• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.66-67
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• 2014

Stabilization of the DC bus voltage is an important task in DC-AC microgrid system with renewable energy source such as solar system. A battery energy storage system (BESS) has become a general solution to stabilize the DC-bus voltage in DC-AC microgrid. This paper develops the analog BESS controller which requires neither computation nor dc-bus voltage measurement, so that the system can be implemented simply and easily. Even though others methods can stabilize and control the DC-bus voltage, it has complicated structure in control and low adaptive capability. The proposed topology is simple but is able to compensate the solar source variation and stabilize the DC-bus voltage under any loads and distributed generation (DG) conditions. In addition, the design of analog controller is presented to obtain a robust system. In order to verify the effectiveness of the proposed control strategy, simulation is carried out by using PSIM software.

• 전력전자학회논문지
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• 제23권1호
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• pp.1-8
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• 2018

A problem exists in the conventional transportation cart applications, in which an external power supply with mechanical contact connection (bus bar connection) is required to drive the motor. Therefore, continuous effort for maintenance is required, aside from the expensive bus bar connector. To solve this problem, a self-electricity-generated transportation cart system without bus bar has recently been introduced. In this system, a battery needs to store the power of the generated wheel, and a boost converter, which converts the low battery voltage to high bus voltage to drive the motor inverter, is necessary. However, since the instantaneous large current required for starting the motor is supplied from the battery, a battery with large size and volume should be adopted to withstand this large current. In this study, a boost converter that can supply a large instantaneous current by using super Capacitor string is proposed. The proposed converter can be realized with a small size and volume compared with the conventional battery-fed boost converter. Operational principles, analysis, and design of the proposed converter are presented, and experimental results are provided to validate the proposed converter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.345-348
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• 2001

In this paper, we present a effective low-power technique which can reduce significantly the switching activity in instruction address bus, pipeline and I-cache. Using this method, named Guarded Operation, we has implemented address register. address bus architecture without complex hardware and designed loop buffer without tag. These architectures reduce 67% of switching activity with little overhead and also increase instruction-fetch performance.

• 한국초전도ㆍ저온공학회논문지
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• 제2권2호
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• pp.20-25
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• 2000

A CICC type superconducting bus-line electrically connecting a superconducting magnet to a power supply is cooled down to low temperature under the external magnetic field during operation. The thermal contraction during the cooling may be constrained by the supports which are installed to protect the bus-line from Lorenz magnetic forces. This constrained contraction causes thermal stresses in the bus-line to release thermal contraction. The minimum stress conditions in the bus-line may be optimized by controlling the supporting arrangement considering the thermal contraction and the external field. The analytical method to find optimal supports arrangement was suggested by using the beam theory, and numerical calculation using commercial code was performed to verify the suggested analytical optimization method.

• 대한전자공학회논문지SD
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• 제44권6호
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• pp.69-76
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• 2007

본 논문에서는 기존의 Bus-Invert Coding 계통의 여러 알고리즘들이 관습적으로 사용하던 Invert-line 을 제거하고 버스선을 통하여 코딩정보를 전송하는 새로운 설계방법을 제시하였다. Flip-Driver라고 하는 새로운 형태의 버스드라이버와 선택회로를 사용한 이 방식은 Invert-line을 사용하지 않을 뿐 아니라 코딩정보 전송 시 발생하는 추가적인 버스의 전이를 효과적으로 억제한다. 이러한 회로설계방식의 변환만으로도 여러 BI 알고리즘의 효율이 Invert-line을 사용할 때와 비교하여 40%-100% 증대시킬 수 있음을 실험을 통하여 검증하였다.

• 전자공학회논문지 IE
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• 제45권3호
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• pp.5-12
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• 2008

디지털 논리회로의 테스트 데이터와 전력소비를 단축시킬 수 있는 효율적인 테스트 방법을 제안한다. 제안 하는 테스트 방법은 테스트장비내의 테스트 데이터 저장 공간을 줄이는 하이브리드 run-length 인코딩 벙법에 기초하고, 수정된 Bus-invert 코딩 방법과 스캔 셀 설계를 제안하여, 스캔 동작시의 개선된 전력 단축효과를 가져온다. ISCAS'89 벤치마크 회로의 실험결과 고장 검출율의 저하 없이 평균 전력은 96.7%, 피크전력은 84%의 단축을 보이며 테스트 데이터는 기존 방법보다 78.2%의 압축을 갖는다.

• 대한전자공학회논문지SD
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• 제39권2호
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• pp.56-62
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• 2002

문턱전압 스윙 드라이버(threshold voltage swing driver)와 이중 감지 증폭기 리시버(dual sense amplifier receiver)를 가진 새로군 고속 저전압 스윙 온 칩 버스 (on-chip BUS)를 제안하였다. 문턱전압 스윙 드라이버는 버스에서의 전압상승 시간을 CMOS 인버터(inverter) 드라이버에서의 약 30% 이내로 줄여주고, 이중 감지 증폭기 리시버는 감지 증폭기 리시버를 사용하는 기존의 저전압 스윙 버스들의 데이터 전송량을 두 배 향상시켜 준다. 문턱전압 스윙 드라이버와 이중 감지 증폭기 리시버를 모두 사용할 경우, 온 칩 버스에서 사용하는 기존의 CMOS 인버터와 비교하여 제안된 방식은 약 60%의 속도 증가와 75%의 소모전력 감소를 얻는다.

• Journal of Power Electronics
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• 제7권3호
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• pp.181-190
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• 2007

This paper presents a novel circuit topology of a DC bus line series switch and parallel snubbing capacitor-assisted soft-switching PWM full-bridge inverter type DC-DC power converter with a high frequency planar transformer link, which is newly developed for high performance arc welding machines in industry. The proposed DC-DC power converter circuit is based upon a voltage source-fed H type full-bridge soft-switching PWM inverter with a high frequency transformer. This DC-DC power converter has a single power semiconductor switching device in series with an input DC low side rail and loss less snubbing capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge arms and DC bus line can achieve ZCS turn-on and ZVS turn-off transition commutation. Consequently, the total switching power losses occurred at turn-off switching transition of these power semiconductor devices; IGBTs can be reduced even in higher switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules can be realized at 60 kHz. It is proved experimentally by power loss analysis that the more the switching frequency increases, the more the proposed DC-DC power converter can achieve a higher control response performance and size miniaturization. The practical and inherent effectiveness of the new DC-DC converter topology proposed here is actually confirmed for low voltage and large current DC-DC power supplies (32V, 300A) for TIG arc welding applications in industry.

• 전력전자학회논문지
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• 제23권4호
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• pp.265-272
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• 2018

This paper proposes a new control method for the supercapacitor (SC) to compensate the pulsed load and to enhance the power quality of the DC microgrid. By coordinating the operating frequency, the SC is controlled to handle the surge current, while the low-frequency current component is dealt with by the remaining sources in the system. The operation mode of the SC unit is automatically changed based on the state of charge and DC bus voltage level. Meanwhile, the mismatch in the power demand is covered by the SC unit by regulating the DC bus voltage level. The effectiveness of the proposed method is verified experimentally by the prototype with two distributed generators and one SC unit.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.283-287
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• 2005

In this paper, one general approach is proposed for the design of power system that can be applicable for next generation LEO satellite application. The power system consists of solar panels, battery, and power control and distribution unit(PCDU). The PCDU contains solar array modules, battery interface modules, low-voltage power distribution modules, high-voltage distribution modules, heater power distribution modules, on-board computer interface modules, and internal DC/DC converter modules. The PCDU plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. We review the functional schemes of the main constitutes of the PCDU such as the battery interface module, the auxiliary supply module, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, spacecraft unit power distribution modules, and instrument power distribution module.