엔진입구 공기유동의 전압력/전온도 측정을 위한 레이크의 회복률 평가

이보화(Bohwa Lee),이경재(Kyungjae Lee),이양지(Yang Ji Lee),양인영(Inyoung Yang),김춘택(Chuntaek Kim) 한국항공우주학회 2016 한국항공우주학회 학술발표회 논문집 Vol.2016 No.11

Comparison Study on Power Output Characteristics of Power Management Methods for a Hybrid-electric UAV with Solar Cell/Fuel Cell/Battery

Bohwa Lee,Sejin Kwon 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.4

A dual-mode power management for a hybrid-electric UAV with a cruise power of 200W is proposed and empirically verified. The subject vehicle is a low-speed long-endurance UAV powered by a solar cell, a fuel cell, and a battery pack, which operate in the same voltage bounds. These power sources of different operational characteristics can be managed in two different methods: passive management and active management. This study proposes a new power management system named PMS2, which employs a bypass circuit to control the individual power sources. The PMS2 normally operates in active mode, and the bypass circuit converts the system into passive mode when necessary. The output characteristics of the hybrid system with the PMS2 are investigated under simulated failures in the power sources and the conversion of the power management methods. The investigation also provides quantitative comparisons of efficiencies of the system under the two distinct power management modes. In the case of the solar cell, the efficiency difference between the active and the passive management is shown to be 0.34% when the SOC of the battery is between 25~65%. However, if the SOC is out of this given range, i.e. when the SOC is at 90%, using active management displays an improved efficiency of 6.9%. In the case of the fuel cell, the efficiency of 55% is shown for both active and passive managements, indicating negligible differences.

Comparison Study on Power Output Characteristics of Power Management Methods for a Hybrid-electric UAV with Solar Cell/Fuel Cell/Battery

Lee, Bohwa,Kwon, Sejin The Korean Society for Aeronautical and Space Scie 2016 International Journal of Aeronautical and Space Sc Vol.17 No.4

A dual-mode power management for a hybrid-electric UAV with a cruise power of 200W is proposed and empirically verified. The subject vehicle is a low-speed long-endurance UAV powered by a solar cell, a fuel cell, and a battery pack, which operate in the same voltage bounds. These power sources of different operational characteristics can be managed in two different methods: passive management and active management. This study proposes a new power management system named PMS2, which employs a bypass circuit to control the individual power sources. The PMS2 normally operates in active mode, and the bypass circuit converts the system into passive mode when necessary. The output characteristics of the hybrid system with the PMS2 are investigated under simulated failures in the power sources and the conversion of the power management methods. The investigation also provides quantitative comparisons of efficiencies of the system under the two distinct power management modes. In the case of the solar cell, the efficiency difference between the active and the passive management is shown to be 0.34% when the SOC of the battery is between 25-65%. However, if the SOC is out of this given range, i.e. when the SOC is at 90%, using active management displays an improved efficiency of 6.9%. In the case of the fuel cell, the efficiency of 55% is shown for both active and passive managements, indicating negligible differences.

Active power management system for an unmanned aerial vehicle powered by solar cells, a fuel cell, and batteries

Bohwa Lee,Sejin Kwon,Park, Poomin,Kim, Keunbae IEEE 2014 IEEE transactions on aerospace and electronic syst Vol.50 No.4

<P>200W class, low-speed, long-endurance unmanned aerial vehicle (UAV) that employs solar cells, a fuel cell, and a battery pack as its power sources is considered. This study applies an active power management method that directs each individual source to generate the appropriate power, depending on the power supply and demand, instead of the passive method in which the power sources irresponsibly generate power, depending on their characteristics. The power management system (PMS) under active management determines the power output from each source. The flight test of the UAV with a PMS onboard is conducted for 3.8 h. The active PMS verifies its own feasibility as it successfully keeps the power sources within their proper operational bounds and maintains a target state-of-charge of 45%, while responding to the various conditions associated with the power required. In addition, through a comparison of flight test results with a power simulation of the passive method, the usefulness, advantages, and disadvantages of an active power management method over a passive method are investigated.</P>

고공환경시험설비에서 사용 중인 레이크의 전압력 회복률 평가

이보화(Bohwa Lee),김춘택(Chuntack Kim) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12

엔진고공환경시험설비는 공기유량을 계산하기 위해 엔진입구덕트에 장착된 전압력/전온도 레이크를 통해 측정된 전온도와 전압력값으로부터 계산된다. 본 연구에서는 전압력 측정용 레이크에 대하여 PLA의 변화에 따른 전압력 회복률을 평가하였다. 상용 CFD 툴인 ANSYS Fluent를 사용하였으며 해석 결과 마하수 0.7, 고도 18,000ft, 표준대기조건에서 평균 0.97로 평가되었다. In Altitude Engine Test Facility, airflow is calculated using measured data that are total temperatures and total pressures through engine inlet duct mounted rakes. This study is performed to evaluate total pressure recovery according to PLA variation about total pressure rakes. ANSYS Fluent is used for CFD analysis, it is revealed that the results are average 0.97 at Sea Level/Mach number 0.7/ 18,000ft condition.

능동전력제어에 의한 하이브리드 동력시스템의 출력특성 연구

이보화(Bohwa Lee),박부민(Poomin Park) 한국항공우주학회 2016 韓國航空宇宙學會誌 Vol.44 No.9

본 연구에서 대상으로 삼은 순항 200 W급 전기동력무인기는 태양전지, 연료전지, 배터리를 동시에 주 전력원으로 사용한다. 각 전력원별 출력은 능동전력제어 방식에 의해 연료전지의 최대 출력을 제한한 상태에서 배터리의 적정용량을 유지하도록 각 전력원별 전력제어를 수행하게 된다. 능동전력제어 방식에 의한 각 전력원별 출력변동은 지상통합시험을 통해 확인하였다. 또한 연료전지의 최대출력제한이 전체 시스템의 출력변동에 미치는 영향을 실험적으로 확인하였으며, 연료전지의 최대출력값은 연료전지 시스템용 6직렬 소형 배터리의 과방전을 방지하기 위해서는 150W가 적절함을 확인하였다. The 200 W electrically powered unmanned aerial vehicle, which is studied in this research, uses solar cells, a fuel cell and batteries as the main power source simultaneously. The output of each power source performs power control for each power source by the active power control method so that an adequate capacity of the battery could be maintained while limiting the maximum output of the fuel cell. The output variation for each power source under the active power control method was identified through an integrated ground test. In addition, the effect of limiting the maximum output of the fuel cell on the output variation of the entire system was experimentally identified, and it was confirmed that the adequate maximum output value of the fuel cell for preventing the overdischarge of six series-connected, small size batteries for fuel cell systems is 150 W.

드론용 하이브리드 동력시스템 모델링 및 비행성능 시뮬레이션

이보화(Bohwa Lee),김근배(Keunbae Kim) 한국항공우주학회 2022 한국항공우주학회 학술발표회 논문집 Vol.2022 No.11

하이브리드 전기추진 시스템 지상통합시험

이보화(Bohwa Lee),김영문(Youngmun Kim),박부민(Poomin Park),김근배(Keunbae Kim),차봉준(Bongjun Cha) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11

개발 중인 중형 전기추진 무인기는 전력원으로 태양전지, 연료전지, 이차전지를 사용한다. 전력변환기 및 컨버터를 없이 전압 매칭을 통해 전력원을 선정하고 단품시험을 수행하였다. 여러 종류의 전력원을 통합하여 사용함에 따른 각 전력원 별 특성파악 및 에너지 사용 비율을 정량적으로 평가하기 위해 5시간 지상통합시험을 수행하였다. 그 결과 배터리는 시동 및 과도상태에서 다른 동력원에 비해 빠른 출력반응을 보였으며, 연료전지와 태양전지는 순항영역에서 주 전력 공급원의 역할을 수행함을 확인하였다. 사용한 에너지 비율은 연료전지, 태양전지, 배터리가 각각 68%, 29%, 2.5%임을 알 수 있었다. EAV-2, which has a solar cell, fuel cell and battery as its power sources, is under development by KARI. Electric power sources are selected through voltage matching without power converter and controller and tested. The ground integrated test for integrated system is performed during 5 hr. it is confirmed that battery‘s power response is faster than other power sources at starting and transient condition, fuel cell and solar cell are a major electrical power during cruise condition. It is revealed that the used energy portions of fuel cell, solar cell and battery are 68%, 29%, 2.5% respectively.

습도 영향을 고려한 초소형 터보제트 엔진 성능시험 소개

이보화(BoHwa Lee),이경재(KyungJae Lee),양수석(SooSeok Yang),김유일(Yuil Kim) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.11

대기 중의 수증기는 가스터빈엔진의 주요성능에 많은 영향을 끼친다. 습공기의 영향은 기온 및 기압이 높은 여름철 해면 고도, 높은 비행 마하수 그리고 낮은 엔진 회전수에서 그 영향이 더욱 두드러진다. 이러한 습공기 유입에 따른 가스터빈 엔진의 성능변화의 정도를 살펴보고자 200lbf 급 초소형 터보제트 엔진의 고공환경 성능시험을 통해 습도가 엔진성능에 미치는 영향에 대하여 알아보았다. 고공환경 엔진시험을 통해, 건공기 유입에 비해 습공기 유입 시 순추력에서 2.826% 낮게, 비연료소모율에서 1.325% 높게 측정되었다. The moisture in the atmosphere exerts a lot of influence upon Gas turbine engine performances. There is a noticeable influence of wet air at the summer sea level, high flight mach number and low engine rpm increasingly. An altitude Engine Test Facility is used to accomplish the engine performance tests at dry air condition and wet air condition, through which engine performance results is revealed. In the result, net thrust and specific fuel consumption measured -2.826% and 1.325%, respectively at wet air condition compared to dry air condition.

습도가 엔진성능에 미치는 영향에 대한 실험적 고찰

이보화(BoHwa Lee),이경재(KyungJae Lee),양수석(SooSeok Yang),김춘택(ChunTaek Kim) 한국항공우주연구원 2010 항공우주기술 Vol.9 No.2

대기 중의 수증기는 가스터빈엔진의 주요성능에 많은 영향을 끼친다. 습공기의 영향은 기온 및 기압이 높은 여름철 해면 고도, 높은 비행 마하수 그리고 낮은 엔진 회전수에서 이 더욱 두드러진다. 이러한 습공기 유입에 따른 가스터빈 엔진의 성능변화의 정도를 살펴보고자 가스터빈 시뮬레이션 프로그램(GSP)과 200lbf 급 초소형 터보제트 엔진의 고공환경 성능시험을 통해 습도가 엔진성능에 미치는 영향에 대하여 알아보았다. 고공환경 엔진시험을 통해, 건공기 유입에 비해 습공기 유입 시 순추력에서 2.826% 낮게, 비연료소모율에서 1.325% 높게 측정되었다. The moisture in the atmosphere exerts a lot of influence upon Gas turbine engine performances. There is a noticeable influence of wet air at the summer sea level, high flight mach number and low engine rpm increasingly. An altitude Engine Test Facility is used to accomplish the engine performance tests at dry air condition and wet air condition, through which engine performance results is revealed. Also, Gas turbine Simulation Program is used to predict the variation of engine performance due to inlet humidity. In the result, net thrust and specific fuel consumption measured -2.826% and 1.325%, respectively at wet air condition compared to dry air condition.