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Lijiao Gong,Xinheng Li,Xuewei Chao,Jing Zuo,Yang Li 한국자기학회 2017 Journal of Magnetics Vol.22 No.3
As known, the variation of distances between the adjacent coils will affect the transfer efficiency in magnetic coupled resonance system. In order to explore the influence of distance on the optimum transfer efficiency, a four-coil magnetic coupled resonance system is established. Based on the mutual inductance coupling theory, the relationship between the transfer efficiency and coupling coefficient is obtained. Supported by the simulation analysis and experimental evidences, it is found that the coupling coefficient k23 (between transmitter and receiver coils) is the most significant factor affecting the transfer efficiency. Under the optimal k23, the transfer efficiency will increase with the coupling coefficient k12 (between driver and transmitter coils). Besides, it will firstly increase and then decrease with the coupling coefficient k34 (between receiver and load coils). Moreover, the theoretical calculation formula of k23 is deduced, which can make a contribution to the optimization of parameters and improvement of transfer efficiency for the four-coil magnetic coupled resonance system.
Lijiao Gong,Xinheng Li,Xuewei Chao,Yang Li,Hui Li,Hongwei Li 한국자기학회 2017 Journal of Magnetics Vol.22 No.3
The impedance matching problem of magnetic coupled resonant wireless power transfer system based on planar spiral coils is studied in this paper. Taken the coupling factors into account, the relationships between impedance matching, resonant frequency and transfer distance are analyzed. Supported by the simulation analyses and experimental evidences, it is indicated that the optimum matching resistances for transfer power and transfer efficiency are different. In details, the optimal matching resistance for output power decreases with the transfer distance, while that for the transfer efficiency does not vary with transfer distance. Thus, this research provides a valuable reference for the further research on adaptive impedance matching of magnetic coupled resonant wireless power transfer system.
Development of Fault Location Algorithm and Its Verification Experiments for HVDC Submarine Cables
Jung, Chae-Kyun,Park, Hung-Sok,Kang, Ji-Won,Wang, Xinheng,Kim, Yong-Kab,Lee, Jong-Beom The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.6
A new fault location algorithm based on stationary wavelet transform and its verification experiment results are described for HVDC submarine cables in this paper. For wavelet based fault location algorithm, firstly, 4th level approximation coefficients decomposed by wavelet transform function are superimposed by correlation, then the distance to the fault point is calculated by time delay between the first incident signal and the second reflected signal. For the verification of this algorithm, the real experiments based on various fault conditions and return types of fault current are performed at HVDC submarine cable test yard located in KEPCO(Korea Electric Power Corporation) Power Testing Center of South Korea. It proves that the fault location method proposed in this paper is very simple but very quick and accurate for HVDC submarine cable fault location.
Development of Fault Location Algorithm and Its Verification Experiments for HVDC Submarine Cables
Chae-Kyun Jung,Hung-Sok Park,Ji-Won Kang,Xinheng Wang,Yong-Kab Kim,Jong-Beom Lee 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.6
A new fault location algorithm based on stationary wavelet transform and its verification experiment results are described for HVDC submarine cables in this paper. For wavelet based fault location algorithm, firstly, 4th level approximation coefficients decomposed by wavelet transform function are superimposed by correlation, then the distance to the fault point is calculated by time delay between the first incident signal and the second reflected signal. For the verification of this algorithm, the real experiments based on various fault conditions and return types of fault current are performed at HVDC submarine cable test yard located in KEPCO(Korea Electric Power Corporation) Power Testing Center of South Korea. It proves that the fault location method proposed in this paper is very simple but very quick and accurate for HVDC submarine cable fault location.