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Liu, M. (author), Li, D. (author), Qin, P. (author), Liu, C. (author), Wang, H. (author), Wang, F. (author)
Networks can be used to describe the interconnections among individuals, which play an important role in the spread of disease. Although the small-world effect has been found to have a significant impact on epidemics in single networks, the small-world effect on epidemics in interconnected networks has rarely been considered. Here, we study the...
journal article 2015
document
Qin, Lilong (author), Wu, Manqing (author), Wang, X. (author), Dong, Zhen (author)
Motivated by the sparsity of filter coefficients in full-dimension space-Time adaptive processing (STAP) algorithms, this paper proposes a fast ℓ1-regularized STAP algorithm based on the alternating direction method of multipliers to accelerate the convergence and reduce the calculations. The proposed algorithm uses a splitting variable to...
journal article 2017
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Qin, Z. (author), Shen, Yanfeng (author), Loh, Poh Chiang (author), Wang, Huai (author), Blaabjerg, Frede (author)
A Dual Active Bridge (DAB) converter can achieve a wide high-efficiency range when its input and output voltages are equal, assuming a 1:1 turns ratio for its isolation transformer. If its input or output voltage is doubled, efficiency of the DAB will drop significantly, because of the introduction of hard switching and high circulating power....
journal article 2018
document
Wang, Lu (author), Qin, Z. (author), Dong, J. (author), Bauer, P. (author)
In recent years, electrical vehicle (EV) starts showing its unique advantages that the conventional combustion vehicles do not have. Together with the increasing interests on EV, the motor drive with higher efficiency and lighter weight also becomes more attractive. A promising solution is to apply the wide band gap (WBG) components including...
conference paper 2019
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Shen, Yanfeng (author), Wang, Huai (author), Al Durra, Ahmed (author), Qin, Z. (author), Blaabjerg, Frede (author)
This paper proposes a new series resonant DC-DC converter with four configurable operation states depending on the input voltage and output voltage levels. It suits well for the DC-DC stage of grid-connected photovoltaic (PV) systems with a wide-input voltage range and different grid voltage levels, i.e., 110/120 V and 220/230/240 V. The...
journal article 2019
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Wei, Mingqiang (author), Tian, Yang (author), Pang, Wai-Man (author), Wang, C.C. (author), Pang, Ming-Yong (author), Wang, Jun (author), Qin, Jin (author), Heng, Pheng-Ann (author)
Bas-relief is characterized by its unique presentation of intrinsic shape properties and/or detailed appearance using materials raised up in different degrees above a background. However, many bas-relief modeling methods could not manipulate scene details well. We propose a simple and effective solution for two kinds of bas-relief modeling (i...
journal article 2019
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Cai, Miao (author), Cui, Peng (author), Qin, Yikang (author), Geng, Daoshuang (author), Wei, Qiqin (author), Wang, Xiyou (author), Yang, Daoguo (author), Zhang, Kouchi (author)
Understanding the defect characterization of electronic and mechanical components is a crucial step in diagnosing component lifetime. Technologies for determining reliability, such as thermal modeling, cohesion modeling, statistical distribution, and entropy generation analysis, have been developed widely. Defect analysis based on the...
review 2020
document
Ding, Chao (author), Wang, Jian (author), Liu, Tianhan (author), Qin, Hongbo (author), Yang, Daoguo (author), Zhang, Kouchi (author)
Full intermetallic compound (IMC) solder joints present fascinating advantages in high-temperature applications. In this study, the mechanical properties and elastic anisotropy of η’-Cu6Sn5 and Cu3Sn intermetallic compounds were investigated using first-principles calculations. The values of single-crystal elastic constants, the elastic (E),...
journal article 2021
document
Beloqui Larumbe, L. (author), Qin, Z. (author), Wang, L. (author), Bauer, P. (author)
This article presents a small-signal model for power-electronics converters that use a typical control structure in wind energy applications: the double synchronous reference frame current control. The article considers the presence of unbalanced currents and voltages, and analyzes their impact on the frequency couplings of the converter. In...
journal article 2021
document
Liao, Jianquan (author), Zhou, Niancheng (author), Qin, Z. (author), Purgat, P. (author), Wang, Qianggang (author), Bauer, P. (author)
The two main challenges of medium voltage direct current (MVDC) distribution network are the flexible control of power flow (PF) and fault protection. In this paper, the power flow controller (PFC) is introduced to regulate the PF and inhibit the fault current during the DC fault. The coordination strategy of series-parallel PFC (SP-PFC) and...
journal article 2021
document
Wang, L. (author), Qin, Z. (author), Beloqui Larumbe, L. (author), Bauer, P. (author)
To accurately simulate electric vehicle DC fast chargers' (DCFCs') harmonic emission, a small time step, i.e., typically smaller than 10 μs, is required owing to switching dynamics. However, in practice, harmonics should be continuously assessed with a long duration, e.g., a day. A trade-off between accuracy and time efficiency thus exists. To...
journal article 2021
document
Wang, L. (author), Qin, Z. (author), Slangen, T (author), Bauer, P. (author), van Wijk, T (author)
With growing concern on climate change, widespread adoption of electric vehicles (EVs) is important. One of the main barriers to EV acceptance is range anxiety, which can be alleviated by fast charging (FC). The main technology constraints for enabling FC consist of high-charging-rate batteries, high-power-charging infrastructure, and grid...
journal article 2021
document
Wang, L. (author), Qin, Z. (author), Beloqui Larumbe, L. (author), Bauer, P. (author)
To accurately simulate the harmonic emission of EV DC fast chargers (DCFCs) and the harmonic voltage of the power grid to which the chargers are connected, a small time-step, i.e., typically smaller than 10μs, is required. However, for harmonic assessment, a long timescale, typically a day, is required. A conflict between accuracy and time...
conference paper 2021
document
Wang, Jian (author), Qin, Hongbo (author), Chen, Junfu (author), Yang, Daoguo (author), Zhang, Kouchi (author)
In this study, first-principles calculations were utilized to investigate the lattice constants, elastic constants, and mechanical properties of gold–copper (Au–Cu) intermetallic compounds (IMCs), including AuCu3, AuCu, and Au3Cu. We also verified the direction dependence of the Young’s modulus, shear modulus, and Poisson’s ratio of the...
journal article 2022
document
Sun, S.Z. (author), Wang, Zhenpo (author), Liu, Peng (author), Qin, Z. (author), Chen, Yong (author), Han, Yang (author), Wang, Peng (author), Bauer, P. (author)
Battery fault diagnosis is crucial for stable, reliable, and safe operation of electric vehicles, especially the thermal runaway early warning. Developing methods for early failure detection and reducing safety risks from failing high energy lithium-ion batteries has become a major challenge for industry. In this article, a real-time early...
journal article 2022
document
Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)
Smart grid steady control relies heavily on the communication infrastructure among sensors, actuators, and control systems, which makes it vulnerable to cyber-attacks. Accurate acquisition of dynamic state information is deemed vital for efficient detection of these cyber-attacks on a smart grid. However, several popular state estimation...
conference paper 2022
document
Qin, Z. (author), Wang, L. (author), Bauer, P. (author)
Electric vehicles (EVs) are playing a crucial role in achieving the carbon neutral goal. To make the charging experience comparable with the refueling of the gasoline cars, more and more chargers are installed and connected to the grid. Meanwhile, the charging power is going up. As a result, more and more power quality issues associated with EV...
conference paper 2022
document
Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)
Distributed secondary control is deemed necessary to restore the state of AC micro-grids to set points. However, for its limited global information, the power electronic system is vulnerable to cyber-attacks that aim to desynchronize converters or even cause a shutdown of micro-grids by unnecessarily triggering the protection schemes. To this...
conference paper 2022
document
Liang, Y. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)
In emerging fast-charging stations, DC fast chargers (DCFCs) are employed which rely on power electronics and control to achieve the required performance. Harmonic emission induced by the complex system behavior is of great concern in the DCFC system. This paper proposes a harmonic emission model for the typical electric vehicle charger...
conference paper 2022
document
Wang, L. (author), Qin, Z. (author), Bauer, P. (author)
Extracting an electric vehicle (EV) charger's input impedance with the analytical model (white-box approach) or the frequency sweep (black-box approach) is limited by the parameter confidentiality or the measurement noise, respectively. To overcome these challenges, a gradient-descent (GD) optimization-based gray-box modeling approach is...
journal article 2023
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