• Journal of Power Electronics
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• 제13권4호
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• pp.528-535
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• 2013

Most eco-friendly cars can adopt the concept of an integrated battery charger (IBC), which uses currently available motor drive systems. The IBC has a lot of strong points such as low cost and minimum space for the high voltage battery charger. On the other hand, it also has some defects caused by its structure. In this paper, the shortcomings of the conventional IBC for PHEVs with interior permanent magnet motors are discussed, and two advanced IBCs with improved performance are presented. Compared with the conventional IBC, the two advanced IBCs have plenty of strengths such as low common noise, high efficiency, simple sensing methods, etc. Then, the digital control algorithm is modified and a power loss calculation is carried out with simulation software. Finally, experimental results are provided to show the performance of the IBC systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.271-273
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• 2001

This paper presents a adaptive speed controller for field oriented controlled (FOC) permanent magnet synchronous motor (PMSM) drives. However, achieving FOC requires machine specific knowledge, and tracking of drifting motor parameters in order to maintain control. The proposed controller based on Minimum Controller Syntheses (MCS) algorithm does not require exact knowledge of motor parameters. This controller structure simplifies the design and implementation of the adaptive controller requiring less effort to synthesis than a standard MRAC system. Simulation results using Matlab/Simulink show that the proposed controller has good dynamic performances and it is insensitive to parameter variations.

• Journal of the Optical Society of Korea
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• 제8권3호
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• pp.127-131
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• 2004

This paper investigates applications of femtosecond lasers for the micromachining of transparent materials and fabrication of optical devices. We show commercial micromachining examples of transparent materials which have been fabricated for various applications. Near infrared femtosecond laser processing is an attractive method to fabricate three-dimensional optical waveguides into various transparent materials. Focused femtosecond laser pulses induce a permanent refractive-index change only near the focal point. We also demonstrate a Y coupler with the splitting ratio of 1:1 written by femtosecond laser pulses into a fused silica glass. The minimum propagation loss of 0.8 ㏈/㎝ awl the refractive-index change of 0.006-0.01 at the wavelength of 1550 ㎚ were achieved by optimization of the laser fluence.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.238-239
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• 2013

It is a crucial requirement to utilize an economical battery capacity for the wind energy conversion system. In this paper, the optimal BESS capacity is determined for the wind farm whose dispatched power is assigned by the min-max dispatching method. Based on a lifetime cost function that indicates the BESS cost spent to dispatch 1kWh wind energy into grid, the battery capacity can be optimized so as to obtain the minimum system operation cost. Moreover, the battery state of charge (SOC) is also managed to be in a safe operating range to ensure the system undamaged. In order to clarify the proposed optimizing method, a 3MW permanent magnet synchronous generator (PMSG) wind turbine model and real wind speed data measured each minute are investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.397-399
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• 1999

This paper deals with the torque characteristics of a AFPM motor excited by permanent magnets. According to relative angle difference of two rotor, torque characteristics are studied. According to varied angle of two rotor, torque ripple and, total torque of AFPM motor is different. For minimum torque ripple, angle of two rotor of AFPM motor are investigated. For this study, we used to Maxwell EM 3D program. A prototype AFPM motor have been assembled and driving power supply are made. Characteristics of magnetical and electrical characteristic are investigated.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.97-102
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• 2005

This paper presents feed rate optimizaton of a PMLSM driven feed-slide for mininum vibrations by smoothing velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• 아시안잔디학회지
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• 제10권1호
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• pp.31-40
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• 1996

The mechanical expresion provides for the use of Soil property reserves and permanent protec-tion or improvement of soil resources in accordance with measurable standards. If the functions I (initial soil property), E (soil erosion), R (soil renewal), and M. (minimum allowable value) are assumed to be integrable in region A, erosion tolerance over a region is leaded to ${\int}_A{\int}I(m, cl, re, ch, b)dA-{\int}_A{\int}{\{\int}_{to}^{\infty}[E(w, re, c, re, ch, b, t)-R(m, ch, re, b, t)]dt}\dA{\geqq}{\int}_A{\int}M_i(m, cl, re, ch, b)dA$ were variable factors are m=parent material of soil, cl=climate, re=relief or topography, ch=soil characteristics, r=rain or water, w=wind, b=biota, and t=time.

• 한국건설관리학회논문집
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• 제23권5호
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• pp.108-116
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• 2022

1989년 영구임대주택으로 시작된 공공임대주택 정책은 매 정부마다 새로운 공급유형을 도입하며 입주대상과 재고량을 확대하고 있다. 하지만 공공임대주택 사업주체는 공공임대주택의 적자누적으로 공급확대에 어려움을 겪고 있다. 본 연구에서는 장기공공 임대주택 재건축사업을 기존 장기공공임대주택사업의 누적적자 보전방안으로 제시하였다. 재건축사업으로 공급되는 분양주택 수익으로 누적적자를 보전할 수 있는 재건축사업의 용적률을 최소용적률로 정의하고, 장기공공임대주택 재건축사업의 특성을 고려한 수리적 접근으로 장기공공임대주택 재건축사업 최소용적률 수리모델을 제시하였다. 최소용적률 수리모델의 결정요인은 기존 장기공공임대주택 누적적자, 재건축사업 분양주택 토지면적, 단위면적당 분양가격, 단위면적당 사업비로 구성된다. 최소용적률 수리모델은 노후 장기공공임대주택 재건축사업의 건축규모에 대한 경제적 측면의 의사결정 지원과 도심지 내 주택공급 확대와 관련된 의사결정을 지원하는 이정표가 될 것으로 사료된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 추계학술대회
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• pp.311-316
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• 2004

LMTT는 항만 자동화를 위한 수평 이송이 가능하도록 설계된 셔틀카(shuttle car)와 격자구조의 레인에 부착된 스테이터 모듈 (stator module)로 구성된 PMLSM(Permanent Magnetic Linear Synchronous Motor)에 의해 구동된다 본 논문에서는 강도기준을 고려하고 경량화 설계를 위하여 셸(shell) 요소로 유한요소 모델링된 이동체(mover)의 구조최적설계를 수행하였다. 설계변수로는 가로 빔, 세로 빔, 휠 빔의 두께와 높이 방향의 치수를 결정하는 형상 변수를 포함시켰다. 목적함수로는 중량, 제한조건 함수로는 안전율이 고려된 응력으로 실정하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제2권5호
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• pp.310-316
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• 2013

This paper reports a sinusoidal $180^{\circ}$ drive for a permanent magnet (PM) brushless motor employing automatic angle compensator to suppress the driving loss during the wide-range load operation. The proposed drive of the sinusoidal $180^{\circ}$ PM Brushless motor reduced the amplitude of the 3-phase current by compensating for the lead-angle of the fundamental waves of the 3-phase PWM signal. The conventional lead-angle method was implemented using the fixed angle or memorized table, whereas the proposed method was automatically compensated by calculating the angle of the current and voltage signal. The algorithm of the proposed method was verified in a 30 W PM brushless motor system using a PSIM simulator. The efficiency of the conventional method was decreased 90 % to 60 %, whereas that of proposed method maintained approximately 85 % when the load shift was 0 to $0.02N{\cdot}m$. Using an FPGA prototype, the proposed method was evaluated experimentally in a 30 W PM brushless motor system. The proposed method maintained the minimum phase RMS current and 79 % of the motor efficiency under 0 to $0.09N{\cdot}m$ load conditions. The proposed PM brushless motor driving method is suitable for a variety of applications with a wide range of load conditions.