• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3425-3430
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• 2013

The fast-growing market in wireless communications has led to the development of multi-standard mobile terminals. In this paper, a frequency-tunable active RC bandpass filter for multi-standards wireless communication system is designed using an active inductor. The conventional bandpass filter design methods employ the high order filter or high quality factor Q to improve the stopband attenuation characteristics and frequency selectivity of the passband. The proposed bandpass filter based on the high Q active inductor has an improved frequency characteristics. The center frequency and gain of the designed bandpass filter is tuned by employing the tuning circuit. We have performed the simulation using TSMC $0.18{\mu}m$ process parameter to analyze the characteristics of the designed active RC bandpass filter. The bandpass filter with Q=20.5 has 90MHz half power bandwidth at the center frequency of 1.86GHz. Moreover, the center frequency of the proposed bandpass filter can be tuned between 1.86~2.38GHz for the multi-standards wireless communication system using the capacitor of the tuning circuit.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.155-156
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• 2014

본 논문은 계통연계 목적으로 사용하는 LCL필터의 공진현상을 억제하기 위한 간단한 능동 댐핑 원리와 방법을 보인다. LCL필터는 기존의 1차 필터인 L필터에 비해 적은 동량으로 효과적인 출력파형의 고조파 저감 효과를 갖지만, LC파트 추가로 인해 허수축에 공진복소극이 존재하여 필연적으로 시스템에 공진이 발생하게 된다. 본 논문에서는 추가적인 센서나 수동소자의 사용 없이 LCL필터의 공진복소극을 상쇄하는 노치필터를 제어기에 적용하여 시스템의 안정성을 확보한다. 시뮬레이션을 수행하여 타당성을 입증한다.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.53-59
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• 1999

In this paper, a bi-directional UPS with the performance of active power filter has been proposed. The operation of the proposed system can be divided into two modes, such as the active power filter mode and the battery back-up power mode. To improve the transient response for the effective compensation of harmonics and reactive power in active power filter mode, a novel closed-loop control strategy is used to calculate the reference current instantaneously. Finally, the performance of proposed UPS is verified by the simulation and experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5B
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• pp.639-644
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• 2001

본 논문에서는 저전압(2V) 동작이 가능하도록 high-swing cascode 방식을 이용한 능동소자를 제안하고, 이를 이용하여 400MHz의 차단주파수 특성을 나타내는 저역통과 능동필터를 설계하였다. 제안된 적분기는 이득특성에 영향을 주는 트랜스컨덕스값을 증가시키기 위해 CMOS 상보형 캐스코드 방식을 이용하여 구성되었다. 0.25$\mu\textrm{m}$ CMOS n-well 공정 파라미터를 이용한 Hspice 시뮬레이션 결과, 제안된 적분기는 2V 공급전압하에서 42dB의 이득값과 200MHz의 단위이득주파수 특성을 나타내었다. 또한 이를 이용하여 설계된 저역통과 능동필터는 400MHz의 차단주파수 특성을 나타내고 368MHz에서 416MHz까지 튜닝이 가능하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.4
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• pp.403-408
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• 2000

In this paper, voltage control APF(Active Power Filter) is introduced to improve power factor and reduce harmonics generated from nonlinear load. The voltage controlled APF which is consisted of inverter and passive filter operates with nonlinear load simultaneously. Real power supplies from main power to load and reactive power provides from APF to load. According to the results o experiment and simulation, it is proved that the proposed system has the performance of improving power factor and reducing harmonics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.1068-1076
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• 1996

In this paper, a new continuous-time current-mode integrator as basic building block of the low-voltage analyog current-mode active filters is proposed. Compared to the current-mode integrator which is proposed by Zele, the proposed current-mode integrator had higher unity gain frequency and output impedance in addition to lower power dissipation. And also, a current-mode third-order lowpass active filter is designed with the proposed current-mode integrator. The designed circuits are fabricated using the ORBIT's $1.2{\mu}{\textrm{m}}$ deouble-poly double-metal CMOS n-well process. The experimental results show that the filter has -3dB cutoff frequency at 44.5MHz and 3mW power dissipation with single 3.3V power supply and also $0.12mm^{2}$ chip area.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.149-151
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• 2006

본 논문에서는 고조파 보상과 역율 보상을 실시하고, 전원 전압 불평형시 보상을 실시하는 직 병렬 능등전력필터에 관하여 연구하였다. 직렬형 능동전력필터에서는 고조파에 대한 보상 전압만을 발생하여 제어하고, 병렬형 능동전력필터에서는 역율에 대한 보상하는 전류만을 발생하여 제어한다. 또한, 불평형 전원 전압에 대한 보상은 직렬형 능동전력필터에서 실시하며, 고조파 보상과 역율 보상은 성능함수에 의해 계산되어지며, 불평형 전원 전압 보상은 대칭 좌표법을 이용하여 계산되어진다. 제시된 실험 결과들은 알고리즘의 타당성과 유효성을 검증한다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.363-364
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• 2015

최근 에너지 저장장치의 사용과 신재생에너지를 이용한 분산발전의 규모가 점차 확대됨에 따라 계통에 원활한 전류주입과 주입 전류의 스위칭 고조파 리플성분 저감을 위해 LCL 필터를 이용한 계통연계형 인버터가 널리 사용되고 있다. 이러한 계통연계형 인버터의 주입전류 특성은 LCL 필터에 종속적이기 때문에 정밀한 주입전류제어를 위해 LCL 필터의 정확한 해석이 요구된다. 본 논문에서는 명확한 LCL 필터 해석을 위해 LCL 필터의 인덕터 직렬 내부저항을 고려한 LCL 필터 특성을 해석하였으며, 이러한 해석을 기반으로 LCL필터 공진현상에 따른 주입전류의 THD를 저감하기 위한 인덕터 가상 직렬저항 능동댐핑 기법을 제안하고 HILS 실험을 통해 제안하는 능동댐핑 기법의 성능을 검증하였다.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.3-7
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• 2001

In active sonar system using CW signal, when the noise included reverberation has not the white characteristics, the CFAR detector estimates high threshold. Because of this reason it cannot detect targets and not resolve the closely spaced multiple targets. In order to solve these problems, we propose an adaptive reverberation rejection filter The proposed filter is composed of an adaptive filter and a fixed filter with its coefficients. To study the performance of the proposed adaptive reverberation rejection filter, various experiments have been performed under In moving active sonar environments. As a results, the proposed method has the improved performance than the previous methods.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1515-1520
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• 2004

In this paper, a new continuous-time bandpass active filter for lour-voltage applications is proposed. The active filter is composed of the CMOS complementary cascode circuit which can increase trans-conductance of an active element. These results are verified through the 0.25$\mu\textrm{m}$ CMOS n-well parameter hspice simulation. As a result, the gain and the unity gain frequency is 42dB and 200MHz respectively in the integrator. Additionally, center frequency of the bandpass active filter is 747kHz. And also bandwidth of the filter is 649kHz on 2V supply voltage.