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Effective in-laboratory test method for PV power generation with enhanced PV emulation accuracy
Park, Seungbin,Kim, Mina,Jung, Jee-Hoon The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4
Photovoltaic (PV) systems require outdoor experiments to verify their functionality and reliability. However, outdoor experiments require complicated experimental set-ups including PV panels, power conversion circuits and controllers. In addition, the experimental data obtained from such systems can be easily affected by environmental conditions such as weather, temperature and season. Recently, PV emulation methods have been proposed that can emulate PV characteristics in the laboratory by connecting a DC supply to PV modules in parallel. However, the voltage characteristics of the conventional PV emulator are different from those of real PV panels, which degrades the accuracy of the PV emulator. This paper proposes an effective PV emulation method with accuracy improvements at the maximum power point of the PV panel, which is based on a simple circuit analysis. Using the proposed PV emulation method, the performance verification of a target PV system can be easily and accurately obtained. The proposed emulation method for PV power generation is experimentally verified by comparisons between it, the conventional emulation method and results obtained from outdoor experiments.
Seungbin Park,Mina Kim,Hoejeong Jeong,Katherine A. Kim,Taewon Kim,A-Rong Kim,Jee-Hoon Jung 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
A bidirectional flyback converter is a suitable topology for a PV-to-bus differential power processing (DPP) module in PV applications because of its electrical isolation capability, bidirectional power transfer, high step-up ratio, and simple circuit structure. Bidirectional flyback converters differ from the conventional flyback converters, which has power switches and snubber circuits on both the primary and secondary sides for bi-directional operations. The poor reverse recovery characteristics of the anti-parallel diode of the secondary (output) side power switch increase the switching loss and reduce the reliability. This paper proposes the design methodology of the bidirectional flyback converter for operating under the boundary conduction mode (BCM), which can show low power loss from the reverse recovery issue. The suitable magnetizing inductance is obtained by calculating the power losses in the bidirectional operation at the rated load. The validity of the proposed design methodology is verified using a 25.6-W bidirectional flyback converter prototype.
이승빈(Seungbin Lee),박수용(Sooyong Park),김의수(Euisoo Kim),박정배(Jeongbae Park) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.5
대기권에서 극초음속 비행체에 가해지는 공기역학적 가열로부터 비행체 내부의 시스템을 보호하기 위한 열관리 시스템 (Thermal Management System, 이하 TMS)의 개발은 극초음속 비행체를 위해 필요한 과정이다. 해외의 관련 기술연구 사례를 조사하여 열관리 시스템 개발의 동향을 파악하였다. Development of a thermal management system (TMS) to protect the system inside the vehicle from aerodynamic heating applied to the hypersonic vehicle in the atmosphere is a necessary process for the hypersonic vehicle. The trend of development was identified by examining cases of related technology research abroad.
맞대기 이음 용접의 피로수명에 베벨 각도가 미치는 역할
박지환(Jihwan Park),한창완(Changwan Han),정승빈(Seungbin Jung),박성훈(Seonghun Park) 한국자동차공학회 2014 한국 자동차공학회논문집 Vol.22 No.2
This study aims to investigate the influence of bevel angles on the fatigue life of V-groove butt-welded joints with back-plates made by SM490A steel material, generally used for excavators, because changes in the geometry, material and surface properties of welded regions affect the fatigue life of welded structures. Butt type test specimens were prepared by the CO₂ welding of rolled steel plates (SM50A steel) with a thickness of 13.5 mm at a welding speed of 30 cm/min and these Butt type test specimens had two different groove angles, which are 40° (A type) and 30° (B type). In order to investigate differences in fatigue life between two types, 4-point bending fatigue tests were conducted with a stress ratio of R=0.1 under the cyclic loading environment at a frequency of 5 Hz at room temperature. The fatigue life of A type specimens was approximately 7% higher than that of B type specimens. The stress concentration factors calculated by finite element analysis were 2.16 for A type and 2.25 for B type, whose difference was caused by the influence of the back-plates of butt-welded structures. The current results could provide important guidelines to determine the V-groove angle of butt-welded joints with a satisfactory fatigue life, although under severe operating conditions.
Practical bending-angle calculation for an automated surgical plate bending apparatus
Si-Myung Park,Jeonghwan Lee,Seungbin Park,Jung-Woo Lee,박민수,김영준,노건우 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.5
Surgical plates used for reconstructive surgery require a repetitive manual bending process to fit the plate to the defect during reconstruction. However, this process may not produce a plate that fits well, and repetitive bending may significantly increase the risk of plate fracture due to the accumulation of residual stress. In this study, the input angle is calculated using a proposed finite element process that considers the spring-back effect and improves the accuracy of the bending results without the need for repetitive bending. Bending tests for two arbitrary target angles (15° and 30°) are performed using the apparatus to demonstrate its effectiveness. Accurately bent plates are obtained from a single bending trial, unlike the use of another input angle that does not consider spring-back. Therefore, the proposed bending procedure could potentially replace the repetitive manual bending process and reduce the residual stress within the plate, thus lowering the risk of plate failure.