• 제목/요약/키워드: current phase

검색결과 5,373건 처리시간 0.037초

상전류 센서없는 3상 PWM 정류기의 전류제어 (Current Control of Three-Phase PWM Rectifiers without Phase Current Sensors)

  • 임대식;김해준;이동춘
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 1999년도 전력전자학술대회 논문집
    • /
    • pp.307-310
    • /
    • 1999
  • This paper proposes a novel current control method of three-phase PWM rectifiers without phase current sensors. The features of this method are to reconstruct phase currents by using switching pattern of space vector modulation and to estimate phase currents by a predictive state observer for practical applications. Simulation results show that the performance of the proposed system is nearly the same as that of sensor-based system.

  • PDF

3상계통에서 단상변압기에 대한 단락전류계산 기법 (A Technique for a Short-Circuit Current Calculation to The Single-Phase Transformer in the Three-Phase Systems)

  • 박재훼;진태석
    • 전기학회논문지P
    • /
    • 제57권2호
    • /
    • pp.170-175
    • /
    • 2008
  • This paper describes the exact short-circuit current calculation technique for the single-phase transformer which is installed in the three-phase systems and shorted in the secondary side. Not only the results for a short-circuit current calculation in the existing literatures are wrong, but also little literature deals with the short-circuit current for a single-phase transformer. So, this paper presents a theoretical study and calculation method for a single-phase short current. The validity of the presented method is investigated through Simulation using "Power Tools" and "PSim" program.

분리된 삼상 자속구속형 전류제한기와 일체화된 삼상 자속구속형 전류제한기의 전류제한 특성 비교 (Comparison of Fault Current Limiting Characteristics between the separated Three-phase Flux-lock Type SFCL and the Integrated Three-phase Flux-lock Type SFCL)

  • 두승규;두호익;김민주;박충렬;김용진;이동혁;한병성
    • 한국전기전자재료학회논문지
    • /
    • 제22권8호
    • /
    • pp.689-693
    • /
    • 2009
  • We investigate the comparison of fault current characteristics between the separates three-phase flux-lock type superconducting fault current limiter(SFCL) and integrated three-phase flux-lock type superconducting fault current limiter(SFCL). The single-phase flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil on an iron core and superconducting elements are connected to secondary coil in series. Superconducting elements are used by the YBCO coated conductor. The separated three-phase flux-lock type SFCL consists of single-phase flux-phase type SFCL in each phase. But the integrated three-phase flux-lock type SFCL consists of three-phase flux-reactors wound on an iron core. Flux-reactor consists of the same turn's ratio between coil 1 and coil 2 for each single phase. To compare the current limiting characteristics of the separated three-phase flux-lock type SFCL and integrated three-phase flux-lock type SFCL, the short circuit experiments are carried out fault condition such as the single line-to-ground fault. The experimental result shows that fault current limiting characteristic of the separated three-phase flux-lock type SFCL was better than integrated three-phase flux-lock type SFCL. And the integrated three-phase flux-lock type SFCL has an effect on sound phase.

단일 전류 센서를 이용한 2상 하프브릿지 인버터의 상전류 측정 방법 (A Novel Current Measurement Method for Two-Phase Half-bridge Inverter using Single Current Sensor)

  • 조영훈;목형수;장도현;김상훈
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2007년도 하계학술대회 논문집
    • /
    • pp.193-195
    • /
    • 2007
  • This paper proposed a novel current measurement method for two-phase half-bridge inverter using single current sensor. The proposed method measures DC link input current and a phase current simultaneously and reconstructs each phase currents by simple calculation according to voltage vector. The commutation modes of two-phase half-bridge inverter is analized. The current sampling and reconstructing method is also presented. The proposed method is verified through simulation and experimental results on two-phase induction motor drive system.

  • PDF

대칭분 전압 단위 벡터를 이용한 송전선로 보호용 고장상 선택 알고리즘 (Fault Phase Selection Algorithm using Unit Vector of Sequence Voltages for Transmission Line Protection)

  • 이명수;이재규;김수남;유석구
    • 대한전기학회논문지:전력기술부문A
    • /
    • 제51권9호
    • /
    • pp.460-466
    • /
    • 2002
  • A reliable fault phase selection algorithm plays a very important role in transmission line protection, Particularly in Extra High Voltage (EHV) networks. The conventional fault phase selection algorithm used the phase difference between positive and negative sequence current excluding load current. But, it is difficult to pick out only fault current since we can not know when a fault occurs and select the fault phase in weak-infeed conditions that dominate zero-sequence current in phase current. The proposed algorithm can select the accurately fault phase using the sum of unit vectors which are calculated by positive-sequence voltage and negative-sequence voltage.

단상 부스트 PFC 컨버터용 가상 DQ 동기좌표계 기반 고성능 전류제어 알고리즘 (High Performance Current Control Algorithm Based on Virtual DQ Synchronous Reference Frame for Single-Phase Boost PFC Converter)

  • 김현근;진성민;이상희;이수형;김준석
    • 전력전자학회논문지
    • /
    • 제22권6호
    • /
    • pp.496-503
    • /
    • 2017
  • This study proposes a high-performance current control algorithm for a diode-bridge-type single-phase boost power factor correction (PFC) converter. The conventional asynchronous single-phase current controllers that directly control AC-type current tend to be accompanied by steady-state errors due to their poor dynamic characteristics for the transient-state, which can be attributed to bandwidth limitations and phase delays. In the proposed algorithm, an ideal current control with minimal phase delays and steady-state errors can be achieved by using a virtual DQ synchronous reference frame and by controlling the synchronous reference frame excluding the frequency component in the single-phase system. The performance of the conventional asynchronous single-phase current controller is compared with that of the proposed algorithm through simulation and experiments, and the results have confirmed the superiority of the latter.

커뮤테이션 구간의 토크리플 저감을 위한 SRM의 토크 분배 함수 기법 (Torque Sharing Function of SRM for Torque Ripple Reduction in Commutation Region)

  • 김태형;;이동희;안진우
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2007년도 추계학술대회 논문집
    • /
    • pp.148-150
    • /
    • 2007
  • A novel torque sharing function (TSF) is presented. To improve efficiency and to reduce torque ripple in commutation region, only a phase torque under commutation is regulated to produce a uniform torque. And the torque developed by the other phase remains with the previous state under a current limit of the motor and drive. If the minimum change of a phase torque reference can not satisfy the total reference torque, two-phase changing mode is used. Since a phase torque is constant and the other phase torque is changed at each rotor position, total torque error can be reduced within a phase torque error limit. And the total torque error is dependent on the change of phase torque. To consider non-linear torque characteristics and to suppress a tail current at the end of commutation region, the incoming phase current is changed to torque increasing direction, but the outgoing phase current is changed to torque decreasing direction. So, the torque sharing of the outgoing phase and incoming phase can be smoothly changed with a minimum current cross over. The proposed control scheme is verified by some computer simulations and experimental results.

  • PDF

토크분배함수를 이용한 SRM의 적접토크제어기법 (Direct Torque Control Scheme of Switched Reluctance Motor using Novel Torque Sharing Function)

  • 안진우;이동희;김태형
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
    • /
    • pp.138-140
    • /
    • 2007
  • A novel non-linear logical torque sharing function (TSF) is presented. To improve efficiency and to reduce torque ripple in commutation region, only a phase torque under commutation is regulated to produce a uniform torque. And the torque developed by the other phase remains with the previous state under a current limit of the motor and drive. If the minimum change of a phase torque reference can not satisfy the total reference torque, two-phase changing mode is used. Since a phase torque is constant and the other phase torque is changed at each rotor position, total torque error can be reduced within a phase torque error limit. And the total torque error is dependent on the change of phase torque. To consider non-linear torque characteristics and to suppress a tail current at the end of commutation region, the incoming phase current is changed to torque increasing direction, but the outgoing phase current is changed to torque decreasing direction. So, the torque sharing of the outgoing phase and incoming phase can be smoothly changed with a minimum current cross over. The proposed control scheme is verified by some computer simulations and experimental results.

  • PDF

EPLD 로직구현을 통한 델타변조기법에 의한 스위치드 리럭턴스 전동기의 전류제어 (Current Control of Switched Reluctance Motor with Delta Modulation Method on EPLD Logic Design)

  • 윤용호;김재문
    • 전기학회논문지P
    • /
    • 제57권4호
    • /
    • pp.356-361
    • /
    • 2008
  • The conventional drive system of SRM has a current sensor per each phase. The torque demand signal generated by the outer control loop is translated into individual current reference signal for each phase. The torque is controlled by regulating these currents. Using the SRM in a variable-speed control, the phase currents are generally regulated to achieve a square wave. The simplest form of current regulation uses fixed frequency delta modulation of the phase voltages. The aim of this paper is to regulate 3-phases current of SRM by only single current sensor using delta modulation with digital chip. In this paper, the asymmetric bridge converter which is able to control independently phases and be excited simultaneously is used as the driver system for 6/4 poles SRM. And the current sensor is replaced 3 sensors of each phase with only one on bus line of converter so as to detect current of every phase. The proposed delta modulation technique has been implemented in a simple digital logic circuit using EPLD(Electrically Programmable Logic Device). This method is verified through simulation and experiment results.

단상 인버터를 사용한 중성선 전류 저감 기법 (Neutral Current Reduction Method Using Single-Phase Inverter)

  • 민준기;김효성;최재호
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
    • /
    • pp.155-157
    • /
    • 2005
  • This paper analyzed the adoption possibility of a low cost single phase active power filter as the neutral current reduction device in three-phase four-wire power system with the balanced or/and unbalnaced nonlinear load conditions. Proposed system can make neutral line current to within rated vale without the phase current THD change of the installed phase line.

  • PDF