• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 F
• /
• pp.1860-1862
• /
• 1998

This Paper presents a novel resonant switching Watkins-Johnson DC-DC converters. In the proposed converters, the basic steady-state analysis of the have been presented for the ZVS type Watkins-Johnson converter. From the results, it is shown that the output voltage of the converter is independant of load resistance, and is determined only by the switching frequency. Consequently, a design procedure is presented that minimizes voltage stress to the switch while maintaining ZVS for all loads.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2010년도 하계학술대회 논문집
• /
• pp.240-241
• /
• 2010

Research on modification and replacement of conventional AC distribution system to DC distribution system has been widely conducted. When DC system is applied, it is possible to improve energy transferring efficiency because most of the home appliances are electric loads which require DC input voltage. Furthermore, compatibility with renewable energy sources and secondary batteries should be improved as they are DC based power sources. To design energy efficient DC system, it is important to understand the load characteristics of the electric devices. In this paper, the electric appliances are classified to 3 types: motor, heating, and electric loads and their typical power consumptions are shown. Load patterns of load which can be used in analyzing the designed system are modeled according the statistics. Feasibility of the developed load patterns are verified by applying it in distribution system design tool.

• Journal of Power Electronics
• /
• 제17권3호
• /
• pp.632-640
• /
• 2017

Input series output independent (ISOI) dc-dc converter systems are suitable for high voltage input and multiple output applications with low voltage rating switches. This paper proposes a novel control strategy consisting of one output voltage regulating (OVR) control loop and n-1 (n is the number of modules in the ISOI system) input voltage sharing (IVS) control loops. An ISOI system with the proposed control strategy can be applied to applications where the output loads of each module are the same. Under these conditions, IVS can be achieved and output voltages copying can be realized in an ISOI system. In this control strategy there is only one controller for each module and the design process of the control loops is simple. Since no central controller is needed in the system, modularity of the system is improved. The operation principle of the new control strategy is introduced and the control effect is simulated. Then the output power and voltage characteristics of an ISOI system under this new control strategy are analyzed. The stability of the proposed control strategy is explored base on a Hurwitz criterion, and the design guide line of the control strategy is given. A two module ISOI system prototype is fabricated and tested in the laboratory. Experimental results verify the effectiveness of the proposed control strategy.

• 한국전자파학회논문지
• /
• 제26권5호
• /
• pp.521-524
• /
• 2015

본 논문에서는 재구성이 가능한 다중포트 전력증폭기를 이용해 선택적으로 무선 전력 전송을 할 수 있는 구조를 제안한다. 제안된 무선 전력 전송 구조는 FPGA에 의해 제어되는 입력 위상 가변부, 두 개의 Class-E급 전력증폭기, 4-포트 직교전력 결합기, 두 개의 부하 코일로 구성된다. FPGA에 의해 제어되는 입력 위상부에 의해 두 코일에 전력이 선택적으로 1:1, 2:0, 0:2의 비율로 분배된다. 제작한 시스템은 측정 결과, 125 kHz에서 1 W DC 전력을 전달하였다. 각 개별 전력증폭기는 79 % 효율을 가졌으며, 정류변환을 포함한 최종 DC-DC 변환효율은 40 % 이상을 보였다.

• 한국정보통신학회논문지
• /
• 제15권9호
• /
• pp.1979-1984
• /
• 2011

본 논문은 가정내 주 배전시스템으로 DC 전력을 사용하기 위한 그린 Platform을 제시하였다. 제안한 Platform은 공통 DC bus와 양방향 DC 그리드를 갖는 구조이며 DC bus에 연결된 장비들은 에너지원(source), 부하(load), 양방향 장비(bi-directional devices)로 구분하였다. 현재의 기술을 바탕으로 전압과 시스템을 DC로 변환하고 부하에 직접 연결 시킴으로서 시스템 효율을 증가시키기 위한 구축 방법을 제시하였다.

• 조명전기설비학회논문지
• /
• 제17권6호
• /
• pp.113-118
• /
• 2003

비선형 부하는 고조파 발생원으로 고조파 전압원과 고조파 전류원의 두종류로 분류된다. 직렬동조필터는 개인용 컴퓨터 부하와 같이 직류 캐패시터가 있는 비선형 부하로 고조파 전압원에 매우 효과적으로 고조파를 저감시킨다. 병렬동조필터는 교류 구동장치와 같이 직류 리액터가 있는 비선형 부하로 고조파 전류원에 적합하다. 본 논문에서는 직렬 및 병렬 동조 필터의 고조파 저감 특성과 비교를 검토하고 실험하였다. 국제 고조파 관리 기준인 IEC 1000-3-2 으로 직렬 및 병렬 동조필터의 고조파 저감 효과를 평가하고자 한다.

• 대한전자공학회논문지SD
• /
• 제48권12호
• /
• pp.23-30
• /
• 2011

본 논문은 경부하에서 전압 안정화 특성을 향상 시키고 독립적인 다중 출력을 생성 시키기 위해 부궤환 선택 회로를 갖는 단일 인덕터 다중 출력(SIMO) 직류-직류 변환기를 설계하였다. 일반적으로 기존의 SIMO 직류-직류 변환기는 고정된 부궤환 루프를 가지고 있어 경부하에서 정확한 출력을 생성 할 수 없다. 제안하는 부궤환 선택회로를 갖는 SIMO 직류-직류 변환기는 0.35um 2-poly 3-metal BCDMOS를 이용하여 설계 하였다. 이변환기는 1.5V 입력과 2.5V, 3.0V의 2중 출력을 가지고 있다. 최대 전력변환효율은 부하가 10mA이때 59%에서 50mA일 때 85%를 가지고 있다.

• 전력전자학회논문지
• /
• 제17권1호
• /
• pp.21-26
• /
• 2012

In recent years, DC distribution systems are becoming hot issue due to the increase in digital loads and DC generation systems according to the expansion of renewable energy technologies. However, removing the fault current in DC grids is comparably difficult since the current in DC grids has no zero-crossing point like in AC grids. Thus, developing dedicated DC circuit breakers for DC grids is necessary to get safety for people and electrical facilities. This paper proposes magnet arc extinguishing method to develop a 300[$V_{DC}$]/10[A] DC circuit breaker. The performance of the proposed DC circuit breaker was verified by an experimental circuit breaker test system built in this research.

• 전기학회논문지
• /
• 제63권10호
• /
• pp.1479-1484
• /
• 2014

This paper deals with regenerative energy in railway system which one of the largest customer in terms of load capability. Unlike the other loads of power system, loads of railway systems change in time and space. It has a characteristic amount of generating regenerative energy by frequent starting and braking in railway system. Therefore, it is expected higher utilization in railway system than the other systems. The purpose of DC power supply simulation is analyzing backed energy, regenerative energy by each railway vehicle and substation. In this paper, regenerative energy utilization are analyzed using DC power supply simulation and it is performed changing major influence on the design such as the number of installing absorber, internal resistance value, no-load voltage value at substation or operating parameters at regenerative energy utilization. After simulating, results are compared and analyzed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.239-241
• /
• 2008

A powered system with fuel cell is regarded as a high current and low voltage source. Effects of the loads on the electrical power source are important to optimize the integrated power system. The design parameters of the system should be chosen by taking into account the characteristics of the fuel cell, so the costs of the power system at given operating conditions can be reduced. Furthermore, the dynamics characteristic of the system is crucial to acquire performance in applications, particularly interactions between loads and the fuel cell system. Currently, no integrated simulation has been approached to analyze interrelated effects. Therefore, the dynamic models of power conversion system with a PEM fuel cell that includes the PEM fuel cell stack, DC/DC converter and associated controls is developed. Electric lads for the system are derived by using a power theory that separates a load current into active, reactive, distortion or a mixed current component. Dependency of the DC capacitor on the loads are analyzed.