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전자비례감압밸브를 사용한 폐회로 선회독립시스템의 마력제어
박형준(H. J. Park),안현식(H. S. Ahn),홍기환(K. H. Hong),장윤석(Y. S. Jang) 유공압건설기계학회 2013 유공압건설기계학회 학술대회논문집 Vol.2013 No.10
The hydraulic system of construction machinery such as negative flow control makes pressure loss of the pump as because it operates many actuators, and the velocity of actuators is decreased because hydraulic is distributed to each actuator in a complex movement. To solve these problems, hydraulic system able to use swing motion independently by installing pump only for swing motor is being developed. But, independent swing system has to control engine power in a complex movement as swing pump is added to it. Also, it needs power control to improve operation performance in a complex movement. Therefore, the method of power control for independent swing system using electro-proportional pressure reducing valve is proposed in this paper.
송인호(I.H. Song),안현식(H.S. Ahn),박기원(K.W. Park),장계용(G.Y. Jang),신현석(H.S Shin),이용운(Y.W. Lee),최창호(C.H. Choi),조무현(M.H. Cho) 전력전자학회 2006 전력전자학술대회 논문집 Vol.- No.-
KSTAR (Korea Superconducting Tokamak Advanced Research) 장치는 Tokamak 개념의 핵융합 연구 장치로서 플라즈마를 가두기 위한 자장을 발생하는 토로이달 자장 (Toroidal Field, TF) 코일과 플라즈마 발생 및 형상 조정을 위한 폴로이달 자장 (Poloidal Filed, PF) 코일로 구성되며, 초전도 코일을 이용한다. TF 코일의 전원장치로는 40kA급의 안정 된 직류 전원장치가 필요하며, PF 코일의 전원장치로는 빠른 전류상승 및 피드백 기능을 갖춘 정밀 대전류 전원을 필요로 한다. 또한 초전도 코일의 퀜치현상 발생 시 코일과 전원장치 보호를 위한 대전류 직류 차단시스템을 필요로 한다. KSTAR 장치의 설계에 의하면 상하 7쌍의 초전도 PF 코일에 약 1 MA/sec급의 고속 전류구동을 운전 시나리오에 따라 인가하여 핵융합 연구를 위한 플라즈마를 생성한다. 본 논문은 TF 및 PF 코일에 대전류를 인가하기 위해서 개발된 전원장치 (Power Supply, PS)에 관한 연구이다.
DEVELOPMENT OF THE FLOW AREA OPTIMIZATION FOR A HYDRAULIC EXCAVATOR
K.Y. Kim(김기용),Y.S. Jang(장윤석),H.S. Ahn(안현식) 유공압건설기계학회 2015 유공압건설기계학회 학술대회논문집 Vol.2015 No.6
This paper describes how to find optimized combination of maximum flow area of bucket spool’s meter-in, meter-out, and regen, which is related to maximum speed of excavator’s bucket and pump pressure. This optimized combination of flow area could improve fuel efficiency. First, an excavator front parts (boom/arm/bucket) and hydraulic system related to bucket motion, were modeled using AMESim software. This simulation model was tuned to match real excavator’s pressure/flow profile using several ‘black box’ orifices which are simple and which we don’t need to make complicated model consists of orifices, valves, pipes, and hoses. This tuning was automatically accomplished by genetic algorithm. An objective function of this tuning is to minimize root mean square errors between simulation data and experimental data in terms of bucket cylinder’s velocities and pump pressures. After this, the flow area of bucket spool’s meter-in, meter-out, and regen was optimized by genetic algorithm again. An objective function of this optimization is to minimize pump pressure under constraints which satisfies proper bucket cylinder velocity. After applying the best result from the optimization, fuel efficiency in terms of bucket single motion was improved as much as pump pressure decrease because pump flow quantity, which is proportional to bucket cylinder velocity, is almost same as before.
직동형 릴리프밸브의 오버라이드 저감을 위한 포펫 형상 설계요소 연구
김성원(S. W. Kim),서영민(Y. M. Seo),안현식(H. S. Ahn) 유공압건설기계학회 2015 유공압건설기계학회 학술대회논문집 Vol.2015 No.6
A direct acting relief valve, of which the override is one of the important issues, is major hydraulic element for controlling pressure and flow in hydraulic actuating systems. Therefore, the research of reducing override of the valve has always been an important topic for decades. Among many design factors of the direct acting relief valve, the shape of the valve poppet is the one that can directly affect the performance the most. Based on previous studies of poppet valve, an actual model is considered as equivalent to the simplified model. The steady flow force acting on the poppet is calculated by momentum theorem applied to the control volume. This paper represents some simulation methods to investigate the flow force effects depending on the shape of the poppet with sharp-edged seat. The result shows that the flow force on poppet is highly affected by inlet/outlet opening areas, poppet tip angle, and poppet plate angle.
3kW급 계통연계형 태양광 발전시스템의 성능 비교 분석
소정훈(J.H. So),정영석(Y.S. Jung),유권종(G.J. Yu),이기옥(K.O. Lee),최주엽(J.Y. Choi),안현식(H.S. Ahn) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.7(2)
3kW grid-connected photovoltaic (PV) system and data acquisition system are constructed for performance analysis of PV system at field demonstration test center of Gwang- Ju in Korea. As climatic and irradiation conditions are varied, operation characteristics of the PV system are collected and analyzed in data acquisition system. From these results, the performances of PV system have simulated and evaluated using simulation tool in comparison with actual value of data acquisition system of field demonstration test center. Furthermore, performance of total PV system ego electric power and loss factor at the site are reviewed.<br/>
김기용(K. Y. Kim),장달식(D. S. Jang),안현식(H. S. Ahn) 유공압건설기계학회 2008 드라이브·컨트롤 Vol.5 No.4
For the bucket tip position control of the excavator, a traditional hydraulic excavator system was exchanged into an electro-hydraulic one. EPPR valves are attached to the traditional Mev and hydraulic joysticks are replaced by electronic ones to develop the electro-hydraulic system. To control the electronic pump with a good performance, the control logic for the pump is deduced from the AMESim simulation and the experimental method on the test bench. To get a good position control performance of the excavator bucket tip, PI+AntiWindup controller is selected as a position controller. The experimental results showed the good controllability for the electro-hydraulic excavator system on the test bench.