• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.168-169
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• 2017

본 논문에서는 ZCMV(zero common mode voltage) PWM을 사용하는 병렬형 3상 3레벨 NPC 컨버터의 DC단 전압의 불평형 제어를 이용한 순환전류 저감 알고리즘을 제안한다. 이상적으로 ZCMV PWM은 공통 모드 전압을 발생하지 않지만, 초기 운전 및 데드타임과 같은 실제적인 문제로 인해 공통 모드 전압이 발생한다. 발생한 공통 모드 전압은 미세한 순환전류를 발생시키며 이는 컨버터의 효율을 감소시킨다. 따라서, 본 논문에서는 DC단 전압 불평형 제어를 이용하여 순환전류를 저감하는 제어 알고리즘을 제안한다. 상, 하단 DC 전압의 불평형은 공통 모드 전압을 발생시키며 이를 통해 미세하게 발생한 순환전류를 저감하여 컨버터의 효율을 향상 시킬 수 있다. 제안한 알고리즘은 시뮬레이션을 통해 타당함을 검증하였다.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2992-2994
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• 1999

This paper investigates the direct adaptive control of nonlinear systems using RBFN(radial basis function networks). The structure of the controller consists of a fixed PD controller and a RBFN controller in parallel. An adaptation law for the weight adjustment is developed based on the Lyapunov stability theory to guarantee the stability of the overall control scheme. Also, the tracking errors between the system outputs and the desired outputs converge to zero asymptotically. To evaluate the performance of the controller, the proposed method is applied to the trajectory control of the two-link manipulator.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.139-142
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• 2009

Comparison of three converter topologies for single phase switched reluctance motor is proposed in this paper. Due to the limitation of do-link voltage, conventional asymmetric converter is difficult to build up enough phase current in the high speed operation. In order to solve this problem, boost converter is used to improve the performance. Two active boost converters are reviewed: one is series-connected type, another is parallel-connected. Otherwise, a novel active boost converter is proposed. The comparison of these converters is based on the voltage raring of capacitor, stability and converter topology. Because the converter selection depends on the motor design, the single phase 6/6 SRM is considered in this paper. Some simulations results are executed. And the results verified the analysis in this paper.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.847-849
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• 1993

Two new schemes of three-phase rectifier using softing switching methods are introduced for the input power factor correction. These three-phase rectifiers are employed the zero voltage switching for the parallel resonant and zero current switching for the series resonant AC link type rectifiers. The dynamic modeling and discontinuous integral cycle mode control technique are also presented. With the proposed circuits and control technique, the high power factor can be obtained.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.121-124
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• 1998

Front end AC to DC converters of the boost type are used in traction applications for generating the DC link for the inverters. A GTO based converter is usually switched with a switching frequency of 300 to 500Hz, resulting in low frequency harmonic problems. In order to avoid this, multiple converters with Phase shifted carrier waveforms are used to suppress the low frequency harmonics. A detailed study of an AC to DC converter, with two converters parallely operated with Phase shifted carrier wave farms is Presented in this paper.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.264-269
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• 2019

This paper presents mechanical design and control of a bio-inspired legged robot. To achieve a fast legged running mechanism, a novel linkage leg structure is designed based on hind legs of domestic cats. The skeletomuscular system and parallel leg movement of a cat are analyzed and applied to determine the link parameters. The hierarchical control architecture is designed according to the biological data to generate and modulate desired gaits. The effectiveness of the leg mechanism design and control is verified experimentally. The legged robot runs at a speed of 46 km/h, which is comparatively higher speed than other existing legged robots.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.637-638
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• 2014

This paper proposes a new visualization method based on Vitualization technique which uses internal relationship of user correlation and external information of social network to visualize user relationship hierarchy. The proposed method use hadoop on virtual machine of OpenStack for distribution and parallel processing which the result of calculation visualizes hierarchy graph to analyze link nodes of Social Network Services for users.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.382-383
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• 2019

본 논문에서는 고효율 및 비용 절감을 위한 컴프레서용 유도 전동기기반 DC/DC 컨버터 판단 알고리즘을 제안한다. 소형 커패시터를 사용한 인버터 시스템은 넓은 다이오드 전도 시간을 나타내며 불충분한 DC-Link 전압으로 발생하는 효율 감소를 해결하기 위하여 전력변환시스템의 판단 기법을 제안하고, 이에 대한 유효성을 시뮬레이션 해석을 통해 검증한다.

• Earthquakes and Structures
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• v.23 no.6
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• pp.535-547
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• 2022

Handball sport, as its name postulates, is a team sport which highly physical workout. During a handball play, several ball impacts are applied on the hands resulting vibration in the forearm, upper arm, shoulders and in general in whole body. Hand has important role in the handball's game. So, understanding about the dynamics and some issues that improve the stability of the hand is important in the sport engineering field. Ulna and radius are two parallel bones in lower arm of human hand which their ends are located in elbow and wrist joint. The type of the joint provides the capability of rotation of the lower arm. These two bones with their ends conditions in the joints constructs a 4-link frame. The ulna is slightly thinner than radius. So, understanding about hand kinematics in handball's game is an important thing in the engineering field. So, in the current work with the aid of a multi-physics simulation, dynamic stability analysis of the ulna and radius bones will be presented in detail.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.701-708
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• 1998

This paper presents a novel non-resonant PWM DC-DC converter for X-ray high-voltage power generator using the parasitic impedances of the high-voltage high-frequency link transformer with its output high-voltage control scheme and steady-state characteristics compared to the conventional series-parallel resonant DC-DC converter. The key point of this approach is to evaluate effectiveness of reduction of the turn ratio of the high-voltage high-frequency transformer on improvements in power conversion efficiency and the power factor applying a boost AC-DC converter as DC voltage source, especially in the long exposure term and light output load ranges.