• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.149-152
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• 2001

본 논문은 연속 시간과 이산 시간에서의 스위칭 모드 퍼지 모델 기반 제어기의 새로운 설계 기법에 대해서 논의한다. 스위칭 모드 퍼지 모델 기반 제어기의 설계에는 Takagi-Sugeno(75) 퍼지 시스템이 사용된다. 이 스위칭 모드 퍼지 모델 기반 제어기는 "정복-분할(divide and conquer)"이라는 하향식 접근 방식을 이용한다. 이 방법은 여러 개의 규칙을 가지고 있는 시스템에서 유한의 하위 시스템으로 시스템을 분할하여 각각의 부분 해를 구하고 이들을 결합하여 전체 시스템의 해를 구하는 방법이다. 제어기의 설계 조건은 주어진 75 퍼지 시스템의 안정화를 보장하는 선형 행렬 부등식들(LMls)에 의해 결정된다. 적절한 시뮬레이션 예제를 통한 성능 비교를 통해 본 논문의 우수성을 입증한다.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.121-122
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• 2014

멀티 레벨 인버터는 높은 출력 전압을 갖으며, 낮은 THD(Total harmonic distortion)를 요구하는 시스템에 적합하다. 그 중 cascaded H-brige 멀티레벨 인버터는 H-bridge 셀별 관리가 쉽고, 레벨 수를 증가시키기 쉽다는 장점 때문에 많이 이용되어 왔다. 본 논문에서는 cascaded H-bridge 인버터의 기존 PI (proportional integral) 제어 기반 PWM (pulse width modulation)기법의 스위칭 패턴과 모델 예측 제어의 스위칭 패턴을 비교하고 모델예측 제어 시 셀 별 스위칭 패턴 균형을 위한 방법을 제안한다.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.199-200
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• 2014

본 논문은 3상 인터리브드 양방향 DC-DC 컨버터를 다룬다. 전류 리플을 줄이기 위해 3상 인터리브드 방식을 이용하였으며 소프트 스위칭 조건을 확보하기 위해 DCM으로 동작한다. DCM동작시 발생할 수 있는 스위칭 노이즈를 저감하기 위하여 새로운 스위칭 기법을 제안하고 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.165-173
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• 2007

This paper introduces a new current sharing technique to Interleaved Boost Converter (IBC) using carrier slope control. The IBC is able to boost the input voltage and operates at higher current levels and has various advantages over a single power module. However, how to balance the current each module is still important problem. To solve this problem, the proposed technique can distribute the power and load current equally based on master-slave current sharing method. Unlike a conventional approach, this technique can be extended even though the current stress of switching components at slave modules is significantly smaller than that of the master module. The simulation and the experimental results are presented to show the validity.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.6
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• pp.44-50
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• 2002

A novel technique for minimization of simultaneous switching noise is Presented. Dual Layer Power Line (DLPL) structure i:; newly proposed for a possible silicon realization of a mutual inductor, with which an instant large current in the power line is half-divided flowing through two different, but closely coupled, layers in opposite directions. This mutual inductance between two power layers enables us to significantly reduce the switching noise. SPICE simulations show that with a mutual coupling coefficient higher than 0.8, the switching noise reduces by 63% compared to the previously reported solutions. This DLPL technique can also be applied to PCB artworks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.514-524
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• 2005

In optical burst switching(OBS) networks, the ingress edge router assembles packets in the same class queue into the appropriate size of burst. A burst control packet(BCP) is generated for channel reservation of corresponding data burst and sent earlier than the corresponding data burst with an offset time. Offset time is determined considering the number of hops from source to destination and the required quality of service(QoS). After offset time, the burst data is passed through tile pre-configured optical switches without any O/E/O conversion. But a failure in OBS networks may lead to the loss of bursts until the ingress nodes receive the failure indication signal. This results in a significant degradation in QoS. Therefore, in this paper, we propose a fault-tolerant node architecture based on sub-carrier multiplexing to reduce the effects of failure in OBS networks. The Performance of the proposed fault-tolerant node architecture exhibits considerable improvement as compared with the previous ones.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.19-25
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• 2008

In this paper, author proposes a novel step-up AC-DC chopper operated with power factor correction(PFC) and with high efficiency. The proposed chopper behaves with discontinuous current control(DCC) of input current. The input current waveform in the proposed chopper is got to be a discontinuous sinusoid form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity and the control method is simple. In the general DCC chopper, the switching devices are turned-on with the zero current switching, but turn-off of the switching devices is switched at current maximum value. To achieve a soft switching of the switching rum-off, the proposed chopper is used a new partial resonant circuit. The result is that the switching loss is very low and the efficiency of chopper is high.

• Journal of IKEEE
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• v.24 no.1
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• pp.19-24
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• 2020

This paper presents a 3-level, 2-level SVPWM technique with 100 kHz switching using Verilog HDL, one of the languages of FPGA. In the case of IGBT devices mainly used in inverters, they have a switching frequency around 20kHz. Recent research and development of next-generation power semiconductor devices such as GAN has enabled switching of more than 100kHz, which can miniaturize power converters, and apply various new algorithms due to the injection of harmonics. In the existing system using the IGBT, the control using the DSP is common, but the controller configuration for 100 kHz switching requires the use of FPGA. Therefore, this paper explains the theory and implementation of SVPWM applied to two-level and three-level inverters using FPGAs and verifies the performance through the output waveform. In addition, this paper implements 3-level SVPWM by using only one carrier instead of using two carriers in the conventional method.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.301-302
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• 2016

Hold-up time 조건에 의해 넓은 입력전압 범위에서 설계되는 하프-브리지 LLC 컨버터는 높은 전압 이득을 얻기 위해 작은 자화 인덕턴스와 넓은 스위칭 주파수 범위가 요구된다. 하지만 이는 큰 1차측 도통손실 및 코어 손실을 초래한다. 본 논문에서는 하프-브리지 LLC 컨버터가 좁은 입력전압에서 설계되기 위한 새로운 hold-up time 보상 기법을 제안한다. 따라서 제안된 기법에서의 하프-브리지 LLC 컨버터는 큰 자화 인덕턴스 및 좁은 스위칭 주파수 범위로 설계 될 수 있다. 제안된 회로의 효과는 90-264Vrms 입력, 250-400V 링크 전압, 48V/480W 출력을 갖는 prototype의 실험을 통해 검증된다.

• Journal of KSNVE
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• v.7 no.2
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• pp.273-279
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• 1997

Reduction of number of actuators for independent modal space control In this paper, a new modified independent modal space control (IMSC), which relaxes the fundamental hardware limitation of IMSC, is suggested to handle the vibration and attitude control problem for flexible large structures. This method has adapted a new switching algorithm between controlled modes and a novel design technique for modal control force. The main advantage of this method is to minimize the discontinuity of the modal control forces and to assure the asymptotic stability of the closed-loop systems. This process is shown to be simple and efficient in a realistic example of vibration control of a cantiloever beam. It has been found that the modified IMSC suggested in this paper, which can reduce the number of actuators, is highly excellent compared to other previous methods in terms of the performance and stability of the vibration control systems.