• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.800-801
• /
• 2015

본 논문에서는 표면부착형 영구자석 동기발전기(SPMSG)의 소음과 진동의 원인이 되는 토크 리플을 저감하고자 하였다. 최적설계법의 하나인 반응표면법을 이용하여 토크 리플을 최소화하는 발전기 형상을 결정하였다. 반응표면법은 통계적인 근사방법으로써 여러 개의 독립변수 또는 설계변수가 복합적으로 작용하여 해석적 모형을 만드는데 매우 유용한 방법이다. 또한 유한요소해석법을 통하여 기존모델과 최적설계모델의 토크 리플을 비교함으로써 성능 개선을 확인하였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 전력전자학술대회 논문집
• /
• pp.134-137
• /
• 1998

In this paper, a hybrid maximum power tracker for a photovoltaic/wind hybrid power system is proposed. In the hybrid system, a direct interfacing the wind power system to the photovoltaic system gives the problems of voltage fluctuations, poor maximum power tracking, and harmonics generation associated with the random wind speed, the random solar irradiation and the pulsating torque came from the wind turbine synchronous generator and photovoltaic. To overcome these problems, a wind side DC/DC converter are proposed employing a star/delta transformer interconnected between the wind turbine side and the photovoltaic side. The control objective for each dc/dc converter is to extract maximum power from each different photovoltaic system and wind system, and transfer two different powers to the inverter and load.

• 신재생에너지
• /
• 제1권4호
• /
• pp.55-59
• /
• 2005

In this paper, a new drive system(SHS) for hybrid electric vehicle is proposed. As dual rotor hybrid electric vehicle using planetary gearsets, the SHS has the advantages of both series and parallel systems. The output speed and torque of SHS can be determined at specific point regardless of the engine's operating point. When the size of generator which is used in SHS is same as in THS, the SHS has more activities of engine control due to the ability that is operated in lower speed range. To maximize the performance of system, we carried out optimization for the three parameters that are engine, motorl and motor2. As the result of the optimization, we confirmed the SHS is more preferable to THS in fuel consumption and acceleration area.

• 대한기계학회논문집B
• /
• 제30권9호
• /
• pp.858-865
• /
• 2006

SMART Pilot is a multipurpose small capacity integral type reactor. Main coolant pump (MCP) of SMART Pilot is a canned-motor-type axial pump to circulate the primary coolant between nuclear fuel and steam generator in the primary system. The reactor is designed to operate under condition of $310^{\circ}C$ and 14.7MPa. Thus MCP has to be tested under same operating condition as reactor design condition to verify its performance and safety. In present wort a test apparatus to simulate real operating situations of the reactor has been designed and constructed to test MCP. And then functional tests, performance tests, and endurance tests have been carried out upon a prototype MCP. Canned motor characteristics, homologous head/torque curves, coast-down curves, NPSH curves and lift-time performance variations were obtained from the qualification test as well as hydraulic performance characteristics of MCP.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
• /
• pp.73-76
• /
• 2001

This paper presents a new systematic contingency selection, screening and ranking method for on-line transient security assessment. Transient stability of a particular generator is influenced most by fault near it. Fault at the transmission lines adjacent to the generators are selected as contingency. Two screening methods are developed using the sensitivity of modal synchronizing torque coefficient and computing an approximate critical clearing time(CCT) without time simulation. The first method, which considers only synchronizing power, may mislead in some cases since it does not consider the acceleration power. The approximate CCT method, which consider both the acceleration and deceleration power, worked well. Finally the Single Machine Equivalent(SIME) method is implemented using IPLAN of PSS/E for detailed stability analysis.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 추계학술대회 논문집
• /
• pp.5-9
• /
• 2004

본 논문에서는, 벨트 연결형 기동발전기(Integrated Starter Generators)를 이용하여 승용 자동차에서 엔진 기동 시 발생하는 토크 맥동을 억제하는 방법을 제안하였다. 기동발전기의 빠른 토크 응답성을 통하여 내연기관의 기동 시 발생하는 저 주파수의 진동을 억제하여 승용차의 승차감을 개선하고자 한다. 특히 벨트를 통하여 구동되는(또는 구동하는) 벨트 연결형 기동발전기에 있어 벨트의 특성 분석과 모델링을 통하여 효과적인 맥동토크 억제 법을 제시하였다.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제13권1호
• /
• pp.55-63
• /
• 2013

For a reliability assessment of large machinery parts, reliable data should be obtained from testing many samples for a long time. However, in case of testing these samples, testing cost is excessive; in case of life test for long time, power consumption is high; and in case of accelerated test by over load, very high cost is required to build the life testing device. Especially it is very frequent that the expensive device's life has ended during a accelerated test by over load. In this study, the design mechanism of the life testing device which excels in energy saving during the reliability test of large machinery parts has been introduced.

• 한국유체기계학회 논문집
• /
• 제9권5호
• /
• pp.28-35
• /
• 2006

Orbiter mechanism has been applied to vacuum pump design for small oxygen generator where low vacuum of about 200 mmHg is required. Performance of the designed vacuum pump has been numerically investigated: calculated volumetric and adiabatic efficiencies were 69.7% and 83.9%, respectively for leakage clearance of $10{\mu}m$. Total efficiency of the orbiter vacuum pump was 77.5%. At the shaft speed of 1700 rpm suction displacement volume of 6.3cc provided discharge flow at the rate of 2.3 liter/min with power consumption of 10.1Watt. Torque variation of the orbiter pump was only about 20% of that of diaphragm pump.

• Structural Engineering and Mechanics
• /
• 제6권4호
• /
• pp.457-466
• /
• 1998

The dynamic response of an elastic torsion shaft of revolution is analysed by the Line-Loaded Integral Equation Method (LLIEM). A "Dynamic Point Ring Couple" (DPRC) is used as a fictitious fundamental load and is distributed in an elastic space along the axis of the shaft outside the shaft occupation. According to the boundary condition, our problem is reduced to a 1-D Fredholm integral equation of the first kind, which is simpler for solving than that of a 2-D singular integral equation of the same kind obtanied by Boundary Element Method (BEM), for steady periodically varied loading. Numerical example of a shaft with quadratic generator under sinusoidal type of torque is given. Formulas for stresses and dangerous frequency are mentioned.

• KIEE International Transactions on Power Engineering
• /
• 제4A권4호
• /
• pp.178-191
• /
• 2004

This paper presents a new approach to HVDC system control for damping subsynchronous oscillation (SSO) involving HVDC converters and turbine generator shaft systems. This requires a novel eigenvalue analysis (NEA) program, derivation of HVDC system modeling considering steady-state conditions and dynamic conditions in the combined AC/DC system, and an appropriate control scheme. The method suggested makes possible the design of a subsynchronous oscillation damping controller (SODC) to provide positive damping torque for the range of torsional modes in combined AC/DC systems. There are three steps involved in the design of a SODC； first the worst torsional mode is determined using the NEA program, next the SODC parameters are designed for the range of that torsional mode, and then finally an off-line simultaneous time domain program such as PSCAD/EMTDC is used to verify the parameters of the SODC. The suggested SODC design method is applied to two AC/DC systems, and its practicality is verified using the PSCAD/EMTDC simulation program.