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Yeongam, South Korea

Jung Y.-G.,Sehan University
Journal of Electrical Engineering and Technology | Year: 2013

The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter/the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case. Source

Lee J.-Y.,Sehan University
2016 International Conference on Platform Technology and Service, PlatCon 2016 - Proceedings | Year: 2016

The purpose of this study is to investigate the general effect of dictogloss, which is an English teaching approach in Korean EFL. Fifty seven research cases from twenty two studies were used in the meta-analysis. Each study was classified in terms of research target participants (elementary, middle, and high school students), treatment period, and dependent variables. Dependent variables were divided into two categories; one is linguistic competence such as listening, reading, speaking, writing, grammar, and vocabulary, and the other is affective domain including interest and confidence. The research results using a meta-analysis suggest that there is a positive effect (g=.511) in the use of dictogloss. © 2016 IEEE. Source

Lim Y.-C.,Chonnam National University | Wi S.-O.,Korea Astronomy and Space Science Institute | Kim J.-N.,Celrun Co | Jung Y.-G.,Sehan University
IEEE Transactions on Power Electronics | Year: 2010

This paper describes a pseudorandom carrier modulation scheme and its harmonic spectra spread effect. The pseudorandom carrier of the proposed scheme are produced through the random synthesis of the two triangular carriers, each of the same fixed frequency, but of opposite phase. The random selection of the two triangular carriers is decided by ''0'' or ''1'' states of the pseudorandom binary sequence (PRBS) random bits. Multiplexer which are used as random selector of the PRBS random bits, produces the resultant pseudorandom frequency carrier waveform. In order to verify the validity of the proposed method, the simulations and experiments were conducted and tested with a single-phase low-power H-bridge multilevel inverter. An EXAR XR2207 is used as a triangular carrier generator with fixed frequency, also an XR2206 is used for generation of single-phase sinusoidal wave. The PRBS random bits generator is implemented, using a shift register and an EXCLUSIVE OR gate. The experimental results show that the harmonics spectra of voltage and current are dispersed over a wide-band area by using the proposed scheme. © 2006 IEEE. Source

Park J.-W.,Sehan University
Advanced Studies in Theoretical Physics | Year: 2014

In this paper, we defined a new q-extension of Bernoulli polynomials with weight by generating function, and investigate several properties of those polynomials. These q-Bernoulli polynomials are useful to study various identities of Carlitz’s qBernoulli numbers. © 2014 Jin-Woo Park. Source

Nguyen M.-K.,Chonnam National University | Jung Y.-G.,Sehan University | Lim Y.-C.,Chonnam National University
IEEE Transactions on Power Electronics | Year: 2010

This paper deals with a new family of single-phase ac-ac converters called single-phase quasi-Z-source ac-ac converters. The proposed converter inherits all the advantages of the traditional single-phase Z-source ac-ac converter, which can realize buck-boost, reversing, or maintaining the phase angle. In addition, the proposed converter has the unique features that the input voltage and output voltage share the same ground and the operation is in the continuous current mode. The operating principles of the proposed converter are described, and a circuit analysis is provided. In order to verify the performance of the proposed converter, a laboratory prototype was constructed with a voltage of 84 Vrms/60 Hz. The simulation and experimental results verified that the converter has a lower input current total harmonic distortion and higher input power factor in comparison with the conventional single-phase Z-source ac-ac converter. © 2010 IEEE. Source

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