• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.456-465
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• 2019

PHEV(Plug in Hybrid Electric Vehicle) and BEV(Battery Electric Vehicle) equip high voltage batteries to drive motor and vehicle electric system. Those vehicle require OBC(On-Board Charger) for charging batteries and LDC(Low DC/DC Converter) for converting from high voltage to low voltage. Since the charger and the converter actually separate each other in electrical vehicles, there is a margin to reduce the vehicle weight and area of installation by integration two systems. This paper studies a 1.5kW LDC converter that can be integrated into an OBC using an isolated current-fed converter by simplifying the design of LDC transformers. The proposed LDC can control the final output voltage of the LDC by using a fixed arbitrary output voltage of the bidirectional buck-boost converter, so that Compared to the existing OBC-LDC integrated system, it has the advantage of simplifying the transformer design considering the battery voltage range, converter duty ratio and OBC output turn ratio. Prototype of the proposed LDC was made to confirm normal operation at 200V ~ 400V input voltage and maximum efficiency of 91.885% was achieved at rated load condition. In addition, the OBC-LDC integrated system achieved a volume of about 6.51L and reduced the space by 15.6% compared to the existing independent system.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.21-28
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• 2020

Integrated bidirectional OBC/LDC was developed to reduce the volume for elements, avoid space restriction, and increase efficiency in EV vehicles. In this study, a DC-DC converter in integrated OBC/LDC circuits was composed of an SRC circuit with a stable output voltage relative to an LLC circuit using a theoretical method and simulation. The resonant network of the selected circuit was optimized to minimize the power loss and element volume under constraints for the buck converter and the battery charging range. Moreover, the validity of the optimal model was verified through an analysis using a theoretical method and a numerical analysis based on power loss at the optimized resonant frequency.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.401-402
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• 2020

본 논문에서는 차량 탑재형 충전기 (OBC)와 저 전압 배터리 충전기 (LDC)의 각 기능에 대해 분석한다. 또한, 두 배터리 충전기를 통합한 OBC-LDC 통합형 회로의 장·단점과 기능에 대해 분석한다. 또한, OBC-LDC 통합형 회로에 대한 두 토폴로지의 장·단점을 비교 분석하고, PSIM을 사용하여 각 토폴로지에 대한 시뮬레이션을 진행하여 회로의 동작 및 성능을 비교 분석한다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.94-96
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• 2020

본 논문은 전 범위 ZVS를 가지는 OBC-LDC 통합형 차량용 충전기를 제안한다. 제안하는 통합형 충전기는 OBC의 절연부인 양방향 LLC 공진형 컨버터의 2차측 스위치 레그와 LDC의 위상천이 풀브릿지 컨버터의 lagging 레그를 공통으로 사용하여 스위치 개수를 2개 줄일 뿐아니라 경부하에서 ZVS 성취가 어려운 lagging 레그의 전 범위 ZVS 턴온을 가능케 한다. 제안하는 통합형 충전기는 OBC와 LDC의 동시동작이 가능하며 OBC와 LDC가 같이 동작할 때 전류 상쇄효과로 인해 도통손실을 저감할 수 있다. 또한 OBC와 LDC가 동일주파수로 동작하므로 고전압측 출력필터와 EMI 필터의 설계가 간단해지는 장점이 있다. 3.6kW급 LLC 공진형 컨버터와 1kW급 위상천이 풀브릿지 컨버터로 구성되는 통합형 충전기의 시작품을 제작하여 본 논문의 타당성을 증명하였다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.13-14
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• 2016

This paper has introduces a novel Integrated On-board Charger (IOBC) to reduce the size, weight and cost of power conversion stages in Electric Vehicles (EVs). The IOBC is composed of an OBC and a low voltage dc-dc converter (LDC). The IOBC includes a bidirectional ac-dc converter and a bidirectional full-bridge converter with an active clamp circuit. The LDC converter is a hybrid topology combining an active clamped full-bridge converter and a forward converter derived from the Weinburg converter topology. Unlike conventional OBC, the proposed IOBC is compact and the LDC converter of it can achieve a higher efficiency. In addition, the LDC converter of the proposed IOBC can achieve high step-down voltage conversion ratio, no circulating current, no reverse recovery current of the rectifier diodes and small ripple current of output inductor on the auxiliary battery. A 1kW hardware of the LDC converter is implemented to verify the performances of the proposed IOBC.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.728-737
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• 2019

In this study, the minimized on-board computer (OBC) module for integrated navigation is developed, which provides satellites' relative position information in formation flying and cluster operation situations. The scalability is considered to apply the user-selected wireless communication module and Global Positioning System (GPS) receiver for navigation, while considering to meet the structural design standard of nano-satellites. As a result of the product development and production, the processing speed of integrated navigation and real-time data synchronization is satisfied for cluster operation nano-satellites by using micro controller unit (MCU). From a heat/vacuum, vibration and radiation test, the OBC was confirmed to be operated in space environments. From these results, a mass production system of OBC was made which is a key part of development on satellite formation flying and cluster/constellation missions that the community demands are increasing.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1212-1218
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• 2014

For OBC (On-Board Charger) and LDC (Low DC-DC Converter) used as essential power conversion systems of PHEV (Plug-in Hybrid Electric Vehicle), system performance is required as well as reliability, which is need to protect the vehicle and driver from various faults. While current development processor is sufficient for embodying functions and verifying performance in normal state during development of prototypes for OBC and LDC, there is no clear method of verification for various fault situations that occur in abnormal state and for securing stability of vehicle base, unless verification is performed by mounting on an actual vehicle. In this paper, a CCM (Charger Converter Module) was developed as an integrated structure of OBC and LDC. In addition, diverse fault situations that can occur in vehicles are simulated by a simulator to artificially inject into power conversion system and to test whether it operates properly. Also, HILS (Hardware-in-the-Loop Simulation) is carried out to verify whether LDC is operated properly under power environment of an actual vehicle.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.109-115
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• 2008

It is very important to estimate the physical properties of survey area and delineate the geological basement in marine site survey for the design of offshore structures. For the purpose of providing high quality data by means of engineering site survey, it is necessary to apply several survey techniques and carry out the integrated interpretation to each other. In this study, we applied single channel seismic reflection method and OBC (Ocean Bottom Cable) type seismic refraction method at shallow marine. We used a dual boomer-single channel streamer as a source-receiver in seismic reflection survey and airgun source-the developed OBC type streamer in seismic refraction survey. We made 24 channels OBC type streamer which has 4m channel interval and each channel is composed of single hydrophone and preamplifier. We tested the field applicability of the proposed method and applied the typical seismic data processing methods to the obtained reflection data in order to enhance the data quality and image resolution. In order to estimate the geological velocity distribution from refraction data, seismic refraction tomography technique was applied. Therefore, we could successfully perform time-depth conversion using the velocity information as an integrated interpretation. The proposed method could provide reliable geologic information such as sediment layer thickness and 3D basement depth map.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.239-240
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• 2011

본 논문에서는 도심형 근거리 전기자동차의 구동을 위한 통합형 전력변환장치 개발에 대해 소개한다. 차량 구동용 유도 전동기 제어와 주동력 배터리 충전 및 전장배터리 충전의 기능을 가지기 위하여 MCU(Motor Control Unit), OBC(On-Board Charger), LDC(Low Voltage DC-DC Converter)를 적용하였다. 각각의 전력변환장치들 사이에 불필요한 커넥터를 없애고 단일 방열판 위에 각 요소부품을 배치하여 하나의 통합된 기구 물 위에 모든 기능을 발휘하도록 통합형 전력변환장치를 개발하였다. 개별 기능을 가지는 MCU와 OBC, LDC의 단품 성능시험을 거친 후 실차에 장착하여 차량모터제어 및 배터리 충전을 실험을 통하여 확인하였다.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.349-352
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• 2007

Estimating the physical properties of the survey area and mapping the geotechnical basement play an important role in ocean engineering and construction field. In this study, we performed marine seismic reflection and refraction survey as an engineering application at shallow marine. We made use of the dual boomer - single channel streamer as a source-receiver in reflection seismic survey and air-gun source - the manufactured OBC(Ocean Bottom Cable)-type streamer in refraction survey. In the seismic reflection data, we could easily find the geological layers and basement. Moreover, seismic refraction data could present sediment thickness and velocity distribution.