• 한국자동차공학회논문집
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• 제24권6호
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.379-384
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• 2004

A prototype of 750 kW direct-drive wind turbine generator system, KBP-750D is under development in Korea. For the gearless, direct-drive prototype a synchronous generator with permanent magnets has been developed. The upwind 3-blade type machine employs variable speed and pitch control. The operating ranges of wind and rotor speed are 3 to 25 m/s and 9 to 25 rpm, respectively. The tip speed ratio of rotor blade is 7.5, designed for power coefficient 0.47, The blade pitch and torque are controlled with the predefined torque-speed curve according to the conditions of wind and public electric grid. This paper describes the outlines of primary components of KBP-750D.

• Journal of Magnetics
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• 제18권4호
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• pp.443-453
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• 2013

Maglev wind turbine generator (MWTG) technology has been widely studied due to its low loss, low maintenance cost, and high reliability. However, the dynamics of the magnetic bearing system differ fromthe those of the traditional mechanical bearing system. A horizontal axial MWTG supported with a permanent magnetic bearing is designed in this research and the radial forces and the natural frequencies of the rotor system are studied. The results show that the generatorhas a cyclical magnetic forceand an unreasonable bearing stiffness may mean that the rotor system needs to work in the resonance region; the bearing stiffness is the key factor to avoid this problem. This is the main rule of the bearing stiffness design in the MWTG, and this rule can also be used in other maglev permanent magnet motors.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.1022-1035
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• 2016

A double-tube once-through steam generator (DOTSG) consisting of an outer straight tube and an inner helical tube is studied in this work. First, the structure of the DOTSG is optimized by considering two different objective functions. The tube length and the total pressure drop are considered as the first and second objective functions, respectively. Because the DOTSG is divided into the subcooled, boiling, and superheated sections according to the different secondary fluid states, the pitches in the three sections are defined as the optimization variables. A multi-objective optimization model is established and solved by particle swarm optimization. The optimization pitch is small in the subcooled region and superheated region, and large in the boiling region. Considering the availability of the optimum structure at power levels below 100% full power, we propose a new operating scheme that can fix the boundaries between the three heat-transfer sections. The operation scheme is proposed on the basis of data for full power, and the operation parameters are calculated at low power level. The primary inlet and outlet temperatures, as well as flow rate and secondary outlet temperature are changed according to the operation procedure.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.6-10
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• 2016

In RF plasma processing, when the plasma is generated, there is the difference of impedance between RF generator and plasma source. Its difference is normally reduced by using the matcher and the RF power is transferred efficiently from the power generator to the plasma source. The generated plasma has source impedance that it can be changed during processing by pressure, frequency, density and so on. If the range of source impedance excesses the matching range of the matcher, it cannot match all value of the impedance. In this research, we studied the elevation mechanism of the RF power delivery efficiency between RF generator to the plasma source by using the transmission line and impedance tuning of the plasma source. We focus on two plasma sources (capacitive coupled plasma (CCP), inductive coupled plasma (ICP)) which is most widely used in industry recently.

• 대한전자공학회논문지SD
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• 제38권6호
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• pp.446-455
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• 2001

본 논문은 GPS 수신기를 이용한 정밀 동기 클록 발생기의 PLD 구현에 관한 것이다. GPS 수신기에서는 동기화 된 IPPS 신호를 발생하는데, 이를 이용하여 시각동기와 클록 보정 등을 행할 수 있다. 본 연구에서는 저가격의 오실레이터로부터 높은 정확도의 클록을 발생시킬 수 있는 DPLL 구조의 정밀 동기 클록 발생기를 ALTERA FLEX EPM6016TC144-3 PLD를 이용하여 구현하였다. 이를 이용하여 GPS 수신기를 함께 이용하여 높은 정밀도를 가지며 동기화 된 1MHz 클록을 발생시키는 하드웨어를 설계하고 구현한다.

• 대한전자공학회논문지TC
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• 제41권2호
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• pp.65-70
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• 2004

본 논문에서는 비선형 RF(Radio Frequency) 증폭기의 선형화를 위한 새로운 구조의 전치왜곡 선형화기를 제안한다. 전치 왜곡에 이용되는 3차 비선형 성분은 RF 신호의 포락선(envelope) 전력을 이용하여 발생시킨다. 3차 왜곡 성분 발생기(3rd order distortion generator)는 FET로 구성되었고, 왜곡 신호 발생 후 남아 있는 주 신호 성분 제거를 위해 평형 결합 구조를 제시하였다. 발생된 3차 혼변조 신호는 RF 대역에서 진폭과 위상을 조절함으로써 최적의 선형화 조건을 만족시킨다. 2-tone 실험결과 증폭기의3차 흔변조특성이 30～40㏈ 개선되었다. IS-95 CDMA 신호 실험 결과 인접 채널 전력 비(ACPR)가 약 l0㏈이상 개선됨을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.275-278
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• 2017

차량의 교류발전기는 성능 및 효율에 따라 자동차의 연비와 배기가스에 많은 영향을 준다. 효율을 개선시키고 연비를 향상시키려는 노력은 자동차업체및 업체를 중심으로 계속되고 있다. 본논문은 A교류 발전기의 설계절차를 정리하고 같은 크기의 교류발전기에서 출력을 최적화하는 인자를 발굴하여 실차의 조건에서 충방전 Simulation을 통해 Energy Balance를 검증하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권3호
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• pp.91-97
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• 2006

A major difficulty with the practical application of the multiple observer based IFDI schemes is the computational burden of the residual generation. In this paper, a new residual generator that employs function observers is proposed to reduce the computational burden, and the design methods of the IFDIS, equipped with the residual generator, are presented. The function observers employed in the residual generator can be considered as a dual of the unknown input (function) observer And it can be designed to estimate the measurement errors that are due to sensor faults. The error estimates are further processed to generate the residuals by which reliable fault detection/isolation result car be obtained. The proposed scheme is more useful, in real-time application, than any other multiple state observer based IFDISs. It can be effectively applied to fault tolerant control because the failure effects can be compensated by the use of the estimates of measurement errors. The proposed IFDI scheme is applied to an inverted pendulum control system for the IFDI of failed sensor and fault compensation.

• Journal of Magnetics
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• 제20권2호
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• pp.148-154
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• 2015

48-V ISG (Integrated Starter Generator) system has attracted attention to improve the fuel efficiency of ICE (Internal Combustion Engine) vehicle. One of the key components that significantly affects the cost and performance of the 48-V ISG system is the motor. In an ISG motor, the core and copper loss make the motor efficiency change because the motor has a broad driving operated range and more diverse driving modes compared with other motors. When designing an ISG motor, the selection of an electrical steel sheet is important, because the electrical steel sheet directly influences the efficiency of the motor. In this paper, the efficiency of the ISG motor, considering core loss and copper loss, is analyzed by testing different types of electrical steel sheets with respect to the driving speed range and mode. Using the results of a finite element method (FEM) analysis, a method to select the electrical steel sheet is proposed. This method considers the cost of the steel sheet and the efficiency according to driving mode frequency during the design process of the motor. A wound rotor synchronous machine (WRSM) was applied to the ISG motor in this study.