• Title, Summary, Keyword: Single-phase

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Characteristic Analysis of Single Phase Line-start Permanent Magnet Synchronous Motor Considering Circuit Parameters (단상 직립 기동형 영구자석 동기기의 회로정수에 따른 특성 해석)

  • 강규홍;홍정표
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.6
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    • pp.262-270
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    • 2003
  • In this paper, the characteristics of single-phase line-start permanent magnet synchronous motor driven by constant voltage are analyzed on d-q axis vector diagram and compared with that of current controlled motor. The coupled method of symmetrical coordinates and d-q axis voltage equation are applied to the analysis method like the analysis of single-phase induction motor. From the result of the analysis, it is seen that motors driven by constant voltage source have effects on not only the amplitude of current and torque but also current and current phase angle, so overall characteristics such as power factor and load angle are affected by circuit parameters. For precise analysis and design of single-phase line-start synchronous motor, its characteristics should be analyzed on d-q axis vector plan in consideration of the variation of circuit parameters.

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

  • Park, Jae-Hwae;Jin, Tae-Seok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.2
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    • pp.170-175
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    • 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.

A Low COST SOFT-SWITCHED AC-TO-TC CONVERTER

  • 최주엽;목형수;김택용
    • Proceedings of the KIPE Conference
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    • pp.135-140
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    • 1997
  • A highly efficient single-phase/three-phase compatible ac-to-dc converter is proposed and analyzed, which includes three identical single-phase both soft-switched dc-to-dc converter with boost converter as a pre-regulator for input power factor correction (PFC). The proposed converter structure provides a cost reduction and easy implementation of compatibility between single-phase 220V and three-phase 220V/380V with their inputs in delta or wye connections.

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Air-Water Two-Phase Flow Performances of Centrifugal Pump with Movable Bladed Impeller and Effects of Installing Diffuser Vanes

  • Sato, Shinji;Furukawa, Akinori
    • International Journal of Fluid Machinery and Systems
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    • v.3 no.3
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    • pp.245-252
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    • 2010
  • It's known that pump head of centrifugal impeller with lager blade outlet angle is kept higher in air-water two phase flow condition, though the efficiency in water single phase flow condition is inferior. In the present study, a centrifugal impeller with variable blade outlet angles, that has higher efficiencies in both water single phase flow and air-water two phase flow conditions, is proposed. And the performances of the centrifugal impeller with variable blade outlet angles were experimentally investigated in both flow conditions of single and two-phase. In addition, effects of installing diffuser vanes on the performances of centrifugal pump with movable bladed impeller were also examined. The results are as follows: (1) The movable bladed impeller that proposed in this study is effective for higher efficiency in both water single phase and air-water two phase flow conditions. (2) When diffuser vanes are installed, the efficiency of movable bladed impeller decreases particularly at large water flow rate in water single-phase flow condition; (3) The performances of movable bladed impeller are improved by installing of diffuser vanes in air-water two-phase flow condition at relatively small water rate. The improvement by installing of diffuser vanes however disappears at large water flow rate.

The conceptual design and analysts of three phase superconducting fault current limiter (일체형 삼상 고온 초전도 한류기의 단락 특성 해석)

  • Lee, Sueng-Je;Lee, Chan-Joo;Lee, Chang-Yul;Jang, My-Hye;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • pp.94-97
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    • 1998
  • The conceptual design of integrated three phase superconducting fault current limiter (SFCL) is presented. And through simulation of power system where this SFCL is installed, the characteristics of this SFCL is analyzed. It is like three-phase transformer. So it has the same characteristics with inductive single phase SFCL. But it has more merits than single phase SFCL. Differently to single phase SFCL, integrated three phase SFCL induces impedance at all phase by any single phase fault to protect the power system more safely.

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Scott Transformer Modeling using Simulink on the AC Substation (Simulink를 이용한 교류 급전변전소의 스코트변압기 모델링)

  • Kim, Tae-Geun;Park, Young;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • pp.2317-2322
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    • 2011
  • In three-phase power, when the power is supplied to the single phase load, there is the unbalance of load in the three-phase power. So the scott transformer is used in the power system to supply a single phase load in three-phase power without the unbalance of loads. Especially, the scott transformer is used in the AC substation of electric railroad. Two single phase transformers are combined by T-wiring in the scott transformer. So, two single phase voltage is provided by differing $90^{\circ}$ phase in three-phase power. The selection of related equipment and correction of protective relay are not easy from characteristic of the scott transformer when shunt and ground faults occur. In this paper, electric model of the scott transformer is suggested and the current of the scott transformer in shunt and ground faults is analyzed. Also, the scott transformer model is demonstrated by using Sinulink.

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Digital PLL Control for Phase-Synchronization of Grid-Connected PV System (계통 연계형 태양광 발전 시스템의 위상 동기화를 위한 디지털 PLL 제어)

  • 김용균;최종우;김흥근
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.9
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    • pp.562-568
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    • 2004
  • The frequency and phase angle of the utility voltage are important in many industrial systems. In the three-phase system, they can be easily known by using the utility voltage vector. However, in the case of single phase system, there are some difficulties in detecting the information of utility voltage. In conventional system, the zero-crossing detection method is widely used, but could not obtain the information of utility voltage instantaneously. In this paper, the new digital PLL control using virtual two phase detector is proposed with a detailed analysis of single-phase digital PLL control for utility connected systems. The experimental results under various utility conditions are presented and demonstrate an excellent phase tracking capability in the single-phase grid-connected operation.

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

  • Kim, Hyun-Geun;Jin, Seong-Min;Lee, Sang-Hee;Lee, Su-Hyoung;Kim, Joohn-Sheok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.6
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    • pp.496-503
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    • 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.

Comparative Analysis of Voltage Unbalance Factor on the use of Linear and Non-linear loads in Three-phase Four-wire Low Voltage Distribution Line (3상 4선식 저압 배전선로에서 선형 및 비선형 부하의 사용시 전압 불평형률 비교 분석)

  • Kim, Jong-Gyeum;Kim, Ji-Myeong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.3
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    • pp.587-592
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    • 2017
  • In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

Correlation between Trunk Stabilization Muscle Activation and Gait Parameters (몸통 안정화 근육과 보행요소의 상관관계)

  • Chae, Jung-Byung;Jung, Ju-Hyeon
    • PNF and Movement
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    • v.17 no.1
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    • pp.111-118
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    • 2019
  • Purpose: This study aimed to investigate the correlation between trunk stabilization muscle activation and the parameters of gait analysis in healthy individuals. Methods: Thirty healthy adults (15 male, 15 female) with no history of lower back pain (LBP) or current musculoskeletal and neurological injuries were studied. Trunk stabilization muscle activation (e.g., external oblique, internal oblique, transverse abdominis, erector spinae) were assessed using surface electromyography. To analyze gait, we measured temporal parameters (e.g., gait velocity, single support phase, double support phase, swing phase, and stance phase) and a spatial parameter (e.g., H-H base of support). Results: A statistically significant correlation was found between the internal oblique, transverse abdominis, and erector spinae muscle activity and gait velocity, single support phase, double support phase, swing phase, and stance phase. No statistically significant correlation was found between the external oblique muscle activity and the gait velocity, single support phase, double support phase, swing phase, and stance phase. No statistically significant correlation was found between the external oblique, internal oblique, transverse abdominis, and erector spinae muscle activity and the spatial parameter. Conclusion: This study demonstrated that a relationship exists between trunk stabilization muscle activation and temporal parameter (i.e., gait velocity, single support phase, double support phase, swing phase, and stance phase) during gait analysis. Therefore, the trunk's stabilizer muscles play an important role in the gait of healthy individuals.