• 드라이브 ㆍ 컨트롤
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• 제13권1호
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• pp.10-17
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• 2016

e-4WD(Electric-4WD) system is a 4WD(4-Wheel Drive) System that can transform a car into a Hybrid System. e-4WD consists of a Motor, Inverter, Speed reducer and Clutch. The Motor, Speed reducer and Clutch are installed on the rear sub-frame as a chassis module type. The inverter is installed separately. Compared to a mechanical 4WD, the e-4WD system has many advantages. For example, the reduced number of drivetrain components makes better use of the space. Driving with a motor only at low speed improves fuel economy and reduces exhaust gas. Engine downsizing is available because the motor assists the engine. The performance of a conventional HEV(Hybrid Electric Vehicle) system can also be maintained. This paper proposes the specifications of components and the control logic for an e-4WD System. And the effect of the e-4WD system is proven using a test vehicle equipped with components under various test conditions.

• 드라이브 ㆍ 컨트롤
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• 제20권2호
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• pp.31-39
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• 2023

The aim of this study was to measure and analyze engine load factor (LF) according to working conditions (operation type and gear stage) of small agricultural multi-purpose cultivator to estimate the emission of air pollutants. To calculate LF, a torque sensor capable of collecting torque and rotational speed was installed on the engine output shaft and DAQ was used to collect data. A field test was conducted with major operation of a cultivator and tillage operations (plow tillage and rotary tillage). Engine power was calculated using engine torque and rotational speed and LF was calculated using real-time power and rated power. In addition, unified LF was calculated using the weight for each operation and the average LF for each operation. As a result, average LF values at 1.87 and 3.10 km/h by plow tillage were 0.50 and 0.69, respectively. Average LF values at 1.87 and 3.10 km/h by rotary tillage were 0.70 and 0.78, respectively. Furthermore, unified LF calculated in consideration of the weight factor showed a value of 0.65, which was 135% higher than the conventional LF (0.48). Results of this study could be used as basic information for realizing LF values in the field of agricultural machinery.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• Journal of Power Electronics
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• 제9권1호
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• pp.51-60
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• 2009

Hybrid Electric Vehicles (HEVs) utilize electric power as well as a mechanical engine for propulsion; therefore the performance of HEV s can be directly influenced by the characteristics of the Energy Storage System (ESS). The ESS for HEVs generally requires high power performance, long cycle life and reliability, as well as cost effectiveness. So the Hybrid Energy Storage System (HESS), which combines different kinds of storage devices, has been considered to fulfill both performance and cost requirements. To improve operating efficiency, cycle life, and cold cranking of the HESS, an advanced dynamic control regime with which pertinent storage devices in the HESS can be selectively operated based on their status was presented. Verification tests were performed to confirm the degree of improvement in energy efficiency. In this paper, an advanced HESS with improved an Battery Management System (BMS), which has optimal switching control function based on the estimated State of Charge (SOC), has been developed and verified.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.291-300
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• 1999

Currently under development is an airborne auxiliary power unit with 100 Kw equivalent power, which is composed of a centrifugal compressor, a reverse annular combustor, and a radial turbine. Air-foil bearings are used in this power unit to eliminate the oil supplying system, which can reduce the system complexity and weight. The high speed generator is adopted as an electric power generation and engine starting system, which can also eliminate the reduction gear system. Not only electric power but also pneumatic power is provided by bleeding the compressed air This power unit is aimed for the multi-purpose use such as a primary power unit In the army weapon system, an auxiliary power and environmental control unit in a next-generation tank, and a smoke generating unit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.69-70
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• 2017

This paper presents design of control system for permanent magnet synchronous generator(PMSG). The gas engine make rotating mechanical energy from gas fuel energy. The rotor of synchronous generator is connected to axis of engine. And it converts the mechanical energy to the electrical energy. The control system of PMSG helps the electrical energy to flow to grid. the single phase pfc rectifier controls the DC-link voltage by controlling the current of filter inductor. If the DC-link voltage is higher than the voltage reference, the filter current could be controlled to flow to grid. The three phase inverter controls the stator current of generator. The direction of the current is controlled depends on motoring or generating mode. The feasibility of the grid-connected PMSG is verified by the experimental results with 1kW prototype.

• Journal of Advanced Marine Engineering and Technology
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• 제18권2호
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• pp.113-121
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• 1994

Since two oil shocks in 1970s, all of engine makers have persevered in their efforts to reduce specific fuel consumption and to increase engine power rate as much as possible in marine diesel engines. As a result, the maximum pressure in cylinders of these engines has been continuously increased. It causes direct axial vibration. The axial stiffness of crank shaft is low compared to old types of engine models by increasing the stroke/bore ratio and its major critical speed might occur within engine operation range. An axial damper, therefore, needs to be installed in order to reduce the axial vibration amplitude of the crankshaft. Usually the main critical speed of axial vibration for the propulsion shafting system with a 4-8 cylinder engine exists near the maximum continuous revolution(MCR). In this case, when the damping coefficient of the damper is increased within the allowance of the structural strength, its stiffness coefficient is also increased. Therefore, the main critical speed of axial vibration can be moved beyond the MCR. It has the same function as a conventional detuner. However, in the case of a 9-12 cylinder engine, the main critical speed of axial vibration for the propulsion shafting system exists below the MCR and thus the critical speed cannot be moved beyond the MCR by using an axial damper. In this case, the damping coefficient of an axial damper should be adjusted by considering the range of engine revolution, the location and vibration amplitude of the critical speed, the fore and aft vibration of the hull super structure. It needs to clarify the dynamic characteristics of the axial vibration damper to control the axial vibration appropriately. Therefore authors suggest the calculation method to analyse the dynamic characteristics of axial vibration damper. To confirm the calculation method proposed in this paper, it is applied to the propulsion shafting system of the actual ships and satisfactory results are obtained.

• Journal of Advanced Marine Engineering and Technology
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• 제39권6호
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• pp.642-648
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• 2015

최근 선박에서 에너지 절감에 대한 많은 연구가 수행되고 있다. 그러한 연구의 일환으로 선박의 고정적인 부하를 제외한 변동 부하를 파악하고 제어함으로써 선박의 에너지를 절감할 수 있다. 기관실 팬 시스템은 대표적인 변동부하 중 하나이다. 기존 선박에서는 기관실 팬을 특별한 지침 없이 실 경험에 의해 정격운전으로 운용하고 있다. 이에 본 논문에서는 기관실 팬의 특성을 파악하고, 에너지 관리 시스템 중 하나로 ERFCS(Engine Room Fan Control System) 및 ERFCS 알고리즘을 제안하였다. ERFCS는 온도 및 압력에 따라 팬의 속도를 제어하며 부하 변화에 따라 팬의 운전 대수를 1대에서 4대 사이로 조절한다. 또한 기관실 팬의 최소 회전속도를 50%로 제한하여 낮은 RPM(Revolution Per Minute)에서 기계적 마찰, 발열 등의 이유로 팬이 손상을 입거나 낮은 압력으로 팬에 서징(surging) 현상이 발생하지 않도록 한다. 제안된 알고리즘과 ISO 8861을 바탕으로 LabVIEW를 사용한 팬 제어 시스템 시뮬레이션을 개발하였다. 결론적으로, 구현된 시뮬레이션을 통해 제안된 팬 제어 시스템이 기존 사용 방식에 비해 46.4%만의 동력만으로도 운전이 가능함을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.746-753
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• 2004

In this paper, the Power Management System(PMS) which based on a decision making system according to power strategy is proposed and implemented. PMS is designed to have functions of power monitoring. controlling, synchronizing load sharing and monitoring of driving engine, etc. PMS consists of the internet communication system(ICS). Remote Management System(RMS) and Sensor Driver System (SDS) ICS transmits the monitoring and supervisory data via Internet to Remote Management System(RMS) in real-time SDS detects various power system data on local generator and utility via I/O interface system. I/O interface system receives various status data and outputs control signals. Implemented PMS is tested with dummy signal to verify proposed functions and shows good results. For future study implemented PMS will be tested under real load condition to merchandize.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.761-768
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• 2018

In this paper, the performance analysis of a control topology based on the direct output power control (DPC) for robust and inexpensive permanent magnet-assisted synchronous reluctance generator (PMa-SynRG) system is presented. The PMa-SynRG might be coupled to an internal combustion engine running at variable speed. A three-phase PWM rectifier rectifies the generator output and supplies the dc link. A single-phase PWM inverter supplies constant ac voltage at constant frequency to the grid. The overall control algorithm is implemented on a TMS320F2812 digital signal processor board. Simulations results and experimental results verify the operation of the proposed system.