• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.965_966
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• 2009

In this paper, a new soft-switching Two-switch Forward converter topology has been proposed. Compared with conventional two-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes, not only its duty cycle can exceed 0.5 to achieve wide range input voltage, but also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at $1/2V_{in}$, voltage stress across auxiliary switch can be clamped at $V_{in}$. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation $V_o=\frac{V_{in}(1-D}D{N}$. Therefore, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1015-1024
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• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• Journal of Communications and Networks
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• 제17권3호
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• pp.286-295
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• 2015

Avionic databuses fulfill a critical function in the connection and communication of aircraft components and functions such as flight-control, navigation, and monitoring. Ethernet-based avionic databuses have become the mainstream for large aircraft owning to their advantages of full-duplex communication with high bandwidth, low latency, low packet-loss, and low cost. As a new generation aviation network communication standard, avionics full-duplex switched ethernet (AFDX) adopted concepts from the telecom standard, asynchronous transfer mode (ATM). In this technology, the switches are the key devices influencing the overall performance. This paper reviews the avionic databus with emphasis on the switch architecture classifications. Based on a comparison, analysis, and discussion of the different switch architectures, we propose a new avionic switch design based on a time-division switch fabric for high flexibility and scalability. This also merges the design concept of space-partition switch fabric to achieve reliability and predictability. The new switch architecture, called space partitioned shared memory switch (SPSMS), isolates the memory space for each output port. This can reduce the competition for resources and avoid conflicts, decrease the packet forwarding latency through the switch, and reduce the packet loss rate. A simulation of the architecture with optimized network engineering tools (OPNET) confirms the efficiency and significant performance improvement over a classic shared memory switch, in terms of overall packet latency, queuing delay, and queue size.

• Journal of Power Electronics
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• 제15권2호
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• pp.497-503
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• 2015

This paper analyses the harmonic pollution to power grids caused by several high-power rectifiers, summarizes the requirements for rectifiers in suppressing grid-side current harmonics and optimizes a new-type of current source PWM rectifier with a hybrid switch. The rectifier with a hybrid switch boasts significant current characteristics and cost advantages in the high-power area. To further enhance the working frequency of the current source rectifier with a hybrid switch for suppressing grid-side harmonics and reducing the inductance size, this paper proposes an optimal control strategy based on space vector. It also verifies that the optimal control strategy based on space vector can reduce the total harmonic distortion of the grid-side current of the rectifier with a hybrid switch via circuit simulation and experimental results.

• 인터넷정보학회논문지
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• 제7권6호
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• pp.113-121
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• 2006

스위치 비용을 감소시킬 연구의 일환으로 공유형 광 지연 선로 버퍼를 갖는 광 패킷 스위치에서 인터넷 트래픽과 같은 비동기 가변길이 패킷들의 경합 해결을 위해 요구 되어지는 최적화된 튜닝 가능한 파장 변환기의 개수와 내부 파장 개수가 도출 되어 진다. 광 패킷 스위치 디자인 비용에 관련된 튜닝 가능한 파장 변환기의 개수와 내부 파장 개수를 도출하기 위해 스위치 내부에 한정된 수의 파장 변환기와 내부 파장을 고려해 주는 새로운 형태의 스케줄링 알고리즘을 제안하였다. 세 가지 튜닝 가능한 파장 변환기 구조들에 대해서 최소의 패킷 로스를 보장해 주는 최적화된 파장 변환기의 개수와 내부의 파장 개수가 자원 낭비를 예방해 주기 위해 평가되어졌다. 하나의 주어진 로드 하에서 파장 변환기 개수와 내부의 파장 개수가 의미 신장하게 감소되어 질 수 있었으며 또한 파장 변환기의 수와 내부 파장의 수를 완전히 갖는 광 패킷 스위치의 성능과 같은 패킷 손실 확률을 보장해 주었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.14-16
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• 2005

In this paper, a new control scheme to use 6-switch inverters for 3-phase switched reluctance motors (SRM) is proposed. Compared with the conventional asymmetric converter topology, it can minimize the entire system size and cost and can increase the efficiency. Therefore, it may have a new topology for SRM to compete the other ac motors, such as induction motors, brushless dc motors, and soon. The validity of the proposed method is verified by simulation, and experimental results.

• ETRI Journal
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• 제33권1호
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• pp.136-139
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• 2011

A modular upgrade design for packet transport switch nodes is presented where packet loss is dramatically reduced by intra-module and inter-module buffer sharing. This modular design offers significant cost and power reduction in a high-data-rate system where buffers are highly costly and power-greedy.

• Journal of Power Electronics
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• 제9권5호
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• pp.772-780
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• 2009

A novel soft-switching two-switch flyback converter is proposed in this paper. This converter is composed of two active power switches, a flyback transformer, a blocking diode, and two passive regenerative clamping circuits. The proposed converter has the advantages of a low cost circuit configuration, a simple control scheme, a high efficiency, and a wide operating range. The circuit topology, analysis, design considerations, and experimental results of the new flyback converter are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.723-727
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• 2004

A new high-performance and low cost single switch energy recovery display driver for an AC plasma display panel (PDP) is proposed. Since it is composed of only one auxiliary power switch, two small inductors, and eight diodes compared with the conventional circuit consisting of four auxiliary power switches, two small inductors, eight power diodes, and two external capacitors, it features a much simpler structure and lower cost. Nevertheless, since the rootmean-square (RMS) value of the inductor current is very small, it also has very desirable advantages such as n low conduction loss and high efficiency. Furthermore, there are no serious voltage-drops caused by the large gas-discharge current with the aid of the discharge current compensation, which can also greatly reduce the current flowing through power switches and maintain the panel to light at n lower sustaining voltage. In addition, all main power switches are turned on under the zero-voltage switching (ZVS) and thus, the proposed circuit has a improved EMI, increased reliability, and high efficiency. Therefore, the proposed circuit will be well suited to the wall hanging PDP TV. To confirm the validity of the proposed circuit, circuit operations, features,and design considerations are presented and verified experimentally on a 6-inch PDP, 50kHz-switching frequency, and sustaining voltage 141V based prototype.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.354-356
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• 2004

This paper is the transient analysis for choosing the optimal SCR ratings of AC3 utilization category testing equipment(AC3 TE) used for electrical durability test for magnetic switch according to IEC60947-4 Annex B by utilizing EMTP -ATPDraw. Magnetic contactor closes and opens the motor load with ON/OFF switch of electronic contactor. It is also used for protecting and controlling the load. Magnetic contactor detects the over-current flow in the load with a over-current relay and disconnects the load by opening its control power. The key cost of AC3 TE is the SCR ratings. The more decreases SCR ratings, the more decreased the cost is, but it is impossible to ensure the reliability. On the other hand, the more increases SCR ratings, the more increased the cost is. Thereupon, in this paper after the testing circuit is simulated by using EMTP-ATPDraw the SCR ratings will be applied in order to guarantee the testing reliability of PT&T(Power Testing and Technology institute in LG Industrial Systems Co.,Ltd.).