• Title/Summary/Keyword: Linear current source

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Stability improvement of induction motor vector control system without speed sensor

  • Tsuji, Mineo;Li, Hanqiang;Izumi, Katsuhiro;Yamada, Eiji
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.207-210
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    • 1995
  • In this paper, two representative schemes for vector control of induction motor without speed sensor are studied. First, the two sensorless systems which are implemented by voltage and current source are presented with new ideas and interpretations. Then a linear model around an operating point is proposed. Finally, the stability improvement of these systems are studied and evaluated by computing the trajectories of poles and zeros.

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Active Disturbance Rejection Control for Single-Phase PWM Rectifier with Current Decoupling Control

  • Yan, Ruitao;Wang, Ping
    • Journal of Electrical Engineering and Technology
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    • v.13 no.6
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    • pp.2354-2363
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    • 2018
  • This paper proposed a novel double closed control strategy for single-phase voltage source pulse width modulation (PWM) rectifier based on active disturbance rejection control (ADRC) and dq current decoupling control. First, the mathematical model of the single-phase PWM rectifier in the d-q axis synchronous rotating reference frame is established by constructing a virtual component using a second-order generalized integrator (SOGI). Then, the mathematical model is simplified according to the active power conservation, and the first-order equation of single-phase PWM rectifier voltage outer loop is acquired. A linear auto-disturbance rejection controller is used to design the voltage outer loop according to the first-order equation. Finally, the proposed control strategy and the traditional PI control are compared and verified by simulation and physical experiments. Both simulation and experimental results confirm that the proposed control strategy has excellent dynamic performance and strong rejection ability to disturbances.

A Study on the Secondary Side Eddy Current Distribution Analysis of a Short Primary-Short Secondary Single-Sided LIM by the Finite Element Method (단1차 단2차 편측식 선형 유도전동기의 유한요소법에 의한 2차측 와전류 분포해석에 관한 연구)

  • 임달호;조윤현
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.5
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    • pp.453-461
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    • 1990
  • In this paper, a short primary-short secondary single-sided linear induction motor which is used as the driving source for an automatic conveyor system, is selected as an analysis model. The finite element method in which the current vector potential is introduced is adopted to analyze the eddy current distribution and thrust force which are produced according to the relative position of the primary and the secondary. Also, the analysis results are compared with experimental ones, to show the propriety of this model.

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An Implementation of Efficient Error-reducing Method Using DSP for LED I-V Source and Measurement System (DSP를 이용한 LED I-V 공급 및 측정 시스템에서의 효율적인 오차 감소 기법 구현)

  • Park, Chang Hee;Cho, Sung Ho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.12
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    • pp.109-117
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    • 2015
  • In this paper, we proposed error-reducing method to source or measure a current or voltage for LED in the I-V characteristic analysis system using a digital signal processor (DSP). this method has the advantage of reducing a non-linear circuit error and random error. random error can be reduced using recursive averaging technique and non-linear circuit error can be reduced using 2rd polynomial regression calibration parameters fitting with measured sample data. it corrects measured error of IR, VR, VF1, VF2, VF3 of LED using calibration parameters. experimental results show that can be performed with about 0.017~0.043% accuracy.

Compensating algorithm for a measurement type CT considering hysteresis characteristic of the core (히스테리시스 특성을 고려한 측정용 변류기 보상 알고리즘)

  • Kang, Yong-Cheol;Zheng, Taiying;Lee, Byung-Eun;So, Soon-Hong;Lee, Hyun-Woong;Lee, Mi-Sun;Park, Jung-Ho;Choi, Hyun-Tae;Jang, Sung-Il;Kim, Yong-Gyun
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.44-45
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    • 2007
  • This paper deals with error compensation in current transformers. Since the exciting current can be considered as the main error source, its evaluation can allow the compensation of its detrimental effects to be obtained. The exciting current required by the transformer in every king of steady state operation can be determined by simply acquiring the secondary current, provided that the examined CT has been preliminarily identified. This paper also proposed a new approach to the model of the exciting branch. The exciting branch can be divided into a non-linear core loss resistor, and a non-linear magnetizing inductor whose flux and current characteristic is not the same as the characteristic shown by the joined tips of the first quadrant of a family of hysteresis loops. The performance of the proposed algorithm was validated under various conditions using EMTP generated data. Test result show, in all cases an improvement in primary current reproduction accuracy, compared with that achieved using CT's ratio.

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Application of an Optical Current Transformer For Measuring High Current

  • Kim, Yeong-Min;Park, Won-Zoo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.11
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    • pp.9-16
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    • 2010
  • This paper examines the temperature characteristics of an Optical CT (optical current transformer) using the Faraday effect for measuring high current in a super high voltage-power apparatus. It is performed as follows by the sensor for embodying Faraday effect. $\cdot$ A single-mode optical fiber capable of maintaining a polarization state is used. $\cdot$ A light source is applied at 1310[nm] to a Laser Diode. $\cdot$ The Linear of Faraday effect to a large current is evaluated and $\cdot$ A possible application using an Optical CT was shown. An Influence of Faraday effect to the surrounding temperature measured -40~50[$^{\circ}C$], and the characteristic of the current sensitivity was reported. An application using the results of the temperature compensation system was used in order to compensate for surrounding temperatures. A possibility of applying Optical CT for electric power apparatus was advanced further. We were able to confirm that this temperature calibration method can minimize the fluctuation of the output signal depending on the temperature conditions.

Inrush Current Suppression Method of the Reactive Power Compensator by using a Linear Region of the Switch (스위치의 선형영역을 이용한 무효전력보상기의 돌입전류 억제 방안)

  • Park, Seong-Mi;Kang, Seong-Hyun;Park, Sung-Jun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.3
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    • pp.55-64
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    • 2013
  • In this paper, a new topology which can add a small reactor in series to a condenser-bank type reactive power compensator to limit current is proposed. And also the proposed topology can add or remove a power condenser safely without any addition of inrush-current suppression resistance. The proposed method tests variable resistance of the drain source of a switching device which is controlled by gate voltage in a two-way switch with a diode rectifier and FET switch. In other words, the proposed method is a inrush-current suppression method with the structure of variable resistance. In particular, the proposed method creates smooth current without any resonance in inrush-current as well as is not limited by the time of switch on and off.

Design and Implementation of Solar PV for Power Quality Enhancement in Three-Phase Four-Wire Distribution System

  • Guna Sekar, T.;Anita, R.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.75-82
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    • 2015
  • This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

The effect of 1/f Noise Caused by Random Telegraph Signals on The Phase Noise and The Jitter of CMOS Ring Oscillator (Random Telegraph Signal에 의한 1/f 잡음이 CMOS Ring Oscillator의 Phase Noise와 Jitter에 미치는 영향)

  • 박세훈;박세현;이정환;노석호
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05b
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    • pp.682-684
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    • 2004
  • The effect of 1/f noise by the random telegraph signal(RTS) on the phase noise and the jitter of CMOS ring Oscillator is investigated. 10 parallel piece-wise-linear current sources connected to each node model the RTS signals. The In, the power spectral density and the jitter of output of the ring oscillator are simulated as functions of the amplitude and time constant of RTS current source. It is confirmed that the increase of amplitude of RTS is directly related to the increase of the width of phase noise md the value of jitter. The shorter the time constant is, the wider width of FET peak and the larger value of cycle to cycle jitter are.

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Nonlinear Motion Responses for A Moored Ship beside Quay (안벽에 계류된 선박에 대한 비선형 운동응답)

  • Lee, Ho-Yooung;Lim, Choon-Gyu;Lew, Jae-Moon;Chun, In-Sik
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.172-178
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    • 2003
  • As a typoon gets into harbour, a moored ships shows erratic motions and even mooring line failures is occurred. Such troubles may be caused by harbour resonance phenomena, result in large motion amplitudes at law frequency, which is closed to the natural frequency of the moored ship. The nonlinear motions of a moored ship beside quay are simulated under external forces due to wave, current including mooring forces in time domain. The forces due to waves are obtained from source and dipole distribution method in the frequency domain. The current forces are calculated by using slow motion maneuvering equation in the horizontal plane. The wind forces are calculated from emperical formula of ABS and the mooring forces of ropes and fenders are modeled as linear spring.

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