• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2803-2806
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• 2003

In this paper considers the design of the effective controllers for the plant with an integrator and a long dead time. The structure of the new DTC(Dead Time Compensator) that has an additive filter is proposed. Our DTC shows the improved performance in set-point response and disturbance rejection. Especially the bad effect of the long dead time in the disturbance rejection is fairly reduced by using the additive filter. illustrative examples are provided to show the availability of the proposed controller.

• 한국전자파학회논문지
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• 제18권7호
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• pp.710-716
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• 2007

본 논문에서는 마이크로스트립 구조의 고조파 제거 회로를 이용하여 900 MHz 1 W 전력 증폭기 설계에 관하여 연구하였다. 기존의 전력 증폭기들에는 고조파 제거를 위하여 여러 단의 집중 정수 소자를 이용한 필터를 사용함으로써 회로의 크기가 커지고, 사용되는 마이크로스트림 선로의 경우 주파수의 반복적인 특성만을 나타냄으로써, 비선형 회로들의 출력에 존재하는 모든 고조파 성분들을 제거하지 못하는 단점을 개선한 것이다. 설계된 전력 증폭기는 구동 증폭단, 전력 증폭단 그리고 고조파 제거단으로 각각 구성하였고, 에폭시 기판에 하이브리드 형식으로 구현하였다. 구현된 전력 증폭기는 고조파 제거 회로를 부가하지 않았을 경우와 비교해서 24 dBc의 2차 고조파, 30 dBc의 3차 고조파의 감쇄 특성을 보였으며, 전력 증폭기와 안테나 사이의 출력단 필터를 대신할 수 있을 것으로 판단된다.

• 한국생산제조학회지
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• 제9권1호
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• pp.60-67
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• 2000

An improved disturbance rejection control scheme is presented for minimizing the position error due to the repeatable runout disturbances in high density disk drive systems The proposed control algorithm is capable of attenuating repeatable disturbances which is one of the major detractors to hard disk drive quality and performance. This is achieved by a sys-tematic combination of an optimal feedback component and a feedforward preview component. The feedback component is designed where the emphasis is placed on robustness. The feedforward component is on the basis of a preview control comprised of a measured disturbance signals which leads to better disturbance rejection capabilites. The designed con-troller is applied as a plug-in module to a high density hard disk drive with a pre-existing conventional servo controller. Simulations have been carried out to demonstrate the effectiveness of this control scheme in the reduction of the periodic disturbances.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.256-259
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• 2003

In this paper, a design of multi-layered BPF(bandpass filter) using LTCC(Low Temperature Co-fired Ceramic) process by a lumped-elements is proposed for SOP(system-on-a-chip) of wireless communication systems. The proposed BPF improved a characteristic of rejection band to build an attenuation pole caused by structurally adjacent co-inductance and coupling. The simulation data shows a bandwidth of 90MHz from a center frequency of 2.4GHz, a return loss of 27dB, an insertion loss of 3.2dB, and an attenuation of at least 20dBc at $f_0{\pm}250MHz$. Simulations have used serenade circuit simulation and HFSS EM simulation.

• 한국해양공학회지
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• 제38권3호
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• pp.115-123
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• 2024

USBL systems are essential for providing accurate positions of autonomous underwater vehicles (AUVs). On the other hand, the accuracy can be degraded by outliers because of the environmental conditions. A failure to address these outliers can significantly impact the reliability of underwater localization and navigation systems. This paper proposes a novel outlier rejection algorithm for AUV localization using Voronoi diagrams and query point calculation. The Voronoi diagram divides data space into Voronoi cells that center on ultra-short baseline (USBL) data, and the calculated query point determines if the corresponding USBL data is an inlier. This study conducted experiments acquiring GPS and USBL data simultaneously and optimized the algorithm empirically based on the acquired data. In addition, the proposed method was applied to a sensor fusion algorithm to verify its effectiveness, resulting in improved pose estimations. The proposed method can be applied to various sensor fusion algorithms as a preprocess and could be used for outlier rejection for other 2D-based location sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.515-517
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• 1999

This paper considers the design of the effective controllers for the plant with an integrator and a long deadtime. The structure of the new DTC(DeadTime Compensator) that has an additive filter is proposed. Our DTC shows the improved performance in set-point response and disturbance rejection. Especially the bad effect of the long deadtime in the disturbance rejection is fairly reduced by using the additive filter. Illustrative examples are provided to show the availability of the proposed controller.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.186-191
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• 2011

This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size ($14.6{\times}13.2{\times}0.76$ mm) and a low insertion loss when compared with conventional filters.

• Membrane and Water Treatment
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• 제9권6호
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• pp.385-392
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• 2018

Poly vinyl chloride (PVC) was chemically modified, and used for ultrafiltration to analyze the performance. Non-solvent induced phase separation (NIPS) method was used to prepare membranes. The neat PVC membrane was casted and used as a control membrane. Modified membrane was prepared by reacting PVC with ethanolamine (EA) in the casting solution (labeled as CM-PVC). Pure water permeability (PWP) was evaluated by measuring pure water flux. Humic acid was used as model foulant solute to analyze flux and rejection ability of membranes. Flux and rejection data of neat and modified membranes were compared to prove the improvement in the filtration performance. The experimental results showed that for PVC and CM-PVC, PWP was calculated to be ~64 and ${\sim}143L/m^2{\cdot}h$, respectively, and the rejection of humic acid was found to be 98% and 100%, respectively. TGA was carried out to analyze the effect of chemical modification on the thermal stability of polymer. FT-IR analysis was another characterization technique used for the comparative study.

• 한국산학기술학회논문지
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• 제6권1호
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• pp.37-47
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• 2005

본 논문은 외란 제거 제어기의 실제적인 설계와 구현방법을 제안한다. 2 DOF 구조에서는 외란 제거의 성능은 순 방향 루프 제어기의 고 이득 없이 개선될 수 있다. 그러나, 2 DOF의 설계 방법이 2 DOF 수학적인 이론에 근거하기 때문에 다양한 응용 분야의 사용이 쉽지 않았다. 외란 관측기(Disturbance Observer, DOB)는 간단하지만, 매우 효과적인 2 DOF 제어기이다. 이 논문에서 기본적인 DOB 특성부터 설계와 구현의 기술적인 방법까지 실제적인 문제를 다룬다. 또한 실질적인 방법에 의하여 모델링하는 방법과 그 예를 설명하였다. 제안한 방법은 두 가지의 선형 모터 시스템으로 유용함을 증명하였다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.272-283
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• 2017

In this paper, an improved predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) control system is proposed, on account of the standard PFC method cannot provides a satisfying disturbance rejection performance in the case of strong disturbances. The PFC-based method is first introduced in the control design of speed loop, since the good tracking and robustness properties of the PFC heavily depend on the accuracy of the internal model of the plant. However, in orthodox design of prediction model based control method, disturbances are not considered in the prediction model as well as the control design. A minimum-order observer (MOO) is introduced to estimate the disturbances, which structure is simple and can be realized at a low computational load. This paper adopted the MOO to observe the load torque, and the observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC strategy with torque compensation, called the PFC+MOO method, is presented. The validity of the proposed method was tested via simulation and experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.