generate EMC problems. So permanent magnet brushless do motors and drives are being used increasingly in a wide range of applications. This has been made possible with the advantages of high performance permanent magnets with high coercively and residual magnetic, which make it possible for the PM to have superior power density, torque to inertia ratio and efficiency, when compared to an induction or conventional dc machine. This paper presents the design of a PM brushless dc motor drive simplistically operates as a classical dc motor. The BLDC motor drive system for this paper composes to the power integrated circuits, the one chip device. And several simple semiconductors add to drive system for a motor drive system simplistically operates as a conventional dc motor. Test results confirmed the feasibility of the proposed motor drive system design.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.135-142
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• 2016

Generally, closed slots are adopted to reduce the water friction loss in both the stator and the rotor of water filling submersible motor due to the special environment of operation. One of the obvious differences between the traditional induction motors and water filling submersible motors is that the submersible motors only need relatively smaller starting torque. This paper aims to analyze the slot leakage reactance of water filling submersible motor during starting transient operation. An improved analytical method which considered the magnetic saturation of the slot bridge and the skin effect of rotor bars is proposed. The slot permeance factor which has a direct impact on the slot leakage reactance is calculated. Then finite element models with different stator slot types are constructed and search coils are introduced to measure the slot flux linkage. Moreover, the starting performances of the models with two typical stator slots are compared and the flux leakage characteristics are obtained. Finally, the results obtained by finite element method are very close to the results obtained by analytical method.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1842-1850
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• 2017

Reducing the noise and vibration of the BLDC motors is very essential for some special applications. In this paper, a new structural design is introduced to increase the natural frequencies of the stator in BLDC motors as increasing the natural frequencies can reduce the severe effects of the structural resonances, including high levels of noise and vibration. The design is based on placing a single hole on definite regions at the stator cross sectional area (each region contains one tooth and its upper parts in the stator yoke) in an optimum way by which the natural frequencies at different modes are shifted to the higher values. The optimum diameter and locations for the holes are extracted by the Response Surface Methodology (RSM) and the modal analyses in the iterative process are done by Finite Element Method (FEM). Moreover, the motor performance by the optimum stator structure is analyzed by FEM and compared with the prototype motor. Preventing the stator magnetic saturation and the motor cogging torque enhancement are the two constraints of the optimization problem. The optimal structural design method is applied experimentally and the validity of the design method is confirmed by the simulated and experimental results.