• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.67-68
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• 2015

본 논문은 폐루프 고피나스 자속관측기의 P/PI모드를 전환하여 전환점부근 저속에서 모터상수 변동에도 강인한 센서리스 벡터제어가 가능한 전환기법을 제안하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.37-42
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• 2004

This paper presents an optimal and robust tuning method of decentralized PI controller for the TITO second order systems to be formulated as LQR. The procedure is developed by establishing relationships between the closed-loop state equation including the decentralized PI tuning parameter and the . closed-loop state equation of LQR and by selecting the weighting factors Q and R of the cost function in order to satisfy the design specifications In frequency domain which the stability robustness and satisfied the performance guaranteed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.694-699
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• 2007

We consider an optimal antenna weighting scheme for a closed-loop transmit antenna diversity system in Rayleigh fading channels. We derive a closed-form expression for the optimal transmitter weights that minimize the average bit error rate (BER) subject to fixed average and peak transmit power constraints. It is shown that the peak power limitation degrades the average BER performance more significantly as the available average power and/or the number of transmit antennas increase.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.241-248
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• 1995

본 연구에서 얻어진 주된 결과를 요약하면 다음과 같다. 1) 모달필터의 오차로 인해 모달상태 추정에 오차가 발생할 때, 폐루프 진동제어계가 Lyapunov 점근 안정성을 갖기 위한 필요충분 조건식(26)을 유도하였다. 2) 모달필터의 오차가 클수록 폐루프 진동제어계의 안정성은 점점 나빠지게 된다. 3) 모달필터의 오차 .DELTA.D가 존재할 때, L$_{\infty}$-놈 이론을 적용하여 진동제어 응답성능의 오차의 상한, 식(32)를 유도하였다. 4) 응답성능 오차의 상한은 모달필터 오차 .DELTA.D의 크기에 비례하고 있으며, 비례계수는 모달공간에서의 제어기법이 종류에 따라 다르다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9C
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• pp.1252-1257
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• 2004

This paper presents a decentralized LQ-PID controller for the TITO system which satisfies the performance of good command following, disturbance rejection, and sensor noise reduction that is design specifications in the frequency domain The procedure is developed by establishing the relationship between the closed-loop state equations including the decentralized PID tuning parameters and the closed-loop state equations of LQR and by selecting the weighting factors Q and R of the cost function in order to satisfy the design specifications in the frequency domain.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.707-712
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• 1998

본 논문에서는 선형 시불변 시스템에 대해 상태되먹임을 이용한 폐루프계의 지정된 영역내의 극배치법을 제안한다. 본 제안된 기법은 해밀톤 행렬의 하중행렬 Q의 설정에 의해 지정된 영역 (α중심, γ반경)내에 극배치가 가능함을 보인다. 먼저, Gershgorin의 이론을 적용하기 위해 해밀톤 행렬을 등가 변환시킨 후 행렬의 각 계수를 α와 γ의 관계를 이용하여 유도한다. 위의 관계를 만족하는 해밀톤 행렬의 각 하중행렬과 변환행렬을 이용하여 폐루프계의 상태되먹임 제어칙을 구한다. 또한 본 기법은 해밀톤 행렬과 최적제어와의 관계를 지니고 있으므로 얻어진 폐루프계는 최적제어법에서와 동일한 강인함을 가지게 된다. 끝으로 예제를 통하여 지정된 영역내의 극배치가 이루어짐을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.1-8
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• 2004

This paper proposes an LQ-PID controller to reduce errors occurring between input and output speeds in braking or emergency braking and to solve delay of speed or the excessive overshoot problems occurring at the speed control of induction motor. The conventional LQ controller is a method that move the poles in locations that satisfy design specifications such as overshoot and settling time etc. by state-feedback. So it may not be able to satisfy the overshoot requirement in case of the existence of zero in the closed loop transfer function. To attack this zero-problem it is presented a new design methodology of LQ-PID controller by introducing an analytic technique to eliminate the effect of zeros on the closed loop transfer function.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.601-609
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• 2000

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. However, DTC do not show good performance at low speed range with conventional open loop stator flux observer when stator resistance varied. Therefore, authors propose a new nonlinear stator flux observer in order to estimate the stator flux of induction motor at low speed and show its simulation results.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.370-373
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• 2010

본 논문에서는 유도전동기와 제어기의 폐루프 극점을 원하는 위치에 배치하여 유도전동기를 위한 PID제어 동조파라미터를 얻어 유도전동기를 제어하는 방법을 제안한다. 이러한 설계방법은, 설계요건뿐만 아니라 제어기 고유의 안정도와 강인성까지 제공하므로 매우 유용하다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.853-861
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• 2012

This paper considers one of the explicit guidance algorithms, which has been proposed by Jaggers, to determine the closed-loop guidance algorithm for upper stages of a 3-staged space launch vehicle. Its commanded thrust vector is closer to the optimal solution when compared with that obtained by using the well-known Powered Explicit Guidance (PEG), which has been developed through the Space Shuttle program. Its performance is evaluated here by applying for guidance of the launcher during the second and third stages. Furthermore, to generate more precise guidance commands, it is attempted not to use the approximate formulas for the derivation of the original guidance law, and it is shown that performance is improved in comparison with the original.