• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.593-600
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• 2016

The solar array regulator for low earth orbit satellites controls a operating point of solar array for suppling electric power to the battery and the other units. Because the control object is reversed, the new approach for large and small signal analysis is needed despite using buck-converter for power stage. In this paper, the steady state analysis of solar array regulator is performed in continuous conduction mode and discontinuous conduction mode, and the border condition for each mode is established. Also, the small signal model of solar array regulator is established in discontinuous conduction mode. Experiments are carried on in worst condition which the solar array regulator can face with discontinuous conduction mode. The results show that the solar array regulator is in stable.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.5
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• pp.429-436
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• 2016

Currently, many studies on green ships are under way. Fuel cell (FC) ships are of interest as future low-emission, fuel-efficient vessels. In this paper, a hybrid power management system for an FC ship was designed. The system consists of an FC, a battery, a unidirectional DC/DC converter, a bidirectional DC/DC converter, a filter, an inverter, and a propulsion component. To design the system, we analyze electric sources and converters, and create PLECS models of hybrid power management system. Then, we check the cold start sequence and perform a simulation to understand the characteristics of the hybrid power management system in an FC ship.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.16-23
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• 2020

An electric vehicle operates at high currents and requires real-time monitoring of the entire system for ensuring efficiency and safety of the vehicle. Current sensors are applied to drive the motors, inverters, and battery control systems, and are the key components to ensure constant monitoring of the magnitude and waveforms of the operating current. In this study, a heat treatment process condition to influence the performance of Permalloy current sensors was developed; the correlation between the output capacity, low-temperature characteristics, and high-temperature characteristics of the current sensor was studied; and the process was optimized to meet the required output accuracy and temperature characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.79-86
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• 2010

The characteristics and classification of UAV power plants were studied. The energy source for electric generation and power source for internal combustion engine for UAVs were compared. The advantage and drawbacks of power plants were analyzed respectively and the performance demand condition was suggested for next generation UAV power plant finally.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1829-1834
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• 2010

In order to prepare for the commercialization of Korean tilting train, this study was made on the pre-analysis of risk factors that can happen during operation, and emergency measures for safe operation of tilting train. The purpose of the study of emergency measures is to help to make tilting train run safely by making counteraction procedures for unusual situations such as train breakdown or accidents during the operation of a tilting train so that the engineer can quickly take care of each situation. Based on the items of emergency measures for EMU operated by Korean Railroad(or Korail), possible breakdown items during operation were selected and prioritized considering the occurring frequency and emergency level of each breakdown. In addition to these items, by adding items to represent tilting train's typicalfunctions such as tilting function error, tilting storage battery's electric pressure drop, etc, a total of62 emergency items were finally selected and measures for each item was made.

• Journal of IKEEE
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• v.22 no.3
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• pp.878-881
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• 2018

In this paper, experiments through performance evaluation under real operation environment were conducted. Transceiver and microcontroller shows the characteristics for the amount of current consumption and software protocol was optimized by controlling the time of Report Attribute and electric current level. To reduce current consumption when using battery, with designing transmission of the same amount of data as soon as possible, power consumption efficiency was enhanced.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1685-1687
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• 1996

Recently, conducting polymer has been much attracted as novel materials because of its electronic behavior and functional application by doping process. In this paper, we electrochemically synthesized polyaniline films under potential sweep conditions, which exhibit high electric conductivity about 200 S/cm. Specific energy of 600 Wh/kg and Ah efficiency 98% were achieved during the charge/discharge cycling using liquid electrolyte system. On the other hand, consequences of the cycling were 260 Wh/kg and 95% Ah efficiency using polyethylene oxide(PEO) based solid-state electrolyte system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1752-1758
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• 2014

This paper evaluates economic benefits of ESS (Energy Storage System) for peak load shaving in the substation of urban railway. For this purpose, the method to determine capacities of ESS and PCS (Power Conditioning System) for peak load shaving is proposed. Then the economic benefits of those devices are evaluated using net present value method. The proposed methods are applied to actual measurements of loads in the substation of urban railway. The results show that electric power costs can be reduced and the economic benefits of ESS for peak load shaving mainly depends on the price of battery.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.617-618
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• 2015

최근 지구온난화, 배기가스 배출에 의한 대기오염, 화석에너지 고갈에 따라 대체에너지에 대한 관심이 많아지고 있고, 이에 따라 세계 각 국가들이 해당 분야에 관한 연구를 활발히 진행하고 있다. 그 핵심 과제의 하나는 전기자동차이며 최근 전기차에 대한 관심이 점점 고조되고 있고 전기차의 실 구매도 많아짐에 따라 전기차의 핵심이라 할 수 있는 배터리에 관한 연구가 활발히 진행되고 있다. 전기차에 사용되는 배터리는 높은 에너지 밀도, 높은 전력 밀도, 긴 수명과 친환경적인 장점을 가지고 있어야 한다. 하지만 안전성, 지속성, 획일성, 가격 등에 대하여 배터리의 사용에 한계가 있다. 여기에서는 배터리 관리 시스템(BMS)을 비롯한 배터리의 주요 연구 테마들에 관한 현재까지 연구동향을 소개하고자 한다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.6
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• pp.619-624
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• 2015

Owing to miniaturization and low-power electronics, mobile, implanted, and wearable devices have become the main trends of electronics during the past decade. There has been much research regarding energy harvesting to achieve battery-free or self-powered devices. The optimal design problems of a double-pendulum kinetic-energy harvester from human motion are studied in this paper. For the given form factor, the weight of the harvester, and the known human excitation, the optimal design problem is solved using a dynamic non-linear double-pendulum model and an electric generator. The average electrical power was selected as the performance index for the given time period. A double-pendulum harvester was proven to be more efficient than a single-pendulum harvester when the appropriate parameters were used.