• 한국해양공학회지
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• 제23권4호
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• pp.47-51
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• 2009

Thrust is one of the important performance characteristics of an AUV. At the design stage, the resistance of an AUV at its maximum speed is estimated and then the thrust system is designed, including the propeller diameter, propeller rpm, driving system, and required power. However, it is not possible to be certain that the thrust system has been correctly designed until the AUV is launched and its speed is measured. If data from a propeller open-water test is available, the thrust and torque of the propeller at a certain speed can be estimated. In addition, if the motor's torque characteristics are available, the maximum speed saturated by the induced propeller torque can be estimated. In this paper, an easy technique for estimating the maximum speed of an AUV will be shown, even in a case where additional resistance is gained from appendages not considered at the design stage. Furthermore, the thrust performance changes by adjusting the diameter of the propeller can be easily investigated.

• 한국정보통신학회논문지
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• 제2권2호
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• pp.231-239
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• 1998

본 논문에서는 영구자석형 동기전동기의 속도제어를 위한 전류제어 서보시스템을 설계하였다. PI(Proportional Integral) 제어기 파라메터의 자동동조(auto-tuning)를 위한 기존의 방법들에서는 출력응답이 지연되고 오버슈트 가 발생된다. 본 논문에서는 이러한 기존의 문제점들을 해결함으로써 빠른 응답과 오버슈트를 제거할 수 있는 새로운 PI자동동조 방법을 속도 제어기에 적용한다. 영구자석형 동기전동기 서보시스템은 수많은 서보 모터들이 사용되고 있는 자동화 공장에서 보수 유지의 용이성과 가제어성으로 인해 많은 장점들을 제공한다. 구현된 서보시스템은 회전자의 절대 위치 검출회로, 자동동조 PI 제어 알고리즘, DSP(Digital Signal Processor)에 의한 속도제어기, 그리고 전력 구동부 등으로 구성된다. 본 논문에서 제안된 서보시스템의 실질적인 유용성은 실험을 통해 입증한다.

• Journal of Power Electronics
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• 제5권3호
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• pp.198-205
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• 2005

The mechanical system of a drive can often be modeled as a two- or three-mass-system. The load is coupled to the driving motor by a shaft able to perform torsion oscillations. For the automatic tuning of the control, it is necessary to know the mathematical description of the system and the corresponding parameters. As the manpower and setup-time necessary during the commissioning of electrical drives are major cost factors, the development of self-operating identification strategies is a task worth pursuing. This paper presents an identification method which can be utilized for the assisted commissioning of electrical drives. The shaft assembly can be approximated as a two-mass non-rigid mechanical system with four parameters that have to be identified. The mathematical background for an identification procedure is developed and some important implementation issues are addressed. In order to avoid the excitation of the system with its natural resonance frequency, the frequency response can be obtained by exciting the system with a Pseudo Random Binary Signal (PRBS) and using the cross correlation function (CCF) and the auto correlation function (ACF). The reference torque is used as stimulation and the response is the mechanical speed. To determine the parameters, especially in advanced control schemes, a numerical algorithm with excellent convergence characteristics has also been used that can be implemented together with the proposed measurement procedure in order to assist the drive commissioning or to achieve an automatic setting of the control parameters. Simulations and experiments validate the efficiency and reliability of the identification procedure.

• 한국산학기술학회논문지
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• 제9권6호
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• pp.1529-1534
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• 2008

최근, 교반기는 화학물질의 교반 및 탈포를 위해 디스플레이, 반도체 업체에서 광범위하게 사용되고 있다. 교반기는 일반적으로 축, 교반조, 감속기어 및 구동 모터로 구성되어 있다. 교반기 설계시의 주요 사항은 회전시의 동적 특성을 평가하는 것이다. 회전시의 동적특성은 진동, 소음 및 열방출로 나타난다. 본 논문은 고속 교반기의 동적 특성을 실험적으로 규명하였다. 진동을 유발하는 주 인자는 회전체의 불균형에 기인한 것임을 알 수 있었으며, 교반 용기 부위의 온도가 전체온도에서 상대적으로 제일 높음을 알 수 있었다.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.852-857
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• 2011

조선업종은 숙련공의 감소와 노동력 부족을 해결하기 위해 자동화와 기계화가 필요하다. 특히 조선용 핸드레일 제조공정은 표준화된 타 분야와 달리 자동화가 낙후되어 있다. 본 연구에서는 조선용 핸드레일 제작에 사용할 수 있는 철의장 가공자동화시스템을 설계하고 개발하였다. 시스템의 기구부는 절단공정의 효율성, 생산성, 안정성 등을 고려하여 설계하였고, CATIA 와 ANSYS를 사용하여 구조물의 안정성을 확인하였다. 시스템 제어부는 개방성과 확장성을 제공하는 PCNC 콘트롤러를 사용하였고, 터치스크린 방식의 화면 조작을 통해 시스템의 제어 및 모니터링을 할 수 있도록 구축하였다. 개발된 철의장 가공자동화시스템은 수차의 구동테스트 및 가공테스트를 통해 성능의 우수성을 입증하여 실용단계에 있다.

• Journal of Power Electronics
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• 제13권3호
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• pp.419-428
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• 2013

The modular multilevel cascade converter (MMCC) is a new family of multilevel power converters with modular realization and a cascaded pattern for submodules. The MMCC family can be classified by basic configurations and submodule types. One member of this family, the Hexverter, is configured as Double-Delta Full-Bridge (DDFB). It is a novel multilevel AC/AC converter with direct power conversion and comparatively fewer required components. It is appropriate for connecting two three-phase systems with different frequencies and driving an AC motor directly from a utility grid. This paper presents the dq model of a Hexverter with both of its AC systems by state-space representation, which then simplifies the continuous time-varying model into a periodic discrete time-invariant one. Then a generalized multivariable optimal control strategy for regulating the Hexverter's independent currents is developed. The resulting control structure can be adapted to other MMCCs and is flexible enough to include other control criterion while guaranteeing the original controller performance. The modeling method and control design are verified by simulation results.

• 전력전자학회논문지
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• 제11권4호
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• pp.307-312
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• 2006

본 논문에서는 직류링크전류를 기반으로 SRM의 상전류를 추정하였고 이를 이용한 SRM 에 대한 속도제어법을 제안하였다. 또한 직류링크전류검출회로를 제안하여 전류검출분해능을 높일 수 있었으며 오프셋에 의한 영향을 최소화시킬 수 있는 장점을 가지고 있다. 상전류 정보를 이용한 SRM 구동방식과 직류링크전류정보를 이용한 SRM 구동방식을 실제실험을 통하여 비교함으로서 본 논문에서 제안한 상전류 추정알고리즘과 이에 관련된 직류링크전류 검출회로에 대한 유효성이 검증되었고 직류링크전류를 이용한 SRM 속도제어시스템은 속도응답이 3 상 전류정보를 이용한 시스템만큼 빠른 응답특성이 있음을 확인하였다.

• 한국안전학회지
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• 제29권1호
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• pp.7-14
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• 2014

Inverter module, which feeds the converted power to the traction motor for EMU. Consists of the power semiconductors with their gate drive unit(GDU)s and the control computer for driving, voltage, current and speed controls. Electrolytic condenser, connected to the gate drive unit and a core component to drive the power semiconductor, has problems such as reduction in lifetime and malfunction caused by electrical and mechanical characteristic changes from heat generation during high speed switching for generation of stable power. In this study, To check the service life of electrolytic condenser, the test was carried out in two ways. First, In the case of accelerated life testing of condenser, the Arrhenius model is a way of life testing. Another way is to analyze the reliability of the failure data by the method of parametric data analysis. Eventually, life time by accelerated life test than a method of failure data analysis(Weibull distribution) was found to be slightly larger output.

• Transactions on Electrical and Electronic Materials
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• 제9권5호
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• pp.181-185
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• 2008

Using the extensional vibration mode of PZT ring, a piezopump is successfully made. The PZT ring is polarized with thickness direction. The traveling extensional wave along the circumference of the ring is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic ring. The pump takes an unobtrusive operation into the simple displacing mechanism using peristaltic traveling waves without the physical moving parts. The finite elements analysis on the proposed pump model is carried out to verify its operation principle and design by the commercial FEM software. Components of piezopump were made, assembled, and tested to validate the concepts of the proposed pump and confirm the simulation results. The performance of the proposed piezopump is about 580 ${\mu}l/min$ in flow rate with the highest pressure level of 0.85 kPa, when the driving voltage is 150 $V_p$, 57 kHz.

• 한국정밀공학회지
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• 제33권12호
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• pp.965-970
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• 2016

Fuel used in the steel metallurgy industry is stored in huge stage systems called SILO. Fuel is released by RDM (Rotary Discharge Machine), at the place of utilization. RDM is located in the Silo, and is constituted of a main frame, driving part, discharging part and control part. RDM is combined to a direct motion on the rail in tunnel, having a rotary motion enabled by a motor. In this paper, we calculate the theoretical discharging capacity of RDM to confirm the correlation between design element and discharging capacity of RDM. Also, through structure analysis, we confirm the vulnerable point of RDM when it discharges the storage materials. We hope to apply these results to design a more efficient RDM.