• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.219-222
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• 2001

In this paper, we firstly proposed to the boost type PFC circuit for a power factor improving and a harmonic decreasing. The predict current control method is used to control these PFC circuit. This current control method has a merit that is possible to improve power factor and harmonics. In addition, we suggested to the active DC filter, which is connected with the DC output terminal, in order to compensate the DC ripple components. Consequently, these results are proved by the simulation tool, PSIM, which is an exclusive simulator of power electronics.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.232-233
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• 2016

본 논문은 계통과 연계된 3상 전압원 인버터를 기반으로 한 BESS의 능동 단독 운전 검출 방법을 제안한다. 제안하는 기법은 PR제어기와 필터를 가지고 기본파 전류와 2차 고조파 전류를 이용해 수행하였다. 단독운전은 BESS로부터 정격전류의 1% 2차 고조파를 주입하기 때문에 PCC점에서의 2차 고조파 전압 변화량을 검출 할 수 있다. 제안하는 기법은 모든 조건하에 정확하고 빠르게 검출 할 수 있다. IEEE와 UL1741에서 제시하는 단독 운전 기준 시험 회로를 구성하여 PSCAD/EMTDC 소프트웨어를 통한 시뮬레이션과 5kW 하드웨어 장치를 통해 제안된 단독 운전 검출 방법을 검증하였다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.467-468
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• 2015

능동형필터는 주로 비선형 부하로 부터 발생되는 정수배의 고조파를 보상하는데 응용되어 왔다. 본 논문에서는 국가핵융합연구소(NFRI)의 KSTAR 주장치의 전원공급장치인 PF MPS가 가동되면서 특이한 저차수 대역의 비정수 고조파가 발생되는데 이는 MG(motor generator)와 RPC (Reactive Power Compensator)간의 병렬공진 확대현상으로 나타나 고조파 전류의 증가, 전압왜형 상승 등 안정적인 전력계통 운영에 영향을 주고 있다. 따라서 이의 원인이 되는 특이성의 비정수 고조파를 저감시키기 위한 제어 알고리즘 개발과 모의시험에 관한 연구내용을 다루고자한다. 지금까지 개발된 알고리즘은 주로 정수배 고조파만을 대상으로 한 FFT의 일괄보상, 혹은 개별차수 보상방식이었으나 여기서는 DQ 변환 알고리즘을 채용하여 정수배 고조파는 물론 0.5차 단위의 비정수 고조파까지 제어하는 기술을 다루었다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.7
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• pp.500-508
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• 2000

Basic design for single-phase active power filter, which aims at railway application provided with PWM-controlled converters, is comprehensively studied and its performance is presented in this paper. Active power filters are used to compensate railway signaling and public telecommunication interference due to the high-order harmonic currents generated in railway traction locomotives. A type of hybrid digital filter which is composed of low pass filter and high pass filter is proposed so that the desired harmonic reference current with accurate magnitude and phase shift can be extracted from catenary line current. A design criteria to determine input inductor L and output capacitor C is also described, considering voltage, current, PWM pattern, and switching frequency of the main converters. Finally, computer simulation and DSP-based experiments resulted from laboratory test are presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.651-659
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• 2010

In this paper, a new six-port direct conversion receiver for high-speed multi-band multi-mode wireless communication system such as software defined radio(SDR) is proposed. The designed receiver is composed of two CMOS four-port BPSK receivers and a dual-band one-stage polyphase filter for quadrature LO signal generation. The four-port BPSK receiver, implemented in 0.18 ${\mu}m$ CMOS technology for the first time in microwave-band, is composed of two active combiners, an active balun, two power detector, and an analog decoder. The proposed polyphase filter adopt type-I architecture, one-stage for reduction of the local oscillator power loss, and LC resonance structure instead of using capacitor for dual-band operation. In order to extent the operation RF bandwidth of the proposed six-port receiver, we include I/Q phase and amplitude calibration scheme in the six-port junction and the power detector. The calibration range of the phase and amplitude mismatch in the proposed calibration scheme is 8 degree and 14 dB, respectively. The validity of the designed six-port receiver is successfully demonstrated by modulating M-QAM, and M-PSK signal with 40 Msps in the two-band of 900 MHz and 2.4 GHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.840-845
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• 2013

In this paper, the broadband frequency double down-converter based on LC filter technologies has been designed and implemented, and its performances are introduced. The Designed frequency double down-converter is consisted with a low-noise amplifier, mixer, IF amplifier, LC filter, DC-block capacitor and RF-bypass capacitor. Especially, instead of active devices of a typical converter, the suggested converter designed using passive devices to provide both low-power consumption and low-cost model. As results of the measurement, the implemented frequency double down-converter realizes the broadband performance with the bandwidth of 100MHz (13~113MHz) at the center frequency of 63MHz, and its gain is approximately 40dB.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.5
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• pp.249-257
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• 2002

In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for the combined system of series active and shunt passive power filter is proposed, where no low/high-pass filters are used in deriving the reference voltage for compensation. The phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. In order to remove the phase delay in generating the reference voltage for compensation, the reference of 5th and 7th harmonic components is predicted one-sampling ahead. The validity of the proposed scheme has been verified for 3[kVA] proto-type active power filter system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.7
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• pp.296-303
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• 1986

The active filter of current injection type is the device which eliminates the harmonics in ac line by injecting the harmonic compensating current into the ac side. And its harmonic reduction performance is entirely dependent on the control scheme of the current-fed inverter and the harmonic compensating current becomes the PWM wave by the inverter. This PWM compensating current can be determined by selecting the switching function properly which eliminates the harmonics up to any order with using no independent sources. The new injection current model is derived by the proposed method which is called the optimized injection method. The overall characteristics of the proposed method are investigated through digital computation and the feasibility is proved with experimental results obtained from the Z-80 microcomputer control of the active filter.

• Journal of Sensor Science and Technology
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• v.3 no.1
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• pp.54-60
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• 1994

In this paper, the multi-sensor signal processing IC is designed. It consists of an analog multiplexer for selection of multi-sensor signals, active filters for noise rejection and signal amplification, and a sample and hold circuit for interface with digital signal processing. By implementing these circuits with CMOS transistors, integration, low power dissipation and miniaturization of the total signal processing system have been made possible.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1077-1080
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• 1992

In this paper suggested methods for current control in active filter are using the triangular carriers which were composed of independently generated threefold carriers and controllable current source which compensates the harmonics generated independently from the types of the load with instantaneous amplitude adjusting from the maximum magnitude of the compensating currents. And the 2-nd order high pass passive filter connected to the source finally supplies pure sinusoidal waves by suppressing the residual harmonics which cannot removed by the active filter. As the typical load which generates the harmonics, a rectifier was set and the system was also designed by simulations and implementations.