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Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)Communication-based distributed secondary control is deemed necessary to restore the state of islanding AC microgrids to set points. As its limited global information, the microgrids become vulnerable to cyber-attacks, which by falsifying the communicating singles, like the angular frequency, can disturb the power dispatch in the microgrids...journal article 2024
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Purgat, P. (author), Shekhar, A. (author), Qin, Z. (author), Bauer, P. (author)Low-voltage direct current (LVdc) systems are a promising technology for systems with a high penetration of renewable sources and storage that operate with bidirectional power flow. In this article, a fundamental building block for LVdc is presented for different applications, such as charge controllers, voltage regulation in street-lighting...journal article 2023
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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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Wu, Y. (author), Qin, Z. (author), Soeiro, Thiago B. (author), Bauer, P. (author)With the great emphasis from the international standard-setting community on the so-called supra-harmonics emissions (2-150 kHz), there are increasing research efforts in this noise level identification, measurement, standard setting and mitigation. The periodic variable switching frequency PWM method, which is known as VSFPWM, can reshape the...conference paper 2023
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Lyu, D. (author), Straathof, C.A. (author), Soeiro, Thiago B. (author), Qin, Z. (author), Bauer, P. (author)This paper proposes two modulation schemes for Dual Active Bridge (DAB) converters, with the aim of maximizing Zero Voltage Switching (ZVS) operation over a wide operational range. The first is a ZVS-optimized constant frequency modulation scheme, constructed based on the boundary conditions of ZVS operation. This scheme maximizes the number...journal article 2023
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Yu, Haoyuan (author), Zhang, Hanwen (author), Wang, Yanbo (author), Qin, Z. (author), Chen, Zhe (author), Bauer, P. (author)This article investigates the stability of triple active bridge (TAB) converter with different types of loads. In this paper, port2 of TAB converter adopts voltage control to supply a constant power load (CPL), and port3 uses voltage control to supply a resistor or uses current control to supply a battery. Then, an extra element theorem-based ...conference paper 2023
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Guan, H. (author), Wu, Y. (author), Qin, Z. (author), Bauer, P. (author)The electric vehicle (EV) market is expanding rapidly. However, the main barriers to EV adoption are high vehicle costs, range issues, and charging infrastructure. Meanwhile, energy storage systems (ESS) appear as a promising solution to preventing grid overload during charging and reducing infrastructure costs. In this paper, the integration of...conference paper 2023
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Mirzadarani, R. (author), Ghaffarian Niasar, M. (author), Li, Z. (author), Qin, Z. (author), Vaessen, P.T.M. (author), Bauer, P. (author), Van Lieshout, Lou (author)Green hydrogen production uses renewable energies to energise the electrolysers for hydrogen production. The present paper compares possible solutions and configurations of a medium-frequency transformer (MFT) as part of a solid-state transformer (SST) in green hydrogen production applications. The single-phase and three-phase MFTs are compared...conference paper 2023
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Liao, Jianquan (author), Zhou, Niancheng (author), Qin, Z. (author), Wang, Qianggang (author), Bauer, P. (author)The unbalanced power between positive and negative poles in a bipolar DC distribution network (DC-DN) generates an unbalanced current at the neutral line, which enlarges the power losses of the system and the voltage deviation of DC loads. An unbalanced power suppression strategy based on a series-parallel power flow controller (SP-PFC) is...journal article 2023
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Lyu, D. (author), Straathof, C.A. (author), Soeiro, Thiago B. (author), Qin, Z. (author), Bauer, P. (author)A variable switching frequency modulation for the Dual Active Bridge (DAB) converter is proposed in this paper. With this variable switching frequency modulation, the DAB converter can be operated in the ZVS-beneficial operational modes without the necessity to transition to others, thus a larger ZVS range for the DAB converter can be...conference paper 2023
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Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)In multi-inverter parallel connected islanded micro-grids, reactive power sharing is challenged by the differences in feeder impedance and various controller parameters. In order to address this issue, a virtual impedance reshaping strategy based on the consensus algorithm is proposed in this paper. The proposed method facilitates adaptive...conference paper 2023
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Wu, Y. (author), Qin, Z. (author), Soeiro, Thiago B. (author), Bauer, P. (author)The sinusoidal Triangular-Current-Mode (S-TCM) method has been proposed in the AC/DC power-factor-correction (PFC) converter to achieve the zero-voltage-switching (ZVS) which can lead to both, high efficiency operation and a high power density design. Nevertheless, the necessary wide range variation of the sinusoidal switching frequency...conference paper 2023
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Wang, L. (author), Qin, Z. (author), Wu, Y. (author), Bauer, P. (author)Reinforcement of the legacy grid infrastructure will be very costly and thereby unrealistic. Consequently, weak grid connection of electric vehicle (EV) chargers will sooner or later be the case. It may however bring instability issues since the EV chargers that can work well in strong grid conditions usually do not fit the weak grid...conference paper 2023
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Li, Z. (author), Qin, Z. (author), Mirzadarani, R. (author), Ghaffarian Niasar, M. (author), Itraj, M.S. (author), Van Lieshout, Lou (author), Bauer, P. (author)For electrolyzer applications, traditional solutions using line frequency transformers plus rectifiers are bulky, heavy and have low controllability. The Solid State Transformer (SST) could be a promising solution to solve the mentioned issues. This paper compares the semiconductor ratings and capacitance of five different Modular Multilevel...conference paper 2023
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Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)This paper proposes a virtual impedance reshaping strategy to share active and harmonic power while promoting the PCC voltage quality. Moreover, the suggested method is resilient to cyber-attacks and immune to communication interruption and delay. Furthermore, it significantly reduces the communication burden. Experiments verify the...conference paper 2023
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Sinha, P. (author), Yadav, S. (author), Qin, Z. (author), Bauer, P. (author)Series-connected MOSFETs with lower voltage ratings can be an alternative for single high-voltage switches. This paper compares two switch configurations for the soft-switched power converter topology targeted for a 1400V DC grid. The first configuration is a single switch rated at 1700V whereas the other is a series connected two MOSFETs rated...conference paper 2023
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Wang, L. (author), Qin, Z. (author), Xiao, J. (author), Bauer, P. (author)The critical short circuit ratio (CSCR), as an important metric for grid stability evaluation, is not clearly defined in the literature. Aimed at clarifying the misunderstandings, the paper compares the different CSCR definitions. Moreover, CSCR reduction-oriented design is studied for electric vehicle chargers. Simulations verify the analysis.conference paper 2023
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- Yadav, S. (author), Qin, Z. (author), Bauer, P. (author) journal article 2022
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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
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Beloqui Larumbe, L. (author), Qin, Z. (author), Bauer, P. (author)In this article, the Linear Time Invariant (LTI) and Linear Time Periodic (LTP) models of two different implementations of the DDSRF-PLL in the presence of voltage imbalance are derived analytically. The accuracy of the models is investigated with time domain simulations, frequency scans, and stability analysis. On top of this, a guideline for...journal article 2022