• 전력전자학회논문지
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• 제21권2호
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• pp.134-143
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• 2016

This paper proposes a novel asymmetrical interior permanent magnet (IPM) brushless DC (BLDC) motor structure, which utilizes half-type permanent magnet (PM) configuration and has asymmetrical side gaps (slot next to the PMs) for reducing torque ripples. This structure uses 24% less volume of PMs than conventional IPM BLDC motor with a full set of magnets. The characteristics of the proposed motor are compared with three other half-type IPM BLDC motors through finite elements method (FEM) analysis, and the usefulness of the proposed motor was verified through experimental evaluation on prototypes of the conventional motor and proposed motor under various torque load conditions. This research obtained a high-performance IPM BLDC motor while decreasing manufacturing cost at the same time.

• 전기학회논문지
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• 제61권11호
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• pp.1611-1616
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• 2012

Recently, the stationary discontinuous armature Permanent Magnet Linear Synchronous Motor(PM-LSM) was suggested as a driving source for long-distance transportation system. However, as these motors arrange armatures discontinuously, there occurs an edge which causes the cogging force. This works as a factor that bothers acceleration and deceleration that takes place when movers enter into and eject from the armatures. Therefore, installation of auxiliary teeth on the edge of armature of PM-LSM is suggested in order to reduce cogging force caused by the edge when the armature is placed in a discontinuous arrangement. But length of auxiliary teeth can be changed if install it with auxiliary pole in order to decrease more and more edge cogging force. On this, in the study, decided on a design variable of auxiliary teeth and used 2-D FEA, and examined edge cogging force characteristic along this in order to grasp length of auxiliary teeth changed according to installation positions of an auxiliary pole.

• 전기학회논문지
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• 제62권12호
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• pp.1661-1667
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• 2013

This paper studies the dynamic irreversible demagnetization characteristics of an interior permanent magnet (PM) brushless DC motor with a stator turn fault. A new algorithm, which is a finite element method (FEM) combined with a line voltage equation of the motor, is developed to analyze irreversible demagnetization under dynamic and transient states and considers a stator turn fault. The input current, circulating current, magnetic distribution characteristics, and operating property of the PM, including the irreversible demagnetization in the fault state, are analyzed using this algorithm by considering the magnetic saturation effect. The feasibility of the proposed method confirmed from the analysis results is verified via an experiment. Through this fault analysis, we can accurately check the fault phenomena of a PM motor against the demagnetization fault for fault prevention.

• Journal of Power Electronics
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• 제17권5호
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• pp.1223-1230
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• 2017

The back emf harmonics of a permanent magnet (PM) synchronous motor is a major source of torque ripple. For torque control applications including column fitted MDPS (motor driven power steering) systems, it is essential to reduce the mechanical vibrations due to torque ripples at low speeds. In this paper, a torque ripple reduction algorithm for interior PM synchronous motors is proposed. The harmonic currents that cancel the $6^{th}$ order torque harmonic are added to the nominal dq currents for MTPA (maximum torque per ampere) operation. The compensated harmonic currents are derived from flux linkage harmonics based on a FFT analysis of the back emf harmonics. Simulation and experimental results verify that the $6^{th}$ order torque harmonic and THD of the torque ripple are reduced by compensating the dq harmonic currents.

• Journal of Magnetics
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• 제18권3호
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• pp.352-356
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• 2013

Recently, the stationary discontinuous armature, Permanent Magnet Linear Synchronous Motor (PM-LSM), was suggested as a driving source for long-distance transportation system. However, as these motors arrange armatures discontinuously, an edge occurs thereby leading to a cogging force. This works as a factor that hinders the acceleration and deceleration that takes place when movers enter into and eject from armatures. Therefore, in this study, the installation of auxiliary teeth on the edge of the armature of PM-LSM is suggested in order to reduce the cogging force caused by the edge when the armature is placed in a discontinuous arrangement. Auxiliary teeth are optimally designed by a 2-D numerical analysis using the finite element method was performed to generate the optimum design of the auxiliary teeth. The validity of the study was confirmed through the comparison of the cogging force induced at the edge in respect to the design parameter using the basic model.

• 대한기계학회논문집A
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• 제41권6호
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• pp.525-532
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• 2017

차세대 주력 디스플레이인 유기 및 양자점 발광 다이오드를 잉크젯을 이용하여 저렴한 비용으로 생산하기 위한 연구개발이 진행되어 왔으며, 잉크 액적의 토출 신뢰성을 고속으로 검사하기 위한 모니터링 장비의 개발이 요구된다. 본 연구에서는 기존 직선 운동 방식의 잉크젯 모니터링 장비 대신에 로터리 및 리니어 초음파 모터를 이용하여 미러를 회전시킴으로써 노즐들에서 토출되는 잉크 액적들을 모니터링할 수 있는 장비를 개발하여 측정 능력을 시험하였다. $10{\mu}m$, $30{\mu}m$ 및 $50{\mu}m$ 직경 원형의 측정 오차는 각각 $0.5{\pm}1.0{\mu}m$, $-1.2{\pm}0.3{\mu}m$ 및 $0.2{\pm}0.5{\mu}m$였다. 모니터링 시간은 17초가 소요되었으며, 제어 프로그램의 최적화를 통해 8.6초까지 모니터링 시간을 단축할 수 있는 가능성을 확인하였다.

• 대한기계학회논문집B
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• 제38권3호
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• pp.243-254
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• 2014

고속 저토크 표면 부착 영구자석형 동기 전동기의 운전 안정성 확보를 위하여 과속도 및 과부하 영역에서 전동기 코일 온도 예측이 필수적이다. 0.35mm 의 S18, S08 등급인 35PN440, 35PN220 그리고 0.15mm 의 저손실 재료인 15HTH1000 으로 제작된 고정자 철심을 포함하는 전동기의 정격 구동 조건에서 손실 및 코일 온도를 측정하여 과속도 및 과부하 영역의 손실 및 열저항을 예측하고 열전달 모델링을 수행하였다. 이의 검증을 위하여 무부하 과속도 영역에서 계산된 코일 온도와 실험값을 비교하여 6.4%이하로 일치하였다. 35PN440 을 적용한 전동기에 비하여 15HTH100 을 적용한 전동기는 무차원 회전속도 0.9, 부하율 3.0 일 때 철손실이 84.4% 로 감소하였고, 무차원 코일 온도 1.0 을 기준으로 출력이 85.2% 향상되었다. 정격 구동 영역의 손실 측정 및 열전달 모델링으로 과부하 및 과속도 영역에서 철심재질에 따른 코일 온도 변화 및 전동기 출력 개선량을 정확하게 예측할 수 있음을 알 수 있다.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.117-124
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• 2011

Automotive engines require strategies to fulfill the emission regulations in terms of NOx and PM. A dramatic reduction in NOx and PM emissions could be achieved with high pressure injection, innovative combustion strategies and EGR. Recently, Lean NOx Trap (LNT) and Urea-SCR are considered as more practical strategy to suppress the engine-out emissions substantially for copying with severe regulation. These systems need to reduce the reducing agent injection system which has a huge impact on NOx purification efficiency. In this paper, different three injectors have been used to investigate spray characteristics and engine emission test was conducted to clarify the effect of these injectors on the NOx reduction.

• 한국전자통신학회논문지
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• 제5권6호
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• pp.613-619
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• 2010

최근 반송장치 시스템의 구동원으로 전기자 분산배치를 이용한 영구자석 리니어 동기 모터가 사용되고 있다. 하지만, 전기자 분산배치를 이용한 영구자석 리니어 동기 모터는 구조상 필연적으로 단부가 존재하게 된다. 이러한 이유로 전기자의 철심과 가동자의 영구자석 사이에 단부 코깅력이 발생한다. 본 논문은 유한요소법을 이용한 2차원 수치해석을 통해 단부 코깅력을 고찰하였다. 또한, 단부 코깅력을 최소화하기 위해 가동자에 보조극을 설치한 형상을 제안하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권4호
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• pp.152-160
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• 1999

A high speed motor has been generating a lot of attention due to its performance-more light, thin, short, compact than ordinary motors. But they have low efficiency with high frequency power source because of the iron losses which may produce too much heat as well as the copper losses occurred in the rotor windings. The Halbach array can generate the strong magnetic field systems without additional magnetic materials, therefore the iron losses can be removed. In this paper, the Halbach array is applied to the field system for the high speed motor, and three dimensional FEM is used to analyze the field of the Halbach array considering with the leakage flux. The measured values of flux density are also compared with the FEM analysis. And the magnetic characteristics of the Halbach array field system are compared with those of the conventional field systems such as slot-iron type, PM-iron type. Consequently, it is confirmed that the Halbach array field system is more suitable to the high speed motor because it has high flux density, sinusoidal flux distribution than others.