• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.379-380
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• 2016

본 논문에서는 Z-소스 네트워크 기반의 배터리 시뮬레이터의 전압 제어기 설계를 위한 소신호 모델링을 수행하고 보드선도를 이용한 안정도 분석을 통한 전압 제어기 설계 방법을 제안하였다. 이를 통하여 인덕턴스와 커패시턴스에 따라 변하게 되는 시스템의 주파수 응답 특성을 고려하여 Z-소스 네트워크 기반의 배터리 시뮬레이터가 안정적으로 동작하도록 하는 전압 제어기의 제어 이득값을 선정하였다. 제안한 방법은 MATLAB을 이용한 안정도 분석을 통하여 검증되었다.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.509-510
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• 2016

본 논문은 계통연계형 인버터의 위상추종기법인 SRF-PLL을 모델링하고, FPGA에 구현하기 위해 System Generator를 이용하여 설계하였다. SRF-PLL의 비례-적분 이득은 소신호 해석을 하여 일반화를 통해 입력전압의 크기에 관계없이 적용가능하며, 주파수 응답에서 65도 위상여유를 갖는 안정한 이득을 산정하였다. FPGA 구현을 위해 MATLAB/SIMULINK와 연동 가능한 System Generator를 이용하여 SRF-PLL을 모델링하였으며, MATLAB 기반의 시뮬레이션과 실험을 통하여 위상추종 특성을 분석하였다.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.177-180
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• 2003

본 논문에서는 dc-dc convertor의 진단을 위해 buck 컨버터의 등가 모델을 가정하고 주요 파라메터를 시스템 식별 기법을 통해 추정하였으며 추정된 결과가 실제 시스템의 특성을 충실히 반영하는지를 계측기를 통한 주파수 응답 측정 결과와 비교하여 검증하였다. dc-dc 컨버터의 모델 파라메터 추정을 통해 주요 진단지수를 계산할 수 있으며 진단 지수를 이용하여 시스템의 열화 여부를 판단할 수 있음을 확인 하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.351-356
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• 2001

In this paper, a general one-loop control system was assumed as a model system which has a time-delay element connected with a first order-lag element in series. After the corresponding parameter set causing stability limit condition for the model system was obtained by mathematical procedures, their loci on the parameter space was taken according of frequency change,. The parameter set loci of stability limit showed a specific pattern, and particularly the curves on the Kp-Ti parameter space were able to generalized in the form of an exponential formula. These properties were also compared with the results taken from experimental procedures by Nyquist response method and Ziegler & Nichols method on the time domain, and both results were confirmed to be nearly same.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.539-544
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• 2004

This paper discusses the measurement of tire driving performance for 2 types of tire model. Tire is almost composed of rubber, and this is related with the bearing capacity of tire due to the external force. In this study, an explicit time integration method has been used to simulate steady state rolling along a straight path and over a cleat. And analysis for tire dynamic response rolling over a cleat is importnat to study automobile NVH properties. Besides, the evaluation of contact shear force is perfomed for steady state rolling and braking state. The results show that there are noticeable differences between 205/60R15 and 225/60R15 tire model.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.227-236
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• 2002

We have performed two kinds of experimental modal analyses fur a radial tire for passenger car under free-suspension. One is the modal analysis to obtain three-dimensional modes of tire using accelerometers and the other is the one to identify cavity resonance frequency using a pressure sensor. From the first analysis, we have obtained the three-dimensional natural modes, which makes it possible to grasp the features of the modes and to classify the vibrational modes into symmetric, non-symmetric, and antisymmetric modes in a simple way by using the experimental results. From the first and the second experimental analyses we have identified the cavity resonance frequency and its three-dimensional mode shape.

• Journal of KSNVE
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• v.10 no.3
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• pp.500-507
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• 2000

Dynamic forces due to mechanical and hydraulic related causes are always exerted on operating turbomachinery such as centrifugal pumps. To ensure the safety and the reliability of the pump. the magnitudes of the vibration must be kept within an acceptable limit. The focus of this paper is on the identification of the vibration behavior and the quantitative analysis of the hydraulic excitation forces. As the structure becomes more complex finite element analysis is essential to accurately predict the vibration characteristics and the excitation forces, This paper presents an experimental and analytical technique to find and solve to vibration problems in double volute double suction centrifugal pump. Measured vibration data due to the dynamic forces are presented and individual causes are identified, finally excitation forces of the pump are inversely estimated at each frequency on operating conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.385-386
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• 2008

Dynamic stability of the vehicle rearview mirror is an important factor for the driver's visual perception (image blur) when driving down the road and regarded as one of the vehicle level N&V performance of visible component vibration. Several projects within GM identified a set of objective metrics and validation methods that can replace current existing subjective evaluation of mirror stability. This paper presents objective evaluation results for assessing dynamic stability (angle of rotation) of the vehicle rearview mirrors using both in-lab FRF measurements and on-road testing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.943-946
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• 2007

The vibration and noise characteristic of the Axial-gap motor for an air conditioner were analyzed. Experimental Modal Analysis was performed to understand the vibration characteristic of the motor. The noise of motor was measured in a dead room. Finite Element Method was performed to find the vibration characteristic of the motor by using ABAQUS program.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1087-1090
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• 2005

In precision machinery systems for medical and chemical applications, micropumps with a low pulsation have been demanded and investigated for accurate delivery of a small amount of liquid. This study proposes sheet type check valves instead of ball type check valves for PZT pumps and performs some tests on dynamics characteristics of check valves having different design parameter with variable frequency. The selected materials of check valves is NBR, PP film, Polyimide and Stainless steel(SUS304). In the experiment, dynamic characteristics of stainless steel thin plate have better performance than others.