• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.993-1002
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• 2022

This paper relates to a method of modeling the thrust dynamic load caused by the thrust variation occurring on the blade due to the tower shadow below the rated wind speed. A method that uses thrust coefficient is presented by introducing "tower shadow coefficient of thrust variation". For a 2MW wind turbine, the values of "tower shadow coefficient of thrust variation" are calculated and analyzed at wind speeds below the rated. The dynamic load model of thrust under tower shadow is evaluated in Matlab/Simulink using the obtained "tower shadow coefficient of thrust variation" and thrust coefficient. It shows that the thrust variations acting on the three blades by the tower shadow can be expressed using both the thrust coefficient and the introduced "tower shadow coefficient of thrust variation".

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.141-145
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• 2003

The linear motor available for linear transition motion, because of its advantages, the motor design and its application have gradually increased, but the quantitative measurement system of thrust force has not been generalized. So, this paper proposes the modeling, computation method, and measurement system of linear thrust force in HB-type linear pulse motor. As the computation method of thrust force in linear motor is presented and the measurement system is designed, and manufactured, it would be verified that reliability of measurement method and measurement system, considering on and comparing the results of mathematical modeling with measured values of static thrust force and dynamic one.

• 로봇학회논문지
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• 제2권2호
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• pp.109-118
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• 2007

The thruster is the crucial factor of an underwater vehicle system, because it is the lowest layer in the control loop of the system. In this paper, we propose an accurate and practical thrust modeling for underwater vehicles which considers the effects of ambient flow velocity and angle. In this model, the axial flow velocity of the thruster, which is non-measurable, is represented by ambient flow velocity and propeller shaft velocity. Hence, contrary to previous models, the proposed model is practical since it uses only measurable states. Next, the whole thrust map is divided into three states according to the state of ambient flow and propeller shaft velocity, and one of the borders of the states is defined as Critical Advance Ratio (CAR). This classification explains the physical phenomenon of conventional experimental thrust maps. In addition, the effect of the incoming angle of ambient flow is analyzed, and Critical Incoming Angle (CIA) is also defined to describe the thrust force states. The proposed model is evaluated by comparing experimental data with numerical model simulation data, and it accurately covers overall flow conditions within 2N force error. The comparison results show that the new model's matching performance is significantly better than conventional models'.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.358-360
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• 1996

LPM(Linear pulse motor) has made linear motions by itself. And the LPM has higher thrust force ratio to mass and more wide driving speed lunges comparing with the conventional rotating type motors. However, there are the thrust force ripples in the LPM, which are produced by the mechanical structures and nonlinear back emf. It makes to hesitate the practical applications of LPM. Especially, it becomes needed to reduce the thrust force ripples for practical, which needs relative low driving speeds. For reducing the thrust force ripples, in the first place, it was built a new nonlinear linkage flux equations of the LPM. In these equations, the influence of permanent magnetic and variable reluctance thrust force components were considered. In this paper, some experimental results in the modeling of LPM are shown and detent lone and holding force characteristics of LPM are measured.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.414-416
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• 2009

In order to build a transient simulation program for a high thrust liquid rocket engine(LRE), a static performance simulation program for components were made. The components were the thrust chamber (combustion chamber and supersonic nozzle), centrifugal pump (impeller and volute casing), impulse turbine, and flow control devices (control valve and orifice). Simplified mathematical models based on classical thermodynamic and inviscid theories were used to remove complexity and enhance the utility of the program. We examined the results of each program qualitatively for validate each component modeling.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.527-532
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• 1993

Generally the method of depth controlling is classified into buoyancy control and thrust control. In this study, we employed thrust control system. And mathematical modeling and computer simulation are performed in order to design auto depth control system for underwater vehicle. Consequently, the specifications of components are determined, and the performance of system is analyzed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.45-49
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• 1998

In this paper, the direct thrust control of PWM Inverter-fed Single-sided Linear Induction Motor (hereinafter referred to as "SLIM") is achieved with Space Vector control and PI control. The trembling of air gap length which is occured between the primary winding core and the secondaty structure of the SLIM must be minimized in order to get quick response characteristic. First, voltage equations of SLIM are shown on the suitable d-q axis equivalent circuits which analyze characteristics of the thrust and the normal force. Also, modeling and analysis of the d-q axis equivalent circuits are able to make robust transient thrust from the current regulation in the equivalent circuits. These results exemplified the direct drive of SLIM with the reference speed and thrust were verified by the experiments.periments.

• 한국항공운항학회지
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• 제20권2호
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• pp.1-6
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• 2012

Four dimensional(4-D) trajectory modeling is conducted based on flight plan. The flight plan is divided into several segments which represent certain operating flight modes. Thrust, drag and fuel consumption rate of an aircraft are calculated using BADA provided by Eurocontrol. The trajectory is modeled with the rate of climb/descent calculated with Total-Energy Equation. The simulation results with a typical aircraft and its flight plan indicate that the trajectory modeled corresponds well with the suggested flight plan. The performance profiles including total endurance time and time history for speed, thrust, drag and fuel consumption were also appropriately generated.

• 대한기계학회논문집A
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• 제40권4호
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• pp.407-414
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• 2016

풍력터빈이 MW급으로 대형화되면서 블레이드의 길이가 40미터 이상으로 길어지게 되어, 로터 블레이드가 회전할 때 블레이드에 발생하는 비대칭하중이 증가하게 되었다. 윈드쉬어, 타워 섀도우, 난류풍속 같은 요소들은 블레이드에 이런 비대칭하중 발생에 영향을 미친다. 본 논문은 원드쉬어로 인해 블레이드에 발생하는 추력변동에 의한 동하중을 추력계수를 이용하여 모델링하는 방법에 관한 것이다. 이를 위하여 "윈드쉬어 추력변동 계수"를 정의 및 도입하고, 2MW 육상용 풍력터빈을 대상으로 정격이하의 풍속에서 윈드쉬어 추력변동 계수값을 구하여 분석한다. 구해진 "윈드쉬어 추력변동 계수"와 추력계수를 이용하여 Matlab/Simulink에서 윈드쉬어 동하중 모델을 구현하고, 윈드쉬어에 의해 세 블레이드에 작용하는 추력변동을 추력계수와 "윈드쉬어 추력변동 계수"를 동시에 이용하여 표현할 수 있음을 보인다.

• 한국추진공학회지
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• 제26권4호
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• pp.44-53
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• 2022

추력조절이 가능한 고체추진기관에서 감압률은 추력중단 성능에 가장 큰 영향을 미치는 인자이다. 본 연구에서는 몇 종류의 추진기관에서 구현 가능한 감압률의 범위를 파악하였으며 이를 통하여 추진기관 감압률에 미치는 주요 인자를 도출하였다. 추진제에 대한 소화특성 파악뿐만 아니라 추진기관의 목표성능을 만족할 수 있는 감압률을 파악하는 것이 실제 추력조절 시스템 설계에 중요하며 본 연구에서와 같은 감압률 모델획득 방법론은 추력중단이 필요한 고체추진기관 설계에 적용 가능할 것으로 판단된다.