• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.866-871
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• 2003

In automobile, the introduction of electronically commutated motors has been accompanied by a proliferation of electronic devices. With this proliferation of electronic devices, an emphasis has been placed on EMC issues. This paper is proposed to use SRM as a radiator cooling fan in automotive applications. To drive SRM, Energy efficient C-dump converter is applied. It is verified more efficient than other converters through simulation and experiments. And also SRM is valid automotive applications that have strict EMC standards. It is compared SRM with BLDC and DC motor by experiments.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.886-890
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• 2003

This paper introduces the combined test results of the traction system for KHST(Korean High Speed Train: hereafter refer to KHST). The main purpose of this combined test is to verify the performance of the traction system that is designed to operate up to maximum 350km/h speed. Combined test system consists of a traction transformer, two AC-DC PWM converters, a PWM Inverter, two traction motors and flywheel system. Flywheel system represents equivalent model of the train inertia. Also traction control system and MASCON Interfaces are included. Various kinds of experiments are performed to prove total traction system performance and detail waveforms are described

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.10
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• pp.148-156
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• 1996

Increasing the switching frquency is essential to achieve the high density of switched mode power supplies, but this leads to the increase of switching losses. A number of new soft switching converters have been presented ot reduce switching losses, but most of them may have some demerits, such as the increase of voltage/current stresses and high conduction losses. To overcome these problems, the ZVT-PWM converter has recently been presented. in this paper, the operation characteristics of the ZVT-PWM boost converter is analyzed, and the steady-states (DC) and small-signal model of this converter are derived and analyzed, and then the transfer functions of this converter are derived. The transfer functions of ZVT-PWM boost converter are similar to those of the conventional PWM boost converter, but the transfer characteristics are affecsted by te duty ratio and the switching frequency.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.467-468
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• 2013

In this paper, a switching control strategy of bidirectional converter for energy storage system in photovoltaic hybrid modules is proposed. The bidirectional converter for energy storage system (ESS) with battery is connected with DC link in parallel which is located between current source flyback converters(CSFC) and unfolding bridge. Because CSFC generates rectified sinusoidal current, the bidirectional converter requires suitable control strategy. Therefore, a theoretical analysis of the proposed switching control strategy is presented. And, validity is confirmed through simulation results.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.311-312
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• 2013

본 논문에서는 자성체의 직류중첩 (DC-Bias)특성이 영향을 미치는 공진형 컨버터의 효율을 계산하기 위한 시뮬레이션을 구성한다. 이를 위해 PSIM의 saturable core를 이용하여 core coefficient를 실제 설계 사양과 동일하게 적용 및 모델링한다. 시뮬레이션 결과를 통해, 자성체에 흐르는 전류의 크기에 따라 변화하는 투자율이 공진형 컨버터의 동작 및 효율에 미치는 영향을 분석한다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.114-121
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• 2004

Switched reluctance motors have received much attention as a driving means for various industrial applications because they have simple construction, low cost and high efficiency. Nevertheless, the requirements of drive converters make it difficult to lower the overall system cost as compared with the DC motor application. Single phase switched reluctance motors (SPSRMs) provide a solution to the high cost problem since the number of switching power devices can be reduced and consequently the trials for application are increased. However, research involving SPSRMs, especially in the area of design work, is insufficient. This paper introduces a novel design methodology of single phase SRM. The design work for SPSRM comprises the determination of many variables such as stator and rotor pole arc as well as on, off and so on. Managing all variable combinations leads to lengthy computation time and a fault in the design process. For that reason, a reliable technique and brief procedure term are required in SPSRM design.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.341-342
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• 2014

VSC-HVDC system based on Modular Multilevel Converter (MMC) is an emerging technology since compared to the conventional VSC-HVDC system an MMC presents several advantages such as modularity, low dv/dt, low harmonics, and low switching losses. In this paper, a comprehensive control strategy of an MMC-based VSC-HVDC system is proposed. In contrast to the conventional system control strategy, the DC side of the MMC operates as a controlled voltage source by the proposed method, and the dynamics of the transmission line voltage and current can be actively controlled. Validity of the proposed strategy was verified by 201-level full-scale computer simulation.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.227-228
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• 2015

본 논문에서는 Optocoupler 절연형 오프라인 플라이백 변환기 궤환 단의 직류 바이어스 해석 기법을 제안한다. 직류 바이어스 해석을 통해 목표한 Current Transfer Ratio(CTR)를 얻고 Junction Capacitance($C_j$)를 측정하여 제어기 설계에 적용시켜 안정도 및 성능을 측정하였다. NCP1230, PC817, TL431 IC를 이용하여 플라이백 변환기의 제어회로를 제작하였고, 시뮬레이션을 이용해 직류 바이어스 해석 기법의 타당성을 검증하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1418-1423
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• 2007

The topology of LLC half bridge resonant converter provides ZVS characteristic. The voltage stress and current stress are smaller than that of the general resonant converters. So the LLC HB resonant converter can be considered as a optimal circuit for the notebook computer adapter. In the adapter design, we should consider the weight, the size and the overheat of the adapter. Thus the higher efficiency is an essential particular. First of all, the optimal design of transformer is the most important facts. Some parameters should be considered in order to get the highest efficiency. The adapter is designed through the considering of these parameters including the PFC circuit as the pre-regulator. It converts AC line input into about DC 390V link voltage of the LLC HB converter input and the converter has 16V/90W ratings. The efficiency measured is about up to 93%.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.79-81
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• 2020

임계모드 (Critical conduction mode, CrM) 동작을 하는 PFC 컨버터는 주파수 변동을 통한 Valley switching 동작으로 인하여 높은 효율 및 양호한 EMI 특성을 가진다. 하지만 Peak 부하가 큰 시스템에서 CrM 설계를 하게 되면 정격부하에서 비교적 높은 주파수의 동작이 불가피하여 시스템 효율이 나빠지고 높은 DC-bias 확보를 위해 인덕터 크기가 커지게 된다. 따라서 본 논문에서는 고효율 및 인덕터 사이즈 저감을 위한 임계모드에서 동작하는 두 개의 교차형 PFC 컨버터의 병렬 구동에 대해서 이야기하고자 한다.