• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.226-230
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• 2010

본 논문에서는 배터리와 전기모터 방식의 추진장치를 사용하는 소형무인항공기의 비행성능을 분석한다. 비행시험을 통해 얻은 데이터로부터 공력특성을 예측하고, 이를 활용하여 비행성능을 예측한다. 최대 항속시간을 얻을 수 있는 적정 비행속도를 제시하고, 비행속도에 따른 항속시간 및 항속거리를 예측한다.

• 한국수소및신에너지학회논문집
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• 제32권4호
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• pp.271-276
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• 2021

Although the development of electric vehicles or electric commercial vehicles is underway in Korea, most companies are seeking to enter the global market because it is difficult to expand their business only in the domestic market. In addition, it is recognized that the country has difficulties in responding to regulations or related procedures when entering overseas markets, and due to such difficulties, it is not possible to gain opportunities to enter the market and gain the technical advantage. Therefore, it is necessary to support individual companies to overcome the difficulties of promoting and exporting products by establishing a pre-cycle support environment for technology development so that development parts can be installed in small electric commercial vehicles. Therefore, this study tried to understand the necessity and factors of small electric commercial vehicles for major ASEAN countries, and as a result, most of them raised the urgency and necessity of joint research.In addition, human resource development, government support, and technical support were suggested as the necessary factors for the study.

• 한국기계가공학회지
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• 제20권1호
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• pp.116-124
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• 2021

In this study, the reliability of vehicle frames employed in small electric road sweepers was assessed through durability testing. The frames were tested under three conditions, whereby mechanical loads were applied to (1) the entire frame, (2) the front frame, and (3) the rear frame. The strain distributions in the loaded frames were determined through a combination of direct strain gauge measurements and supplementary numerical analysis. While subtle differences were observed between the experimental and numerical analyses, both methods successfully yielded comparable deformation patterns. Thus, the dependence of stress distribution and the state of the frame on loading conditions could be fully identified through our combined structural and numerical analysis.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.631-636
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• 2018

This paper proposed an optimal operation strategy for a hybrid energy storage system (HESS) with a lithium-ion battery and lead-acid battery for mild hybrid electric vehicles (mild HEVs). The proposed mild HEV system is targeted to mount the electric motor and the battery to a conventional internal combustion engine vehicle. Because the proposed mild HEV includes the motor and energy storage device of small capacity, the system focuses on low system cost and small size. To overcome these limitations, it is necessary to use a lead acid battery which is used for a vehicle. Thus, it is possible to use more energy using HESS with a lithium battery and a lead storage battery. The HESS, which combines the lithium-ion battery and the secondary battery in parallel, can achieve better performance by using the two types of energy storage systems with different characteristics. However, the system requires an operation strategy because accurate and selective control of the batteries for each situation is necessary. In this paper, an optimal operation strategy is proposed considering characteristics of each energy storage system, state-of-charge (SOC), bidirectional converters, the desired output power, and driving conditions in the mild HEV system. The performance of the proposed system is evaluated through several case studies with respect to energy capacity, SOC, battery characteristic, and system efficiency.

• 한국자동차공학회논문집
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• 제22권2호
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• pp.76-82
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• 2014

In this paper, an optimal power distribution algorithm is proposed for the small electric vehicle with front in-line and rear in-wheel motors. First, it is assumed that the vehicle driving torque and velocity are given conditions. And, an optimal problem is defined that finding the front and rear motor torques which minimizes the battery power. From the above optimization problem, the optimized front-rear motor torque distribution map is obtained. And, the vehicle simulations are performed to verify the performance of the optimal power distribution algorithm which is proposed in this study. The simulations are performed based on the federal urban driving schedule for two cases which are constant ratio power distribution, and optimal power distribution. From the simulation results, it is found that the optimal power distribution shows the 6.3% smaller battery energy consumption than the constant ratio power distribution.

• 한국추진공학회지
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• 제14권4호
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• pp.65-70
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• 2010

전기모터와 배터리로 구성된 추진장치를 사용하는 소형무인항공기는 무게가 8kg 이하로 손으로 던져 이륙이 가능하고 운용이 간편하면서도 실시간으로 영상정보를 전송할 수 있어 활용이 증가하고 있다. 하지만 이러한 소형무인항공기의 비행 성능에 대한 해석방법이나 해석결과는 별로 알려진 게 없다. 본 논문에서는 전기추진방식의 무인항공기 연구를 위해 제작한 소형무인항공기의 성능해석방법을 기술하고 결과를 도출한다. 비행체의 공력 데이터는 실제 비행시험으로부터 얻은 활공성능 데이터를 이용하여 구하고 비행속도에 따른 요구추력과 요구동력을 예측한다. 배터리를 동력원으로 사용하는 경우의 항속거리와 항속시간을 예측하는 방법을 제시하고 결과를 도출한다.

• 자동차안전학회지
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• 제15권3호
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• pp.27-33
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• 2023

Electric vehicles are widely produced from many car manufacturers around the world instead of internal combustion engine vehicle in order to respond a variety of environmental regulations. Also, they are applying for modular design method to develop plenty of the vehicles. And, both of these two issues will be an important trend to lead the future global automobile industries for a long time. In this paper, new brake architecture concept is proposed in order to respond to such a situation. First, physical interfaces between brake system like caliper, disc and other counter-parts are established for modular assembly. Second, we analyze effective factors of brake system for electric vehicles which need to reflect vehicle specifications such as total vehicle weight. Here, we consider ideal brake force by critical deceleration. Third, we simulate accumulated regenerative brake energy for two main driving modes to confirm to effectiveness for a variety of Electric Vehicle. Finally, we hope that it contributes to implement brake architecture for the development of Electric Vehicle platform through such a study.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.30-36
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• 2004

In this paper, operation algorithms for a parallel HEV equipped with a relatively small motor are investigated. For the HEV, the power assist and the equivalent fuel algorithms are proposed. In the power assist algorithm, an electric motor is used to assist the engine which provides the primary power source. Tn the equivalent fuel algorithm, the electric energy stored in the battery is considered to be an equivalent fuel, and an equivalent brake specific fuel consumption for the electric energy is proposed. From the equivalent fuel algorithm, distribution of the engine power and the motor power is determined to minimize the fuel consumption for a given battery state of charge (SOC) and a required vehicle power. It is found from the simulation results that the fuel economy and the final battery SOC depend on the motor discharge energy and it is the best way to charge the battery only by the regenerative braking, not by the engine to improve the overall fuel efficiency of the HEV with the relatively small motor.

• 전기학회논문지
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• 제64권12호
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• pp.1804-1809
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• 2015

The study in railway system to apply a fuel cell system with high efficiency and mobility than other renewable energy is being actively conducted. It is needed a analysis on load characteristics and control method of rolling stock in order to apply to rolling stock. This paper presents study on control small-scale prototype power converter electric railway vehicle using fuel cell generation system. Experiment is conducted through real fuel cell generation system and reference speed applying the driving curve of the actual electric railway vehicle was applied. Also, output voltage of boost converter is controlled considering characteristic of fuel cell. And it was confirmed characteristic according to powering and regeneration of inverter.

• 항공우주시스템공학회지
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• 제13권1호
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• pp.11-17
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• 2019

본 연구에서는 전기 동력 소형 고정익 무인항공기의 낮은 레이놀즈 영역 및 최소한의 제원으로 운용에 필요한 성능을 일반적인 이론 분석으로 예측하였다. 이를 간단한 전기모터 풍동시험과 실증 비행시험을 통해 비교 분석하여 이론 분석의 타당성을 확인하였다. 분석한 결과의 타당성 확인 결과, 3.5 kg의 고정익 소형 무인항공기는 일반적인 이론분석으로 공력 성능의 분석이 가능하지만, 필요추력은 설계오류가 발생할 가능성이 있는 것으로 확인된다. 이러한 연구 결과를 바탕으로 낮은 레이놀즈 영역에서 비행하는 유사 소형 고정익 무인항공기 개발 시 설계오류를 최소화 하는 방법을 제안하였다.