• 전기학회논문지P
• /
• 제57권2호
• /
• pp.72-78
• /
• 2008

The speed variation of SRM is fulfilled throughout a transition from chopping control to single pulse operation. (i,e., low speed to high speed operation). It is unsatisfied with performance at all operational regimes. In this paper, the operational performance of SRM can be improved by using current hysteresis control method. This method maintains a generally flat current waveform. At the high speed, the current chopping capability is lost due to the development of the back-EMF. Therefore SRM operates in single pulse mode. By using zero-current switching and zero-voltage switching technique, the stress of power switches can be reduce in chopping mode. When the commutation from one phase winding to another phase winding, the current can be zero as fast as possible in this period because several times negative voltage of DC-source voltage produce in phase winding. This paper is compared to performance based on conventional C-dump converter topology and the proposed resonant C-dump converter topology. Simulation and experimental results are presented to verify the effectiveness of the proposed circuit.

• 대한전자공학회논문지SD
• /
• 제45권9호
• /
• pp.96-102
• /
• 2008

SoC의 버스 구조에는 싱글버스와 다중버스로 구분된다. 싱글버스는 전송을 원하는 여러 개의 마스터 중 선택된 하나의 마스터만이 데이터 트랜잭션을 수행할 수 있다. 반면에 다중버스는 개별적으로 동작이 가능한 버스를 브리지를 통해 연결하여 각각의 버스에서 여러 데이터를 병렬 처리할 수 있다. 그러나 현재의 버스에서 다른 버스로 데이터 통신을 수행할 경우, 레이턴시가 급격하게 증가할 수 있다. 게다가, 다중버스의 성능은 마스터의 개수, 슬레이브의 종류 등에 따라 쉽게 바뀔 수가 있다. 이에 본 논문에서는 TLM(Transaction Level Model) 시뮬레이션 방법을 이용하여 마스터의 개수, SDRAM, SRAM, 레지스터 등의 슬레이브 종류에 따른 싱글버스와 다중버스 아키텍처의 성능을 정량적으로 비교 분석하였다.

• Journal of Communications and Networks
• /
• 제3권4호
• /
• pp.342-350
• /
• 2001

The Internet routing instability, or the rapid fluctuation of network reachability information, is an important problem currently facing the Internet engineering community. High levels of network instability can lead to packet loss, increased network latency, and delayed routing convergence. At the extreme, high levels of routing instability can lead to the loss of internal connectivity in wide-area networks. In this paper, we investigate the variation of domain degree and domain count of the inter-domain network over time by using linear regression model in order to analyze the topology variation of inter-domain network. We Also propose an efficient policy management model to reduce the instability in the inter-domain routing system. The proposed model can be used to identify whether a routing policy is adequate to reduce convergence time that is required to return to a normal state when BGP routing instability happens. Experimental analysis shows that the proposed model can be used to set up routing policy in domains for the purpose of minimizing the effects and the propagation of BGP routing instability.

• 한국위성정보통신학회논문지
• /
• 제9권2호
• /
• pp.7-11
• /
• 2014

본 논문에서는 $0.5{\mu}m$ p-HEMT 공정을 이용한 MMIC 주파수 혼합기를 설계하였다. 본 주파수 혼합기는 Local 신호전력이 -4 ~ 4 dBm에서 유사한 성능을 갖도록 설계하여 local 신호의 변화에 따른 변환 성능이나 선형 성능이 일정하게 유지 되도록 하였다. 이와 같은 특성을 갖도록 하기 위해 새로운 형태의 FET를 이용한 피드백 회로를 구성하여, LO신호전력의 변화에 따른 성능 변화를 최소화 하였으며 넓은 주파수 대역에서 사용 할 수 있는 MMIC 주파수 혼합기 성능을 얻었다. 설계결과 LO신호전력이 -4 ~ 4dBm일 때, 0.5 ~ 2.6GHz의 주파수 범위에서 변환손실이 6 dB에 IIP3가 30 dBm 이상의 우수한 성능을 갖는 설계 결과를 얻었다.

• Journal of Power Electronics
• /
• 제5권2호
• /
• pp.120-128
• /
• 2005

This paper deals with the analysis of switched reluctance motor drives for different drive circuit topologies used in automobile. So we attempt to improve the weaknesses associated with the asymmetric bridge converter in the limited internal environment of automotive application. Two kinds of c-dump converters are tested in terms of dump capacitor voltage, speed response according to the variation of advance angle and efficiency for the radiator cooling-fan drive of an automobile. They enable more economical and efficient converter topology for automobile industries. This paper describes the performance characteristics of 12V-250W-3000rpm SRM drives for automotive application. Computer simulation and experiment results are then presented to verify the performance of the two kinds of c-dump converters.

• Journal of Power Electronics
• /
• 제6권4호
• /
• pp.330-339
• /
• 2006

This paper deals with novel electronic ballast based on single-stage power processing topology using a symmetrical half-bridge inverter and current injection circuit. The half-bridge inverter drives the output parallel resonant circuit and injects current through the power factor correction (PFC) circuit. Because of high frequency current injection and high frequency modulated voltage, the proposed circuit maintains the unity power factor (UPF) with low THD even under wide variation in ac input voltage. This circuit needs minimum and lower sized components to achieve the UPF and high efficiency. This leads to an increase in reliability of ballast at low cost. Furthermore, to reduce cost, the electronic ballast is designed for two series-connected fluorescent lamps (FL). The analysis and experimental results are presented for ($2{\times}36$ Watt) fluorescent lamps operating at 50 kHz switching frequency and input line voltage (230 V, 50 Hz).

• 조명전기설비학회논문지
• /
• 제13권3호
• /
• pp.124-128
• /
• 1999

본 연구는 고주파 직렬공진 인버어터를 이용한 20[kHz],10[kHz]급 고효율 유도가열장치에 관한 것이다. 치가열체인 부하변동에 대해서는 인버어터의 직류 입력 전압을 가변시키고 인버어터 스윗칭을 공진 주파수를 추종해 동작시킴으로써 무료전력을 최소화 할 수 있는 회로 구성을 제시하였다. 그리고 시뮬레이션과 실험을 통해 유도가열장치의 인버어터 역률이 약0.96으로 양호함을 알 수 있었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
• /
• pp.346-349
• /
• 2004

The design of DC-DC converters for power electronic interfaces in power management systems for Hybrid Electric Vehicle (HEV) is a very challenging task. In this paper, the considered topology is the hi-directional buck-boost converter and inverter system. If we make the converter side DC link current the same as the inverter side DC link current in a converter-inverter system, no current will flow through the BC link capacitor and as a result, no DC link voltage variation occurs. This leads to the possibility of reducing small th size of DC link capacitors which are expensive, bulky. Therefore we propose the converter current controller which can manage to match inverter and converter current at the DC link.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2014년도 추계학술대회 논문집
• /
• pp.66-67
• /
• 2014

Stabilization of the DC bus voltage is an important task in DC-AC microgrid system with renewable energy source such as solar system. A battery energy storage system (BESS) has become a general solution to stabilize the DC-bus voltage in DC-AC microgrid. This paper develops the analog BESS controller which requires neither computation nor dc-bus voltage measurement, so that the system can be implemented simply and easily. Even though others methods can stabilize and control the DC-bus voltage, it has complicated structure in control and low adaptive capability. The proposed topology is simple but is able to compensate the solar source variation and stabilize the DC-bus voltage under any loads and distributed generation (DG) conditions. In addition, the design of analog controller is presented to obtain a robust system. In order to verify the effectiveness of the proposed control strategy, simulation is carried out by using PSIM software.

• 한국전기전자재료학회논문지
• /
• 제24권1호
• /
• pp.57-63
• /
• 2011

Dielectric Barrier Discharge (DBD) reactor with sinsodual AC type of power supply is very widely adopted for its compact size and effective discharging mechanism to generate high density of ozone radicals. However, at the aspect of design on power supply, its optimal switching conditions and topology is achieved by empirical test. Therefore, throughout this paper, it is proposed a design method of DBD power supply to guarantee a maximum ozone yield rate in accordance with DBD reactor modification and impedance variation when rapid gas discharging in the DBD reactor is proceeded.