• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.117-120
• /
• 1998

This paper proposes a new high efficiency single-phase AC-DC boost converter for power factor correction. Lossless commutation circuit is interposed in the proposed converter for soft-switching. Due to this commutation circuit, the converter operates in 9 mode. In spite of changing input voltage and load, It attracts a constant DC output voltage because of the PWM control scheme using both the output voltage feedback and the input voltage feedforward. The converter is suitable for high power applications and operates in continuous conduction mode. In this paper, a 2.4[kW] converter is designed and simulated.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.7 s.337
• /
• pp.27-34
• /
• 2005

Iterative detection (ID) has proven to be a near-optimal solution for concatenated Finite State Machines (FSMs) with interleavers over an additive white Gaussian noise (AWGN) channel. When perfect channel state information (CSI) is not available at the receiver, an adaptive ID (AID) scheme is required to deal with the unknown, and possibly time-varying parameters. The basic building block for ID or AID is the soft-input soft-output (SISO) or adaptive SISO (A-SISO) module. In this paper, Reduced State SISO (RS-SISO) algorithms have been applied for complexity reduction of the A-SISO module. We show that serially concatenated CPM (SCCPM) with AID has turbo-like performance over fading ISI channels and also RS-A-SISO systems have large iteration gains. Various design options for RS-A-SISO algorithms are evaluated. Recently developed density evolution technique is used to analyze RS-A-SISO algorithms. We show that density evolution technique that is usually used for AWGN systems is also a good analysis tool for RS-A-SISO systems over frequency-selective fading channels.

• ETRI Journal
• /
• v.31 no.3
• /
• pp.298-303
• /
• 2009

A single-switch parallel resonant converter for induction heating is implemented. The circuit consists of an input LC-filter, a bridge rectifier, and a controlled power switch. The switch operates in soft commutation mode and serves as a high frequency generator. The output power is controlled via the switching frequency. A steady state analysis of the converter operation is presented. A closed-loop circuit model is also presented, and the experimental results are compared with the simulation results.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.297-300
• /
• 2001

The SMZ half-bridge converter uses the resonance between the inductance of transformer and the resonant capacitances to transfer the input power to the load. In addition to this kind of characteristic of the converter, there are some features such as the capability of soft switching operation, a lower switching loss, and a higher power density in the converter. However in the low-voltage and high-output current applications of the converter, the extremely increased output ripple voltage prevents the converter from normal operation. In order to overcome the drawback of the converter, adding the output filter inductor to the converter, the converter shows the completely different resonant characteristics. In this paper, We analyzed the resonant characteristics of the SMZ converter with the output filter inductor and investigated what the analyzed results affect the converter operation. The experiment of a I50W prototype SMZ converter with 5V output and 310V input is carried out to verity the validity of the analyzed results.

• Journal of Power Electronics
• /
• v.12 no.4
• /
• pp.643-653
• /
• 2012

An interleaved DC/DC converter with series-connected transformers is presented to implement the features of zero voltage switching (ZVS), load current sharing and ripple current reduction. The proposed converter includes two half-bridge converter cells connected in series to reduce the voltage stress of the switches at one-half of the input voltage. The output sides of the two converter cells with interleaved pulse-width modulation are connected in parallel to reduce the ripple current at the output capacitor and to achieve load current sharing. Therefore, the size of the output chokes and the capacitor can be reduced. The output capacitances of the MOSFETs and the resonant inductances are resonant at the transition instant to achieve ZVS turn-on. In addition, the switching losses on the power switches are reduced. Finally, experiments on a laboratory prototype (24V/40A) are provided to demonstrate the performance of the proposed converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.6
• /
• pp.515-522
• /
• 2013

In this paper, a new PCS is proposed which is consisted of high boost dual converter and single phase half-bridge inverter. The proposed PCS is configured in parallel input / serial output, using two interleaved voltage doubler converter. Converter of the proposed PCS is distribute input current by configuring parallel input and reduced turn ratio of transformer by configuring serial output. Also, compositions of the inverter are composed of serial output capacitor of converter and half-bridge inverter. The dual converter and single phase half-bridge inverter is designed and characteristic of the new PCS is analysed. The system of the 1.5[kW] PCS is verified through an experimental about operation and stability.

• Journal of Power Electronics
• /
• v.17 no.6
• /
• pp.1433-1444
• /
• 2017

A family of non-isolated DC-DC three-port converters (TPCs) that allows for a more flexible power flow among a renewable energy source, an energy storage device and a current-reversible DC bus is introduced. Most of the reported non-isolated topologies in this area consider only a power consuming load. However, for applications such as hybrid-electric vehicle braking systems and DC microgrids, the load power generating capability should also be considered. The proposed three-port family consists of one unidirectional port and two bi-directional ports. Hence, they are well-suited for photovoltaic (PV)-battery-DC bus systems from the power flow viewpoint. Three-port converters are derived by combining different commonly known power converters in an integrated manner while considering the voltage polarity, voltage levels among the ports and the overall voltage conversion ratio. The derived converter topologies are able to allow for seven different modes of operation among the sources and load. A three-port converter which integrates a boost converter with a buck converter is used as a design example. Extensions of these topologies by combining the soft-switching technique with the proposed design example are also presented. Experiment results are given to verify the proposed three-port converter family and its analysis.

• International Area Studies Review
• /
• v.14 no.3
• /
• pp.109-130
• /
• 2010

The service sector comprises two thirds of world GDP in 2005 and takes 20% of the world trade. As the technologies such as telecommunication technologies advance, the long-distance trades in services is expected to increase. But there are few empirical research on the flows of services between regions. This paper studies the pattern of flows of long-distance trades in services across the regions. Since it is very hard to collect reliable data on long-distance trade in services, we collect data from regional input-output tables of Korea. The results shows that the hard service which can be consumed spatially separated from production tends to have more long-distance trade than the soft service which is consumed simultaneously with production. It also shows that regional gross domestic production is important factor for the pattern of trades in services.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1998.06a
• /
• pp.423-425
• /
• 1998

An optical system which can autonomously form and display an impression of a picture made up by many figures has been developed. This system consists of optical fuzzy-neurons which calculate the correlation between the input picture and the reference image by incoherent optics. The calculated signal is applied to an amplifier whereby the output signal increases, then decreases according to increase of the input signal . These outputs are synthesized, and are used for changing the position where the system gaze on a part of the input picture by light beam. In this system, the light intensity used for gazing changes chaotically, The attractor drawn from the change of light intensity corresponds to the impression of the picture. This paper shows the results that are calculated by the numerical simulation. The system has been simulated to express the impression for a picture formed by 4figures.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.5
• /
• pp.27-35
• /
• 2000

This paper deals with a control strategy for constant output power of SSRT(Soft Switching Resonant Type) FB(Full Bridge) DC-DC converter by an improved phase shift controller. When the FB DC-DC converter for the high density and the high effect control is operated in high speed switching, the switching loss and switching stress of the switching devices are increased. So, the soft switching method, which has the phase shift control with the digital I-PD controller, must be use in order to reduce its. And the output voltage that controlled by the digital I-PD controller tracks a reference without steady state error in variable input voltage. The validity of control strategy that proposed is verified from simulation results and experimental results by the DSP(TMS320C32).