• 전자공학회논문지 IE
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• v.47 no.2
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• pp.13-20
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• 2010

This paper describes a current mode PWM DC-DC converter IC for battery charger and supply power converter for portable electronic devices. The maximum supply voltage of IC is 40[V] and 2.8[V]~330[V] DC input power is converted to higher or programmed DC voltage according to external resistor ratio or wire winding ratio of transformer. The maximum supply output current is 3[A] over and voltage error of output node is within 3[%]. The whole circuit needed current mode PWM DC-DC converter circuit is designed. The package dimensions and number of external parts are minimized in order to get a smaller hardware size. The power consumption is smaller then 1[mW] at stand by period with supply voltage of 3.6[V] and maximum energy conversion efficiency is about 86[%]. This device has been designed in a 0.6[um] double poly, double metal 40[V] CMOS process and whole chip size is 2100*2000 [um2].

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.182.2-182.2
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• 2012

If the satellite has the magnetic material or magnetic moment, the satellite is affected by the earth magnetic field by the space environment in Geostational orbit. The aim of this paper is to assess the satellite magnetic momentum which is an input to ADCS(Altitude Determination Control Subsystem) analyses to assess spurious torques. The magnetic momentum at satellite level is due to magnetic momentum generated by each unit which is due to internal currents circulation or to the presence of magnetic components. Also the magnetic momentum at satellite level is due to circulation of the DC supply current from PSR(Power Supply Regulator) to each unit. As introducing the intrinsic contribution of each unit and the magnetic moment based on the current return through the structure, this paper assess the satellite magnetic moment.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.61-61
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• 2003

과학위성 1호는 2003년 9월 26일 러시아 플레세츠크 발사장에서 발사되었다. 고도 690Km 상공에서 원형궤도를 그리며 우주에서의 임무수행을 시작했다. 과학위성 1호의 1차 전지는 태양으로부터 생산된 전기에너지를 사용하며, 2차 전지는 NiCd Battery를 사용한다. 이와 같이 1차 전지와 2차 전지를 최적의 상태로 제어하여 위성의 전력공급시스템으로써의 역할을 수행하게 될 과학위성 1호 전력시스템은 크게 Solar Power Regulator(SPR), Power Supply Unit(PSU), Power Distribution Unit(PDU), 및 Battery Cell Monitor / Pyrotechnic Device Support Equipment(BM/PDSE)로 구성 되어있다. 따라서, 본 논문에서는 과학위성 1호의 전력공급을 담당하는 System Unit 별 기능, 신호흐름, 전력분배 원칙 등에 대하여 연구하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.4
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• pp.186-192
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• 2002

In this paper, interleaved boost power factor corrector(IBPFC) is applied as a pre-regulator in switch mode power supply. IBPFC can reduce input current ripple and effectively increase the switching frequency without increasing the switching losses, because input current is divided each 50% by two switching devices. IBPFC can be classified as three cases by duty ratio condition in continuous current mode and be carried out state space average modeling. According to the modeling, steady and transient state analysis is performed by steady elements and perturbation element. Control transfer function is derived for design of control system.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.95-100
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• 2006

The COMS(Communication, Ocean and Meteorological Satellite) EPS(Electrical Power Subsystem) is derived from an enhanced Eurostar 3000 version. Eurostar 3000 EpS is fully autonomous operation in nominal conditions or in the event of a failure and provides a high level of reconfigure capability. This paper introduces the COMS EPS preliminary design result. COMS EPS consists of a battery, a solar arrat wing, a PSR(Power Supply Regulator), a PRU(Pyrotechnic Unit), a SDAM(Solar Array Drive Mechanism) and relay and fuse brackets. COMS EPS can offer a bus power capability of 3 kW. The solar array is made of a deployable wing with two panels. One type fo solar cells is selected ad GaAs/Ge triple junction cells. Li-ion battery is base lined with ten series cell module of five cells in parallel. PSR associated to battery and solar array wing generates a power bus fully regulated at 50 V. Power bus os centralized protection and distribution by relay and fuse brackets. PRU provides power for firing actuarors devices. The solar array wing is rotated by the SADM under control of the attitude orbit control subsystem. The control and monitoring of the EPS, especially of the battery, is performed by the PSR in combination with the on-board software.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.101-107
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• 2016

The main target in this paper is the localization of VME Type EPSM in Generator Exciter(EX2100) System. Developed EPSM has the compatibility with the existing product in the structure and shape and electrical feature and so on, but it has a much improved capacity and reliability in comparison with origin company product. this paper, to improve these functions, put emphasis on protection, monitoring, power capacity increase(over 120%), an enlarged scale of input voltage supply, AC/DC dual voltage use and so on. After manufacturing product localization, it was carried out several tests for the performance and reliability verification of developed product. These tests were performed in Authorized Inspection Agency(KTL) and field application test and maker self-test were additionally performed. Finally, the results of all tests were "success".

• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.75-79
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• 2013

A power distribution network (PDN) is a network that provides connection between the voltage source supply and the power/ground terminals of a microprocessor chip. It consists of a voltage regulator module, a printed circuit board, a package substrate, a microprocessor chip as well as decoupling capacitors. For power integrity analysis, the board and package layouts have to be transformed into an electrical network of resistor, inductor and capacitor components which may be expressed using the S-parameters models. This modeling process generally takes from several hours up to a few days for a complete board or package layout. When the board and package layouts change, they need to be re-extracted and the S-parameters models also need to be re-generated for power integrity assessment. This not only consumes a lot of resources such as time and manpower, the task of PDN modeling is also tedious and mundane. In this paper, a block-based PDN modeling is proposed. Here, the board or package layout is partitioned into sub-blocks and each of them is modeled independently. In the event of a change in power rails routing, only the affected sub-blocks will be reextracted and re-modeled. Simulation results show that the proposed block-based PDN modeling not only can save at least 75% of processing time but it can, at the same time, keep the modeling accuracy on par with the traditional PDN modeling methodology.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.397-403
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• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.749-763
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• 2022

The fulcrum of economic development is a sustainable supply of electricity. Nigeria is plagued with blackouts, with one of the lowest per capita electricity consumption in the world (circa. 120 kWh per capita). Hence, policies have been instigated to integrate electricity generation from nuclear power plants (NPP) on or before 2027. However, a critical requirement for NPP generation is the implementation of robust human resource development (HRD) programs. This paper presents the perspective of Nigeria in assessing human resources needs over the entire NPP lifecycle following the milestone approach and employing the IAEA's Nuclear Power Human Resource (NPHR) modeling tool. Three workforce organizations are in focus including the owner/operator, regulators, and construction workers following three decades timeframe (2015-2045). The results indicate that for the study period, a maximum of approximately 9045 personnel (73% construction workers, 24% owner/operator, and 3% regulators) should be directly involved in the NPP program just before the commissioning of the third NPP in 2033. However, this number decreases by about 73% (2465 personnel including 94% operator and 6% regulator) at the end of the study timeframe. The results can potentially provide clarity and guidance in HRD decision-making programs.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.62-70
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• 2008

The paper made a description of the method for numerical analysis and modeling of a proportional pressure control valve by bondgraph. The valve is a three port pressure regulator valve, consists of two subsystems; a proportional solenoid and a spool assembly. A purpose of this study is to analysis the dynamic characteristics of the valve using bondgraph method and to verified results that each of parameters has an effect on modeling. It considered the effect which the presence of solenoid, flow coefficient and non-linearity of resistance causes in the valve modeling. In particular, it is analyzed the effect that the solenoid interacted with modeling results and characteristics of the nonlinear resistance through orifice on the supply and discharge side of valve. Thus this paper described method to present nonlinear characteristics by bondgraph modeling method, so that we could know easily result that each parameters has an effect on the modeling.