• Journal of Power Electronics
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• 제14권1호
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• pp.183-193
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• 2014

Due to the requirements for high reliability and accuracy, safety issues for airbag ignition systems need to be studied. In this paper, a high-voltage piezoelectric converter is designed to improve these requirements in airbag ignition systems. The proposed converter includes an inverter drive circuit, a Rosen piezoelectric transformer (PZT), an output circuit and a feedback control circuit. The key components of the high-voltage piezoelectric transformer are analyzed in detail. In addition, the proposed converter system is simulated and implemented for testing. The experimental results show that when the power supply is turned on, the charging time is less than 800ms. Furthermore, the output voltage of this converter can be kept between 2.9kV and 3.1kV, under high-efficiency constant current charging mode and zero-voltage switching conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.346-351
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• 1999

This paper is a research for removing the hunting which came about during the parallel running of the alternators which four-pole six-phase have the converter with twelve diodes to rectify all the waves. Druing the parallel running the hunting came about under the period of 0.2-0.3{sec} not when it's load was the resistance but the capacity at the rpm band 1575[rpm] 1690[rpm] This hunting in our judgement was not come about from the general hunting causes which have been already known to but the special example. And so we checked that the hunting came about or not as per the changes of the rpm exciting current load current and converter and converter output voltage and the following facts were revealed. -The hunting occured during the constant voltage charging where r. p. m band is from 1575[rpm] to 1690[rpm] - The hunting did not came about during the constant power charging in which there was the large difference between the converter output voltage and the battery voltage. -The hunting did not came about in the low rpm band. We could see from the above facts that the existence of the hunting inducing point at the con-stant voltage charging band was the direct cause of the hunting. After trying every possible means to remove the hunting inducing point we could know that the modification of the synchronous generator is suitable for he purpos in view of the small engine room.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.94-98
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• 1994

In this study, the thermally stimulated current(TSC) of corona charged PTFE film was studied and the simulation of corona charging process was also calculated by finite element method. The electrets which were formed by appling high voltages(DC-5∼-8[kV]) to PTFE film were experimented to measure TSC in the temperature range of -100∼+200 [$^{\circ}C$] and then the finite element method was accomplished to examine corona charging process using a obtained physical constants. It is confirmed that the charging negative corona is profitable as the applications are manufactured because the time constant of negative corona is much larger than it of positive corona. And it is attempted to estimate the corona charging process in space using simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2508-2511
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• 1999

A non-contact battery charger which transfers energy using magnetic field without any electrical contacts is designed using half-bridge series resonant converter. This converter utilizes series resonance to reduce the undesirable effect of large leakage inductance of the non-contact transformer and ZVS operation can reduce switching losses. In this paper. analysis and design procedure of half-bridge series resonant converter with non-contact transformer is presented. Input voltage is 85VAC ${\sim}$ 270VAC, output voltage and current is 4.1V and 800mA, respectively. Furthermore, a method for calculating the secondary current of the transformer to control battery charging current in constant current charging mode which is required for litium-ion battery is proposed and the performance is verified from experiments.

• 전력전자학회논문지
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• 제20권3호
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• pp.280-289
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• 2015

A high-efficiency full-bridge DC-DC converter with a current-doubler rectifier and an asymmetric pulse-width modulation is proposed. Through the asymmetric pulse-width modulation, the proposed converter achieves zero-voltage switching of power switches without the circulating currents. The proposed converter reduces the output current ripple through the current-doubler rectifier. A control strategy is suggested for the proposed converter to charge battery banks. A constant current and constant voltage charging is performed. The proposed converter achieved a higher efficiency compared with the conventional full-bridge DC-DC converter with a phase-shift modulation. The performance of the proposed converter is evaluated by the experimental results for a 1.0 kW prototype circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.204-205
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• 2016

Human power is not dependent on other energy sources, but rather is a source of power for ourselves. Human power, the cleanest energy in the world, can be our future. Therefore, we should be interested in sustainable alternative energy. This paper solves the uneven power generation by utilizing the energy storage capability of the flywheel. Therefore, it improved the efficiency by 5% compared to the existing generation method. DC generators produce power at variable speed operation. The constant voltage was generated from the DC-DC converter to the duty ratio control. Therefore, the charging efficiency is improved by 5% by the constant voltage charging of the battery. And it can suppress the decrease of the output due to the circulation current due to the deviation of the output voltage in parallel operation of the pedal generator.

• 조명전기설비학회논문지
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• 제19권2호
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• pp.1-6
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• 2005

본 연구에서는 광고 조명으로 인한 에너지 소비를 극소화하기 위하여 OF-LED(Optical-Fiber LED)를 이용한 에너지 절약형 광고 조명 시스템에 대하여 연구하였다. 제안한 OF-LED광고 조명 시스템은 에너지 소비가 획기적으로 저감되고 시스템의 소형화가 가능하며, 부조일이 높은 장마철을 제외하고는 태양광 발전만으로 운영하는 큰 장점을 가진다. 태양전지의 출력 특성에 의한 배터리의 최단$\cdot$최적 충전을 위해 정전류$\cdot$정전압 제어법(CCVC)과, IncCond알고리즘을 병행하여 적용하였다 그리고 원칩 마이크로프로세서로 디스플레이 제어와 충 방전제어를 동시에 수행하도록 하였다. 이를 실험을 통하여 제시된 시스템의 유용성을 입증하였다.

• 인터넷정보학회논문지
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• 제24권1호
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• pp.87-97
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• 2023

충전기 인프라 시설은 일정한 전력 공급량을 기반으로 설계 및 설치되어 있다. 초기 설계된 충전 시설은 급속히 성장하는 전기 차량의 충전을 한정된 공급 전력량 기반으로 지원한다. 또한, 현재 상용차량은 완전 충전만 가능하며, 급속 균등 충전 방식으로 지원된다. 하지만 상용차량은 정해진 스케줄에 따라 운영되기에 탄력적인 충전이 필수적이다. 본 논문에서는 전기 차량의 급속한 성장 및 증가에 따라 동일 전력량을 기반으로 상용 버스의 고정 스케줄 기반 충전 스케쥴링 및 전력 분배 기법을 활용하여 20%이상 효율 향상된 전력 운영방안을 제시한다.

• Tribology and Lubricants
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• 제18권1호
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• pp.16-23
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• 2002

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of ER electrode distance. From the experimental results the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also tile compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, tile yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.138-145
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• 2001

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of compressing ER electrode. From the experimental results, the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also the compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, the yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.