• Journal of Advanced Marine Engineering and Technology
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• 제13권3호
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• pp.26-36
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• 1989

Recently digital governor system is commonly adapted for the speed control of the marine diesel engine because of too much fluctuation of rpm resulted by the low speed, long stroke, high efficiency and a small number of cylinder of it, and versatile studies on the development of digital governor system are progressed. On this subject the new control method in which the fuel is controlled by feedforwarding the change of load as well as the feedback of angular velocity in case of disregarding the engine dead time and influence of scavenging air was proposed by the authors, and found the method has shown quite a good control performance in comparision to the conventional control method by the simulation using a digital computer for various load change. In this paper the speed control system of a diesel engine is simulated in case of regarding the engine dead time by the proposed method, and also confirm a good control performance of it under even more realistically simulated environment.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.251-259
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• 2002

The design concept of diesel engines for sea-going ships has been directed to Low-speed/Long-Stroke type to improve the efficiencies of combustion and propelling. But the time-delay property inevitable at such low speed engines gives much difficulties for governors to control the engine speed because they would be apt to go into unstable region especially when operating at low speed. The purpose of this paper is to study the problem of how the governor gain can be calculated dynamically in accordance with the variance of engine speed at least for an engine to be stable. In this study, the property of diesel engine was described as composed of combustion element including dead time and rotating element, and the ultimate gain for the speed control system to be located on the condition of stability limit was proposed based on the frequency characteristics. And the target gains with optimized stability also were proposed by giving proper margin to these ultimate conditions. The results were applied to a model system and the availability was confirmed to be satisfactory.

• Journal of Advanced Marine Engineering and Technology
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• 제26권5호
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• pp.565-572
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• 2002

The design concept of diesel engines for sea-going ships has been directed to Low-speed/Long-Stroke type to improve the efficiencies of combustion and propelling. But time-delay inevitable at low speed gives much difficulties for governors to control the engine speed because they would be apt to go into unstable region especially when operating at low speed. The purpose of this paper is to study the problem of how the governor gain can be calculated dynamically in accordance with the valiance of engine speed to locate the engine still on the properly stable condition. In this study, the property of diesel engine was described as composed of combustion element including dead time and rotating element, and the ultimate gain for the speed control system to be located on the condition of stability limit was proposed based on the frequency characteristics. And the target gains with optimized stability also were proposed by giving proper margin to these ultimate conditions. The results were applied to a model system and the availability was confirmed to be satisfactory.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.66-67
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• 2011

하이브리드 발전 시스템에서 전압과 주파수제어는 서로 다른 분산전원의 동기화 및 전력제어에 있어 매우 중요하다. 본 논문에서는 하이브리드 시스템 디젤 발전기의 연료 분사량을 조절하는 액추에이터의 전류제어를 위한 디지털 Governor의 제어 알고리즘을 구현하고, 제어기 개발을 통해 부하 가변 시에도 안정된 주파수 값을 얻어내어, 발전기의 운전영역에서 안정된 속도제어가 이루어지는 가를 시뮬레이션을 통해 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.776-777
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• 2011

조속기는 수차발전기의 핵심을 담당하는 두뇌라고 말할 수 있으며, 전력계통의 부하(주파수)가 변할 경우 수차발전기의 회전속도를 정격으로 유지시켜 양질의 전기를 생산하도록 항시 조정되는 역할을 한다. 최근 조속기는 디지털화되어 최적제어 감시 및 보호기능을 수행하고 있으나 문제점도 하나둘씩 나타나고 있는 실정이다. 본 논문에서는 디지털 가버너의 Isolation Mode에 대한 설명과 사고사례를 통해 디지털가버너 운영 시 문제점을 분석, 검토하여 보완하고자 하였으며, 이를 통해 안정적으로 전력공급을 주요 목적으로 하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제12권4호
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• pp.53-61
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• 1988

Speed of a diesel engine is usually controlled by the hydraulic governor which uses the centrifugal force of rotating fly balls for sensing the error speed. But for a recently developed high efficient, low speed and long stroke 2 cycle marine diesel engine, this governor doesn't work well enough because of too much changes of toraring force during one revolution of engine and too long uncontrollable time due to small numbers of cylinder. For improvement of jiggling phenomena and unstability various studies are being carried out, but they are not enough for a steep load change in a small ship's generator plant or at rough sea condition in a propulsion engine. In this paper, authors propose a new method to control a fuel before the change of angular velocity due to load change by feedforward the change of load, and find that the proposed method shows quite a good control performance in comparision to the customary PID control method by simulation using a digital computer for the various load change.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2153-2155
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• 2001

This thesis presents a development of intelligent digital governing system and it's application on Sumjingang Hydro-Power plant. The developed system consists of hardware, software and governing algorithm. The feature of hardware is triplex-modular fail safe redundant system for a safe turbine running. The software consists of operating system and application program. The operating system has real-time and multi-tasking features. And also, application algorithm is composed to run francis type hydro-turbine. The developed digital governing system is applied to Sumjingang hydro-power plant, Korea Hydro Nuclear Power Corporation.

• 전기학회논문지
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• 제58권6호
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• pp.1100-1104
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• 2009

As national power consumption every year increases, the power plant which is in the process of planning tries to establish high-capacity generator. The power system tends to become a large size. With the progress of electronic components, the control systems of the generator have been digitalized and rapid-response control system is possible. However, the minute frequency vibration of grid occurred with the effect of rapid-response control system. To solve these problem, PPS(Power System Stability) has been introduced since 2004, and it has being installed and applied to the thermal and nuclear power plant which are high-capacity, over 800MVA. However the minute frequency vibration is gradually changed to the bigger frequency vibration by fast-action control system, and this regional frequency fluctuation might be diffused wide area. Therefore, it is applied to the hydro generator which is small with fast-action governor system, and it is necessary to control the minute frequency vibration to prevent to diffuse. In this paper, the effect will be proved by establishing PSS on the Hydro-Generator which has both digital excitation and governor system for the first time in Korea.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.27-35
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• 1996

The ship's propulsion efficiency depends upon a combibation of engine and propeller. The propeller has better efficiency as the engine has lower rotational speed. This situation led the engine manufacures to design the engine that has lower speed, longer stroke and a small number of cylinders. With this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variations of the delay-time and the parameter perturbation especially in low speed engine. In this study we consider the perturbations of the engine parameters as the modeling uncetainties and design a robust speed controller for marine medium speed diesel engine by means of $ extit{H}_{infty}$control theory having the central solution. By comparing the results of the robust speed controller with those of mechanical governor and PID controller, the validity of the robust speed controller under parameter variations is confirmed. The speed control of the experimental diesel engine of carried out using actuator which is composed of PWM signal generator and D.C servo motor.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.349-349
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• 1996

The ship's propulsion efficiency depends upon a combibation of engine and propeller. The propeller has better efficiency as the engine has lower rotational speed. This situation led the engine manufacures to design the engine that has lower speed, longer stroke and a small number of cylinders. With this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variations of the delay-time and the parameter perturbation especially in low speed engine. In this study we consider the perturbations of the engine parameters as the modeling uncetainties and design a robust speed controller for marine medium speed diesel engine by means of $ extit{H}_{infty}$control theory having the central solution. By comparing the results of the robust speed controller with those of mechanical governor and PID controller, the validity of the robust speed controller under parameter variations is confirmed. The speed control of the experimental diesel engine of carried out using actuator which is composed of PWM signal generator and D.C servo motor.