• Title, Summary, Keyword: Common-mode current detection

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Metamaterial CRLH Structure-based Balun for Common-Mode Current Indicator

  • Kahng, Sungtek;Lee, Jinil;Kim, Koon-Tae;Kim, Hyeong-Seok
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.301-306
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    • 2014
  • We proposed a new PCB-type 'common-mode current($I_c$) and differential-mode current($I_d$) detector' working for fast detection of $I_c$ and $I_d$ from the differential-mode signaling, with miniaturization effect and possibility of cheaper fabrication. In order to realize this device, we suggest a branch-line-coupler balun having a composite right- and left-handed(CRLH) one-layer microstrip phase-shifting line as compact as roughly ${\lambda}_g/14$. The presented balun obviously is different from the conventional bent-&-folded delay lines or slits on the ground for coupling the lines on the top and bottom dielectrics. As we connect the suggested balun output ports of the differential-mode signal lines via the through-port named U and coupled-port named L, $I_c$ and $I_d$ will appear at port ${\Delta}$ and port ${\Sigma}$ of the present device, in order. The validity of the design scheme is verified by the circuit-and numerical electromagnetic analyses, and the dispersion curve proving the metamaterial characteristics of the geometry. Besides, the examples of the $I_c$ and $I_d$ indicator are observed as the even and odd modes in differential-mode signal feeding. Also, the proposed device is shown to be very compact, compared with the conventional structure.

Anti-islanding Detection of Photovoltaic Inverter Based on Negative Sequence Voltage Injection to Grid (역상분 전압 주입을 이용한 태양광 인버터의 단독 운전 검출)

  • Kim, Byeong-Heon;Park, Yong-Soon;Sul, Seung-Ki;Kim, Woo-Chull;Lee, Hyun-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.6
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    • pp.546-552
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    • 2012
  • This paper presents an active anti-islanding detection method using negative sequence voltage injection to the grid through a three-phase photovoltaic inverters. Because islanding operation mode can cause a variety of problems, the islanding detection of grid-connected photovoltaic inverter is the mandatory feature. The islanding mode is detected by measuring the magnitude of negative sequence impedance calculated by the negative sequence voltage and current at the point of common coupling. Simulation and experimental test are performed to verify the effectiveness of the proposed method which can detect the islanding mode in the specified time. The test has been done in accordance with the condition on IEEE Std 929-2000.

Direct Harmonic Voltage Control Strategy of Shunt Active Power Filters Suitable for Microgrid Applications

  • Munir, Hafiz Mudassir;Zou, Jianxiao;Xie, Chuan;Li, Kay;Younas, Talha;Guerrero, Josep M.
    • Journal of Power Electronics
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    • v.19 no.1
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    • pp.265-277
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    • 2019
  • The application of shunt active power filters (S-APFs) is considered to be the most popular approach for harmonic compensation due to its high simplicity, ease of installation and efficient control. Its functionality mainly depends upon the rapidness and precision of its internally built control algorithms. A S-APF is generally operated in the current controlled mode (CCM) with the detection of harmonic load current. Its operation may not be appropriate for the distributed power generation system (DPGS) due to the wide dispersion of nonlinear loads. Despite the fact that the voltage detection based resistive-APF (R-APF) appears to be more appropriate for use in the DPGS, the R-APF experiences poor performance in terms of mitigating harmonics and parameter tuning. Therefore, this paper introduces a direct harmonic voltage detection based control approach for the S-APF that does not need a remote harmonic load current since it only requires a local point of common coupling (PCC) voltage for the detection of harmonics. The complete design procedure of the proposed control approach is presented. In addition, experimental results are given in detail to validate the performance and superiority of the proposed method over the conventional R-APF control. Thus, the outcomes of this study approve the predominance of the discussed strategy.

A Low Noise Low Power Capacitive Instrument Amplifier for Bio-Potential Detection (생체 신호 측정용 저 잡음 저 전력 용량성 계측 증폭기)

  • Park, Chang-Bum;Jung, Jun-Mo;Lim, Shin-Il
    • Journal of Sensor Science and Technology
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    • v.26 no.5
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    • pp.342-347
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    • 2017
  • We present a precision instrument amplifier (IA) designed for bio-potential acquisition. The proposed IA employs a capacitively coupled instrument amplifier (CCIA) structure to achieve a rail-to-rail input common-mode range and low gain error. A positive feedback loop is applied to boost the input impedance. Also, DC servo loop (DSL) with pseudo resistors is adopted to suppress electrode offset for bio-potential sensing. The proposed amplifier was designed in a $0.18{\mu}m$ CMOS technology with 1.8V supply voltage. Simulation results show the integrated noise of $1.276{\mu}Vrms$ in a frequency range from 0.01 Hz to 1 KHz, 65dB SNR, 118dB CMRR, and $58M{\Omega}$ input impedance respectively. The total current of IA is $38{\mu}A$. It occupies $740{\mu}m$ by $1300{\mu}m$ including the passive on-chip low pass filter.