• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.56-62
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• 2004

We present a multi-Gbit/s digital I/O interface based on RF-modulation and capacitive-coupling over an impedance matched transmission line. The RF-interconnect(RFI) can greatly reduce the digital switching noise and eliminate the dc power dissipation over the channel. It also enables reduced signal amplitude(as low as 200 ㎷) with enhanced data rate and affordable circuit overhead. This paper addresses the system advantages and implementation issues of RFI. A prototype on-chip RFI transceiver is implemented in 0.18-${\mu}{\textrm}{m}$ CMOS. It demonstrates a maximum data rate of 2.2 Gbit/s via 10.5-㎓ RF-modulation. The RFI can be very instrumental for future high-speed inter- and intra-ULSI data links.

• IE interfaces
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• v.12 no.2
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• pp.174-179
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• 1999

This paper describes the development of low cost, miniaturized multi-function image splitter for an unmanned guard system. The essential equipments of an image splitter system consist of a video system which displays in one screen images inputted by several cameras, a frame switcher which records each image sequentially in VTR, and TBC(Time Base Control) system which prevents image flickering during image switching. Currently, the price of similar system on the market is high, system management and repair are difficult, and bulky space is required. Futhermore, since currently available frame switcher can record only 30frame/sec, if eight cameras are installed, each camera image is recorded at the low speed of 3.75frame/sec, and consequently skip some images which may be vital for legal evidence. In this research, we have solved the problem of low speed recording by recording the video screen of splitted images at 30frame/sec and zooming each image when play back.

• Journal of Power Electronics
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• v.15 no.1
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• pp.96-105
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• 2015

In recent years, the multilevel converters have been given more attention due to their modularity, reliability, failure management and multi stepped output waveform with less total harmonic distortion. This paper presents a novel symmetric multilevel inverter topology with reduced switching components to generate a high quality stepped sinusoidal voltage waveform. The series and parallel combinations of switches in the proposed topology reduce the total number of conducting switches in each level of output voltages. In addition, a comparison between the proposed topology with another topology from the literature is presented. To verify the proposed topology, the computer based simulation model is developed using MATLAB/Simulink and experimentally with a prototype model results are then compared.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.240-241
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• 2017

멀티레벨 방식의 Dual Active Bridge 컨버터는 기존의 컨버터와 비교하여 높은 자유도의 스위칭 방식을 가진다. 본 논문에서는 멀티 레벨 방식의 DAB 컨버터의 동작원리를 분석하고, 인덕터 전류의 RMS 값과 THD를 최소화하기 위하여 기본파를 제외한 3 고조파와 5 고조파를 감쇄하는 스위칭 방식을 제안한다. 다양한 스위칭 패턴에 따른 인덕터 전류 RMS 값과 THD를 비교하여 제안하는 스위칭 방식의 타당성을 검증하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.422-428
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• 2013

Recently, we use a static synchronous compensator(STATCOM) with cascaded H-bride topologies, because it is easy to increase capacity and to reduce total harmonic distortion(THD). When we use equipment for reactive power compensation, dc-link voltage unbalances occur from several reasons although loads are balanced. In the past, switching pattern change of single phase inverter and reference voltage magnitude change of inverter equipped with power sensor have been used for dc-link voltage balance. But previous methods are more complicated and expensive because of additional component costs. Therefore, this paper explains reasons of dc-link voltage unbalance and proposes solution. This solution is complex method that is composed of reference voltage magnitude change of inverter without additional hardware and shifted phase angle of inverter reference voltages change. It proves possibility through 1000[KVA] system simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.158-159
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• 2007

In this paper a novel structure of multi-level converter for reducing ripple of output voltage is proposed. In the proposed converter Buck converters are connected in series to generate the output voltage and the ripple of output voltage can be reduced compared with the exiting Buck converter. Especially when outputting lower output voltage the number of acting switching elements is less and the result of ripple reducing is more obvious. It is expected that the converter proposed in this paper can be very useful in the case of wide range of output voltage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.686-689
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• 2014

This Paper is about the study that use the IPM(Intelligent Power Module) which is a integrated switching module to drive inverter gates for driving of a multi-pole BLDC(Brushless Direct Current) motors. When designing a inverter using the various manufacturers IPM, it suggests a electronic circuit system to evaluate the electrical and logical characteristics of the IPM with various brands.

• Journal of Power Electronics
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• v.19 no.2
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• pp.431-442
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• 2019

This paper proposes a unified high-frequency bipolar buck-boost (UHFBB) control strategy for a dual-active-bridge (DAB), which is derived from the classical buck and boost DC/DC converter. It can achieve optimized current stress of the switches and soft switching in wider range. The UHFBB control strategy includes multi-control-variables, which can be achieved according to an algorithm derived from an accurate mathematical model. The design method for the parameters, such as the transformer turns ratio and the inductance, are shown. The current stress of the switches is analyzed for selecting an optimal inductor. The analysis is verified by the experimental results within a 500W prototype.

• Coupled systems mechanics
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• v.10 no.6
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• pp.521-544
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• 2021

In this work, we present the development of a 3D lattice-type model at microscale based upon the Voronoi-cell representation of material microstructure. This model can capture the coupling between mechanic and electric fields with non-linear constitutive behavior for both. More precisely, for electric part we consider the ferroelectric constitutive behavior with the possibility of domain switching polarization, which can be handled in the same fashion as deformation theory of plasticity. For mechanics part, we introduce the constitutive model of plasticity with the Armstrong-Frederick kinematic hardening. This model is used to simulate a complete coupling of the chosen electric and mechanics behavior with a multiscale approach implemented within the same computational architecture.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.8
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• pp.25-32
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• 2011

Networks-on-chip (NoC) is emerging as a key technology to overcome severe bus traffics in ever-increasing complexity of the Multiprocessor systems-on-chip (MPSoC); however traditional electrical interconnection based NoC architecture would be faced with technical limits of bandwidth and power consumptions in the near future. In order to cope with these problems, a hybrid optical NoC architecture which use both electrical interconnects and optical interconnects together, has been widely investigated. In the hybrid optical NoCs, wormhole switching and simple deterministic X-Y routing are used for the electrical interconnections which is responsible for the setup of routing path and optical router to transmit optical data through optical interconnects. Optical NoC uses circuit switching method to send payload data by preset paths and routers. However, conventional hybrid optical NoC has a drawback that concurrent transmissions are not allowed. Therefore, performance improvement is limited. In this paper, we propose a new routing algorithm that uses circuit switching and adaptive algorithm for the electrical interconnections to transmit data using multiple paths simultaneously. We also propose an efficient method to prevent livelock problems. Experimental results show up to 60% throughput improvement compared to a hybrid optical NoC and 65% power reduction compared to an electrical NoC.