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전기굴삭기 에너지 효율 향상을 위한 유압펌프 - 전동기 통합 제어 알고리즘
이지호(Jeeho Lee),이지혜(Jihye Lee),이형철(Hyeongcheol Lee),오창은(Chang Eun Oh) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.2
전기굴삭기는 배터리에 저장된 에너지로 전동기-유압펌프를 구동해서 유압 에너지를 생성하고 이를 작업에 활용한다. 기존 유압굴삭기의 유압펌프는 디젤 엔진의 운전 효율에 최적화된 레귤레이터에 의해 제어되고, 유압펌프 자체의 효율은 고려되지 않았다. 전기굴삭기는 배터리를 에너지원으로 사용하기 때문에 전동기의 효율뿐 아니라 유압펌프의 효율을 함께 고려한 제어가 요구된다. 통합 제어를 위해서 유압펌프와 전동기의 출력과 효율 특성을 분석하여 효율맵을 작성하였고, 이를 바탕으로 최적동작맵을 구성하고 통합 제어 알고리즘을 개발했다. 알고리즘의 효과를 확인하기 위해 전기굴삭기 MILS 를 구성해서 통합 제어 알고리즘을 적용했다. 굴삭기 작업 시뮬레이션 결과는 통합 제어 알고리즘이 시스템 효율을 향상 시켰음을 보여준다. An electric excavator consumes battery energy to drive an electric motor attached to a hydraulic pump to generate hydraulic power. In a conventional hydraulic excavator, the hydraulic pump is controlled by regulators, which are used to optimize the diesel engine efficiency. Because of a lack of battery energy capacity, an electric excavator controller should consider not only the electric motor efficiency but also the hydraulic pump efficiency. Thus, electric motor and hydraulic pump efficiency maps were constructed. An optimal operating map (OOM) was created based on the most efficient operating points under each input condition. An integrated control algorithm controlled the speed of the electric motor and displacement of the hydraulic pump according to the OOM. To confirm the utility of this algorithm, a model-in-the-loop simulator for the algorithm with an electric excavator was established. The simulation results showed that the integrated control algorithm improved the energy efficiency of an electric excavator.
전기굴삭기 효율향상을 위한 전기동력시스템 동작점 제어알고리즘 연구
이지호(Jeeho Lee),이형철(Hyeongcheol Lee),염준형(Joonhyung Yeom),이상훈(Sanghoon Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
The working time of electric excavator needs to be extended by improving efficiency of the electric power system. In this paper, the characteristics and efficiency maps of tandem pump-electric motor system is analyzed and the control algorithm which optimize the displacements of the tandem pump is established. To confirm the utility of this algorithm, the model-in-the-loop simulator of electric excavator for the algorithm is established. The simulation results shows that the control algorithm improved the energy efficiency of the electric excavator.
듀얼 모드 하이브리드 시스템 기반의 플러그인 하이브리드 굴삭기 모델링 및 성능해석
이상민(Sangmin Lee),이지호(Jeeho Lee),이상훈(Sang Hoon Lee),이형철(Hyeongcheol Lee) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
A Plug-In Hybrid Excavator is composed of an electric motor to drive a hydraulic pump, a battery to generate electrical energy and an auxiliary engine/generator to charge a battery. It is designed to work by consuming the electrical energy of a battery. In this system, when the battery SOC drops below a certain range, a auxiliary engine/generator charges the battery. In the case of Series Hybrid system, there is a disadvantage that the energy conversion loss is relatively large. To overcome the disadvantage, the power distribution mechanism by using the Dual-Mode Hybrid system is proposed in this paper. The Dual-Mode Hybrid system operates in two modes: input split mode and compound split mode. The former has an advantage in a low workload range while the latter has an advantage in a high workload range. In this paper, the Series Hybrid system and the Dual-Mode Hybrid system are modeled and the simulation is conducted to verify the feasibility of the power distribution mechanism. The simulation results show that the performance by the Dual-Mode Hybrid system is improved compared with a series type plug-in hybrid excavator.
A two-level parallel algorithm for material nonlinearity problems
Lee, Jeeho,Kim, Min Seok Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.4
An efficient two-level domain decomposition parallel algorithm is suggested to solve large-DOF structural problems with nonlinear material models generating unsymmetric tangent matrices, such as a group of plastic-damage material models. The parallel version of the stabilized bi-conjugate gradient method is developed to solve unsymmetric coarse problems iteratively. In the present approach the coarse DOF system is solved parallelly on each processor rather than the whole system equation to minimize the data communication between processors, which is appropriate to maintain the computing performance on a non-supercomputer level cluster system. The performance test results show that the suggested algorithm provides scalability on computing performance and an efficient approach to solve large-DOF nonlinear structural problems on a cluster system.
Return-Mapping Algorithm for Cyclic Loading Analysis of Damaged Structures
Jeeho LEE 한국산업응용수학회 2005 한국산업응용수학회 학술대회 논문집 Vol.- No.-
In this paper new return-mapping algorithm for the continuum large crack model is proposed for analysis of damaged structures subjected to cyclic loading. The algorithm consists of one elastic predictor and two return-mapping correctors. The numerical test results show that the present algorithm works appropriately under cyclic loading and should be used in large crack problems to prevent excessive tensile plastic strain causing unrealistic results.
HIL Simulation Approach for Feasibility Study of a Tram with an Onboard Hybrid Energy Storage System
Jeeho Lee,Namju Jeon,Hyeongcheol Lee 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
A hardware-in-the-loop (HIL) simulator was designed and fabricated for feasibility study of the tram with onboard hybrid energy storage system comprising the Li battery and the ultra-capacitor. HIL simulator consists of the software part including the vehicle model, the energy storage system model, and control algorithm; and the hardware testbench containing a induction motor for the load, a permanent magnet synchronous motor to emulate the traction motor, and the electric drivers. The vehicle model of the HIL simulation system was validated with the test results. A power distribution algorithm is proposed to control the hybrid energy storage system to increase the capacity and the peak current. The Simulation results show that the hybrid energy storage system for the tram gives better efficient power and durability compared with the battery alone system.
Spin Axis Determination of Defunct GLONASS Satellites Using Photometry Observation
Jeeho Lee,Eunseo Park,Man-Soo Choi,Daniel Kucharski,Yu Yi,Jong-Uk Park 한국우주과학회 2021 Journal of Astronomy and Space Sciences Vol.38 No.1
GLONASS, a satellite navigation system developed in Russia since 1976, is defunct and orbits in an unstable attitude. The satellites in these problems are not managed and there is no precise information, which can increase the risk of collisions with other space objects. In this study, detailed attitude dynamic have to be analyzed through photometry data, which requires spin period and spin axis. The light curve data is obtained by observing through the photometer at the Graz station and the power spectrum is calculated to obtain the cycle of the satellite. The geometric relationship between observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to obtain the phase reflection of the satellite and obtain the Irradiation of the satellite through this information. In Light Curve and Irradiation, the spin axis is calculated for each peak points with the distance square minimum technique. The spin axis of the GLONASS-50 satellite is RA = 116°, Dec = 92°.
A study for improvement performance of electric brake for electric train
JeeHo Lee,Hyeongcheol Lee,Jaeho Kwak 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Recently electric brake system is noticed in electric railroad because of its nice speed controllability, environment friendly, energy saving, good maintainability. The electric brake means regenerative brake is activate when the motor operates as generator. And then kinetic energy converted to electrical energy. In electric railroad, Vehicle’"s traction system changed to VVV inverter and vehicles came be able to regenerative brake. But there are several problems with it like it’"s regeneration failure uncontrollable at low speed This paper find regenerative brake’"s merits contract to mechanical brake and problems. And then how to make up for the problems.
Spin Axis Determination of Defunct GLONASS Satellites Using Photometry Observation
Lee, Jeeho,Park, Eunseo,Choi, Man-Soo,Kucharski, Daniel,Yi, Yu,Park, Jong-Uk The Korean Space Science Society 2021 Journal of astronomy and space sciences Vol.38 No.1
GLONASS, a satellite navigation system developed in Russia since 1976, is defunct and orbits in an unstable attitude. The satellites in these problems are not managed and there is no precise information, which can increase the risk of collisions with other space objects. In this study, detailed attitude dynamic have to be analyzed through photometry data, which requires spin period and spin axis. The light curve data is obtained by observing through the photometer at the Graz station and the power spectrum is calculated to obtain the cycle of the satellite. The geometric relationship between observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to obtain the phase reflection of the satellite and obtain the Irradiation of the satellite through this information. In Light Curve and Irradiation, the spin axis is calculated for each peak points with the distance square minimum technique. The spin axis of the GLONASS-50 satellite is RA = 116°, Dec = 92°.