• Title, Summary, Keyword: Single-phase system

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Operational Characteristic Analysis of a Single-Phase PCS for PV Power Generation System with Active Filter Function (엑티브 필터 기능을 가지는 단상 태양광 PCS의 운전특성 해석)

  • Jang, Seong-Jae;Seo, Hyo-Ryong;Kim, Gyeong-Hun;Park, Sang-Soo;Kim, Sang-Yong;Park, Min-Won;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • pp.1051_1052
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    • 2009
  • This paper deals with operational characteristic analysis of a single-phase PCS (Power Conditioning System) for PV (Photovoltaic) power generation system with AF (Active Filter) function. The theory of dq transformation has been applied to the control strategy of a single-phase PV power generation system to implement the AF function. Application of the virtual two-phase using phase-shift makes it possible to use the dq theory for the single-phase PV power generation system. The authors are sure that the proposed system is a very useful to compensate harmonics caused by nonlinear loads in a single-phase utility system. In this paper, not only a theoretical aspect of the single-phase PV-AF system is discussed, but also the DSP (Digital Signal Processor) based experiment results are presented to demonstrate the effectiveness of the single-phase PV-AF system.

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A Switched Reluctance Motor for Single Phase Drive (단상구동 Switched Reluctance Motor의 해석)

  • Lim, Jun-Young;Kim, Hyung-Sup;Oh, Jae-Yoon
    • Proceedings of the KIEE Conference
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    • pp.1951-1953
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    • 1997
  • A switched reluctance motor (SRM) has very simple structure and robustness. Generally, for driving SRM, several (6-8) switching devices are required. This is weakpoint for reducing the cost of SRM drive. In This paper, we simulate the single phase and three phase SRM, and we compare the performance or single phase SRM with that of three phase SRM through experiment. Finally we suggest the appropriate application of single phase SRM.

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Analysis of Reduction Effect of Three Harmonic Currents by Zigzag Wiring of Single Phase Transformer (단상 변압기 지그재그 결선에 의한 3고조파 전류 저감 효과 분석)

  • Kim, Jong-Gyeum;Kim, Ji-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.3
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    • pp.99-104
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    • 2017
  • The three-phase four-wire power distribution system can be used to supply power to single-phase and three-phase loads at the same time. There are linear loads and nonlinear loads as single-phase loads connected to each phase. The nonlinear load generates a harmonic current during the power energy conversion process. In particular, the single-phase nonlinear load has a higher proportion of generation of the third harmonic current than the harmonics of the other orders. In a three-phase four-wire system, the third harmonic current flows through the neutral wire to the power supply side, affecting the power supply side and the line. Furthermore, the magnitude of the current flowing in the neutral line can be higher than the current flowing in the individual phase. If the neutral current is higher than the phase current, the breaker may be blocked. Therefore, it is necessary to reduce the amount of current flowing in the neutral line by harmonics. There is a method of zigzag connecting a single phase transformer by a method of reducing 3 harmonic current. In this study, the method of reducing the magnitude of the three harmonic currents flowing through the zigzag wire by comparing the polarity and the negative polarity characteristics of the single phase transformer was compared through measurement and simulation.

Single-phase Active Power Filter Based on Rotating Reference Frame Method for Harmonics Compensation

  • Kim, Jin-Sun;Kim, Young-Seok
    • Journal of Electrical Engineering and Technology
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    • v.3 no.1
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    • pp.94-100
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    • 2008
  • This paper presents a new control method of single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. To facilitate the possibility of complex calculation for harmonic current detection of the single phase, a single-phase system that has two phases was constructed by including an imaginary second-phase giving time delay to the load current. The imaginary phase, which lagged the load current T/4 (Here T is the fundamental cycle) is used in the conventional method. But in this proposed method, the new signal as the second phase is delayed by the filter. Because this control method is applied to a single-phase system, an instantaneous calculation was developed by using the rotating reference frames synchronized to source-frequency rather than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF for the current source with R-L loads is applied to a laboratory prototype to verify the proposed control method.

The speed control of the Single-Phase induction motor using P-I controller (비례 - 적분 제어기를 이용한 단상 유도 전동기의 속도 제어)

  • Sang, Doo-Whan;Cheong, Dal-Ho;Kim, Jung-Chul;Oh, Min-Jin
    • Proceedings of the KIEE Conference
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    • pp.603-605
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    • 1994
  • The Single-Phase induction motor is widely used in home appliances, especially refrigerator, air conditioner and washing machine. Recently many home appliances that use the motor require the speed control to get the various and convenient functions for the customers. Generally it is so hard to control the speed of the Single-Phase induction motor and to get the wide range of the speed variation. In this raper, the speed controller using P-I is designed for the Single-Phase induct ion Motor. The experimental results of the phase controller using P-I show the wide speed control of the Single-Phase induction motor and rebuff control to load change.

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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.

Design of DC Battery Size & Controller for Household Single-Phase ESS-PCS Considering Voltage Drop and DC Link Voltage Ripple (주택용 단상 ESS-PCS의 전압손실과 직류링크 맥동을 고려한 직류측 배터리 사이즈 및 제어기 설계)

  • Kim, Yong-Jung;Lee, Jinsung;Kim, Hyosung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.2
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    • pp.94-100
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    • 2018
  • Generally, in a single-phase energy storage system (ESS) for households, AC ripple component with twice the fundamental frequency exists inevitably in the DC link voltage of single-phase PCS. In the grid-connected mode of a single-phase inverter, the AC ripple component in the DC link voltage causes low-order harmonics on grid-side current that deteriorates power quality on an AC grid. In this work, a control system adopting a feedforward controller is established to eliminate the AC ripple interference on the DC link side. Optimal battery nominal voltage design method is also proposed by considering the voltage loss and AC ripple voltage on DC link side in a single-phase ESS. Finally, the control system and battery nominal voltage design method are verified through simulations and experiments.

Simulink-based Modelling and Simulation for a Single-phase UPFC (Simulink를 이용한 단상 UPFC 모델링 및 시뮬레이션)

  • Kang, Moon-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.3
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    • pp.523-530
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    • 2009
  • This paper presents a study on a small scale single-phase UPFC preliminary researches on power quality compensating schemes of electrical railway. As the UPFC is very complicated power-electronic system consisting of grid-connected transformers, four single phase inverters interconnected with dc-link capacitors and various electrical apparatuses, multiple controllers and control algorithms are needed, and entire UPFC has been modelled in the form of block diagrams and simulated by using Simulink. The main purpose of the compensating system is to manage reactive and active powers with the four single phase inverters, so, the control effort has been focused on the power flow control and has been realized through the hysteresis current control of the single phase inverters. And transport-delayed PLL with additional delay-time compensating term has been used to synchronize a grid voltage and the simulation results have shown that the compensating term could improve PLL performance under some frequency variation of the voltage.

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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The Advanced Protection Coordination Scheme using Phase Angle of Zero-Sequence Current in Ungrounded System (비접지 계통에서 영상전류 위상을 이용한 개선된 보호협조 방안)

  • Choi, Young-Jun;Lim, Hee-Taek;Choi, Myeon-Song;Lee, Seung-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.19-25
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    • 2010
  • Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. The protection coordination method using SGR(Selective Ground Relay) and OVGR(Overvoltage Ground Relay) is generally used in ungrounded system. But this method only detects fault line and it has the possibility of malfunction. This paper proposed to advanced protection coordination method in ungrounded system. The method just using zero-sequence current can detect fault line, fault phase, fault section at terminal device. The general protection method is used to back up protection. In the case study, the proposed method has been testified in demo system by Matlab/Simulink simulations.