• Title/Summary/Keyword: frequency-phase method

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Power Decoupling Control of the Bidirectional Converter to Eliminate the Double Line Frequency Ripple (더블라인 주파수 제거를 위한 양방향 컨버터의 전력 디커플링 제어)

  • Amin, Saghir;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • 2018.11a
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    • pp.62-64
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    • 2018
  • In two-stage single-phase inverters, inherent double line frequency component is present at both input and output of the front-end converter. Generally large electrolytic capacitors are required to eliminate the ripple. It is well known that the low frequency ripple shortens the lifespan of the capacitor hence the system reliability. However, the ripple can hardly be eliminated without the hardware combined with an energy storage device or a certain control algorithm. In this paper, a novel power-decoupling control method is proposed to eliminate the double line frequency ripple at the front-end converter of the DC/AC power conversion system. The proposed control algorithm is composed of two loop, ripple rejection loop and average voltage control loop and no extra hardware is required. In addition, it does not require any information from the phase-locked-loop (PLL) of the inverter and hence it is independent of the inverter control. In order to prove the validity and feasibility of the proposed algorithm a 5kW Dual Active Bridge DC/DC converter and a single-phase inverter are implemented, and experimental results are presented.

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Characteristics analysis of time sharing method VVVF type high frequency resonant inverter (시분할 방식 VVVF형 고주파 공진 인버터의 특성해석)

  • 조규판;원재선;남승식;심광렬;배영호;김동희
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.3
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    • pp.20-28
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    • 2002
  • This paper describes the time sharing type high frequency resonant inviter can be used as power of induction heating. This closed inverter can be obtained output frequency three times than switching frequency by composing three unit inviter of conventional Half-Bridge serial resonant inverter in parallel with input power source also, this reduce switching loss because it has ZVS function. The analysis of the proposed circuit is generally described by using the normailized proposed parameters. The principle of basic operating and the its charasteristics are extimated by the parameters such as switching frequency($\mu$), the variation of Phase angle($\phi$) of Phase-shift. Experimental results are presented to verify theoretical discussion. This preposed inverter will be able to be prastically used as a power supply in various fields as induction, heating application, DC-DC converter etc.

An Active Cancellation Method for the Common Mode Current of the Three-Phase Induction Motor Drives (3상 유도전동기 구동장치의 동상모드 전류 능동 제거법)

  • Uzzaman, Tawfique;Kim, Unghoe;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • 2019.11a
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    • pp.96-97
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    • 2019
  • Pulse Width Modulation (PWM) is a widely adopted technique to drive the motor using the voltage source inverters. Since they generate high frequency Common Mode (CM) Voltage, a high shaft voltage in induction motor is induced which leads to parasitic capacitive currents causing adverse effects such as premature deterioration of ball bearings and high levels of electromagnetic emissions. This paper presents an Active Cancellation Circuit (ACC) which can significantly reduce the CM voltage hence the common mode current in the three phase induction motor drives. In the proposed method the CM voltage is detected by the capacitors and applied to the frame of the motor to cancel the CM voltage hence the CM current. Unlike the conventional methods the proposed method does not insert the transformer in between the inverter and motor, a high power rating three phase transformer is not required and no losses associated with it. In addition the proposed method is applicable to any kind of PWM motor drives regardless of their PWM methods. The effectiveness of the proposed method is proved by the experiments with a three phase induction motor (1.1kW 415V/60Hz) combined with a three phase voltage source inverter modulated by the Space Vector Modulation (SVM).

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Input Impedance and Current Feedforward Control of Single-Phase Boost PFC Converters

  • Park, Sungmin;Park, Sung-Yeul;Bazzi, Ali M.
    • Journal of Power Electronics
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    • v.15 no.3
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    • pp.577-586
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    • 2015
  • The combination of voltage feedforward and feedback control is a conventional approach for correcting the power factor in single-phase ac-dc boost converters. The feedback duty ratio increases significantly with an increase of the line frequency and input inductance. Therefore, the performance of the conventional approach is highly dependent on the bandwidth of the feedback controller. As a result, the input power quality can be significantly exacerbated due to uncompensated duty ratios if the feedback controller is limited. This paper proposes an input impedance and current feedforward control method to reduce the control portion of the feedback controller. The findings in this paper are 1) the theoretical derivation and analysis of variations of line frequency and input inductance on a power factor correction approach, 2) guaranteed consistent performance in a wide range of conditions, and 3) that a low switching frequency can be utilized by the proposed method. A MATLAB/Simulink model and a 1.2kW dual boost converter are built to demonstrate the effectiveness of the proposed method.

Method Based on Sparse Signal Decomposition for Harmonic and Inter-harmonic Analysis of Power System

  • Chen, Lei;Zheng, Dezhong;Chen, Shuang;Han, Baoru
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.559-568
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    • 2017
  • Harmonic/inter-harmonic detection and analysis is an important issue in power system signal processing. This paper proposes a fast algorithm based on matching pursuit (MP) sparse signal decomposition, which can be employed to extract the harmonic or inter-harmonic components of a distorted electric voltage/current signal. In the MP iterations, the method extracts harmonic/inter-harmonic components in order according to the spectrum peak. The Fast Fourier Transform (FFT) and nonlinear optimization techniques are used in the decomposition to realize fast and accurate estimation of the parameters. First, the frequency estimation value corresponding to the maxim spectrum peak in the present residual is obtained, and the phase corresponding to this frequency is searched in discrete sinusoids dictionary. Then the frequency and phase estimations are taken as initial values of the unknown parameters for Nelder-Mead to acquire the optimized parameters. Finally, the duration time of the disturbance is determined by comparing the inner products, and the amplitude is achieved according to the matching expression of the harmonic or inter-harmonic. Simulations and actual signal tests are performed to illustrate the effectiveness and feasibility of the proposed method.

All-fiber heterodyne interferometer with phase modulation (Mach-Zehnder 광섬유 간섭계를 이용한 Heterodyne 검파 방법)

  • Jeong, Kyu-Cheol;Song, Jung-Tae;Lee, Kyung-Shik
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.996-998
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    • 1998
  • We have proposed and demonstrated a novel method of heterodyne detection using all-fiber Mach-Zehnder interferometer. The method is characterized by the phase modulation with a sawtooth waveform instead of a frequency modulation in true heterodyne. The experimental results will be compared with the expected results.

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Design of Input.Output Filter of Single Multifunctional UPS (단상 다기능 UPS 입.출력 필터 설계)

  • 김제홍
    • Proceedings of the IEEK Conference
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    • 2002.06e
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    • pp.307-310
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    • 2002
  • A design for the input filter and the output filter of a single-phase UPS system is proposed. And also, this paper describes a reduction of the DC voltage ripple of a single-phase UPS. The input power of proposed UPS fluctuates with twice frequency of the utility source, which causes DC voltage fluctuation. The reduction of the DC voltage fluctuation requires a large DC link capacitor. The proposed method uses a LC series resonant filter paralleled with a conventional smoothing capacitor. The effectiveness of the proposed method was confirmed by simulation results.

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Limit Cycle Analysis Of Attitude Control System Using Thruster Under Time Delay Effect (시간지연을 갖는 추력기 자세제어시스템의 Limit Cycle 분석)

  • 안재명;노웅래;정호락;최형돈
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.3-3
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    • 2000
  • Limit cycle analysis of attitude control system using gas jet thrusters is performed. Schmitt-Trigger and PD control laws are applied and solenoid valve time delay is considered. Phase plane method is used for calculation of characteristics of limit cycle. Important characteristics of resultant limit cycle such as frequency, amplitude, maximum rate, and duty ratio could be expressed analytically by proposed method.

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A Study on the Optimal Tuning of PID Controller (PID 제어기의 최적 동조)

  • 임동균;서병설
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.11
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    • pp.27-36
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    • 1993
  • It is well know that the tuning method of Yuwana-Seborg (1982) can not be even applied to the relatively small delay system due to the phase errors from the Pad approximation suh (1984, 85, 86). Jutan and Rodriguez(1984), lee(1989), Chen(1989), Lee and Edgar(1990), etc have been tried to improve it. In this stydy, such recent results and their problems are investigated. A new tuning method by "a frequency scale transformation". which is based on a previous result of Suh(1984). is proposed. It can reduce the magnitude of the phase error significantly.

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Single-Phase Hybrid Active Power Filter Using Rotating Reference Frame (회전좌표계를 이용한 단상 하이브리드형 능동 전력필터)

  • Kim Jin-Sun;Kim Young-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.8
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    • pp.377-386
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    • 2005
  • This paper presents the control algorithm of single-phase hybrid active power filter for the compensation of harmonic current components in nonlinear R-L load with passive active Power filters. To construct two phase system, an imaginary second phase was made. In this proposed method, the new signal which is the delayed through the filtering by the phase-delay property of low-pass filter is used as the secondary phase. Because two-phases have the different phase, the instantaneous calculation of harmonic current is possible. In this paper, a reference voltage is created by multiplying the coefficient k by the compensation current using the rotating reference frame synchronized with the source-frequency, not applying to instantaneous reactive power theory which has been used with the existing fixed reference frames In order to verify the validities of the proposed control methods, experiments are carried out with the prototypes of single-phase hybrid active power filter.