• 제목/요약/키워드: Active method

검색결과 6,289건 처리시간 0.036초

태양광 MIC 시스템의 효율향상을 위한 새로운 Active Clamp 스위칭 기법 (A Novel Active Clamp Switching Method To Improve of Efficiency For Photovoltaic MIC)

  • 박병철;박지호;송성근;박성준;신중린
    • 전력전자학회논문지
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    • 제18권5호
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    • pp.477-484
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    • 2013
  • This paper proposes a novel switching method of active clamp snubber for efficiency improvement of PV module integrated converter(MIC) system. Recently, MIC solar system is researched about the efficiency and safety. PV MIC system is used active clamp method of snubber circuit for the price and reliability of the system. But active clamp snubber circuit has the disadvantage that system efficiency is decreased for switch operating time because of heat loss of resonant between snubber capacitor and leakage inductance. To solve this problem, this paper proposes a novel switching method of the active clamp. The proposed method is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time and through simulations and experiments proved the validity.

A Novel Active User Identification Method for Space based Constellation Network

  • Kenan, Zhang;Xingqian, Li;Kai, Ding;Li, Li
    • International Journal of Computer Science & Network Security
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    • 제22권12호
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    • pp.212-216
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    • 2022
  • Space based constellation network is a kind of ad hoc network in which users are self-organized without center node. In space based constellation network, users are allowed to enter or leave the network at any given time. Thus, the number of active users is an unknown and time-varying parameter, and the performance of the network depends on how accurately this parameter is estimated. The so-called problem of active user identification, which consists of determining the number and identities of users transmitting in space based constellation network is discussed and a novel active user identification method is proposed in this paper. Active user identification code generated by transmitter address code and receiver address code is used to spread spectrum. Subspace-based method is used to process received signal and judgment model is established to identify active users according to the processing results. The proposed method is simulated under AWGN channel, Rician channel and Rayleigh channel respectively. Numerical results indicate that the proposed method obtains at least 1.16dB Eb/N0 gains compared with reference methods when miss alarm rate reaches 10-3.

A phase calibration method of active phased array antennas for satellite communication

  • Noh, Haeng-Sook;Jeon, Soon-Ik;Chae, Jong-seock
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 ITC-CSCC -1
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    • pp.519-522
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    • 2002
  • An active phased array antenna consists of many channels. Each channel has a different initial phase shift and gain because of the inequality in the active circuits themselves, interface between radiators and active circuits, and beam-forming circuits and other antenna system configurations. This raises an inherent problem in active phased array antennas. To compensate for this problem the initial phase and gain of each channel should be calibrated. This paper presents an efficient calibration method for an initial phase variation of each channel in active phased array antennas. We tested our method in an active phased array antenna, and obtained good results in the radiation pattern and beam direction of antenna.

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An Over Current Protection Scheme for Hybrid Active Power filter

  • Lee Woo-Cheol;Chae Beom-Seok;Hyun Dong-Seok;Lee Taeck-Kie
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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    • pp.571-575
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    • 2001
  • A protection scheme for hybrid active power filters, which is combined shunt passive filter and small rated series active filter, is presented and analyzed in this paper. The proposed series active power filter operated as a high impedance 'k($\Omega$)' to the fundamental component when over current occurs in the power distribution system, and three control strategies are proposed in this paper. The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame (SRF) and the third is the method by detecting the input voltage. When the over current occurs in the power distribution system, the proposed scheme protects the series active power filter without additional protection circuits. The validity of proposed protection scheme is investigated through experimental result for the prototype hybrid active power filter system.

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영구자석 동기모터 진동 및 과전류 저감을 위한 능동단락회로 제어 기법 (Active Short Circuit Control Method to Reduce Overcurrent and Oscillation Current in PMSM)

  • 최종원;김윤재
    • 전력전자학회논문지
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    • 제27권4호
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    • pp.339-347
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    • 2022
  • This study proposes the mitigation method for overcurrent and oscillation motor current in an active short-circuit operation. This operation is attracting attention as the safe state of electric vehicle traction inverters. However, the active short-circuit operation generates oscillation and overcurrent of motor currents during a transient state. The proposed method uses two different safe states in PMSM, such as active short circuit and freewheeling. The active short circuit is used for safe state in a steady state. To reduce the overshoot and oscillation, a freewheeling state is injected between active short-circuit operation by comparing the motor phase current with an analytically calculated steady-state motor current. Freewheeling state is only used in a transient state. The performance is demonstrated through simulations and experimental results. The peak current of the motor was reduced from 52 A to 40 A, and oscillation time was reduced.

입체음향 제작기법을 통한 능동소음제어 방법의 효율성 (Effectiveness of Active Noise Control through Three-Dimensional Sound)

  • 박준홍;김준종;민동기
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.955-956
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    • 2014
  • Active noise control is noise reduction method by generate anti-phase control signal for destructive interference of through control speaker. purpose of this paper is create a virtual control source at a using the DBAP(Distance Based Amplitude Panning) algorithm which is one of the three-dimensional sound reproduction method, and verified through the experimentally for noise control method through the virtual control source. We compared active noise method by using one control speaker with active noise control method by using DBAP algorithm.

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Beam-rotating machinery system active vibration control using a fuzzy input estimation method and LQG control technique combination

  • Lee, Ming-Hui
    • Smart Structures and Systems
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    • 제10권1호
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    • pp.15-31
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    • 2012
  • This study proposes an active control method to suppress beam-rotating machinery system vibrations. The present control method is a combination of the fuzzy input estimation method (FIEM) and linear quadratic Gaussian problem (LQG) algorithms. The FIEM can estimate the unknown input and optimal states by measuring the dynamic displacement, the optimal estimated states into the feedback control; thereby obtaining the optimal control force for a random linear system. Active vibration control of a beam-rotating machinery system is performed to verify the feasibility and effectiveness of the proposed algorithm. The simulation results demonstrate that the proposed method can suppress vibrations in a beam-machine system more efficiently than the conventional LQG method.

직렬 능동 보상기의 과전류 보호방법에 관한 연구 (A Study on the Over-Current Protection Method of A Series Active Compensator)

  • 채범석;이우철;이택기;현동석
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제51권6호
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    • pp.321-329
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    • 2002
  • A protection scheme for series active compensator is presented and analyzed in this paper. The proposed series active compensator operated as a high impedance K($\Omega$) to the fundamentals when short-circuit faults occur in the power distribution system, and two control strategies are proposed in this paper The first is the method by detecting the fundamental source current through the p-q theory, the second is the method by detecting the fundamental component of load current in Synchronous Reference Frame(SRF). When the short-circuit faults occur in the power distribution system, the proposed scheme can protect the series active compensator without additional protection circuits. The validity of the Proposed Protection scheme was investigated through experimental results.

고속 회전체의 능동 밸런싱에 관한 연구 (II): 제어 안정성과 응용 (A Study on the Active Balancing for High-Speed Rotors (II): Control Stability and Application)

  • 김종수;문종덕;이수훈
    • 한국정밀공학회지
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    • 제19권4호
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    • pp.147-153
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    • 2002
  • In the preceding research, the active balancing device, which is an electro-magnetic type, has been developed and active balancing method using influence coefficient method is also proposed. The stability of active balancing control is studied in this paper. A stable condition for active balancing control is derived by estimating errors of influence coefficients. A gain scheduling control using influence coefficients of the reference model is proposed when dynamic characteristic of rotor system is changed. The stability of the balancing method is verified by experiments.

실시간 하이브리드 실험법을 이용한 대형 MR감쇠기의 준능동 제어알고리즘 성능 비교 (Performance Comparison of Semi-active Control Algorithms for a Large-scale MR Damper using Real-time Hybrid Test Method)

  • 박은천;이성경;이헌재;최강민;문석준;정형조;정희산;민경원
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 추계학술대회논문집
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    • pp.648-654
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    • 2007
  • This paper presents the result of a comparison study to evaluate the performance of several semi-active control algorithms for use with large-scale MR damper applied to a building structure under seismic excitation using real-time hybrid test method. Recently, a variety of semi-active control algorithm studies are developed and generally evaluated the performance by using numerical analysis. In this paper real-time hybrid test method was applied to performance evaluating of semi-active control algorithms including a clipped optimal algorithm and the modulated homogeneous friction algorithm.

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