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RISS 인기검색어
- 검색키워드
- 저자 : Peifeng Xu (검색결과 5 건)
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Grid-Connected Dual Stator-Winding Induction Generator Wind Power System for Wide Wind Speed Ranges
Shi, Kai,Xu, Peifeng,Wan, Zengqiang,Bu, Feifei,Fang, Zhiming,Liu, Rongke,Zhao, Dean The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4
This paper presents a grid-connected dual stator-winding induction generator (DWIG) wind power system suitable for wide wind speed ranges. The parallel connection via a unidirectional diode between dc buses of both stator-winding sides is employed in this DWIG system, which can output a high dc voltage over wide wind speed ranges. Grid-connected inverters (GCIs) do not require booster converters; hence, the efficiency of wind energy utilization increases, and the hardware topology and control strategy of GCIs are simplified. In view of the particularities of the parallel topology and the adopted generator control strategy, we propose a novel excitation-capacitor optimization solution to reduce the volume and weight of the static excitation controller. When this excitation-capacitor optimization is carried out, the maximum power tracking problem is also considered. All the problems are resolved with the combined control of the DWIG and GCI. Experimental results on the platform of a 37 kW/600 V prototype show that the proposed DWIG wind power system can output a constant dc voltage over wide rotor speed ranges for grid-connected operations and that the proposed excitation optimization scheme is effective.
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Grid-Connected Dual Stator-Winding Induction Generator Wind Power System for Wide Wind Speed Ranges
Kai Shi,Peifeng Xu,Zengqiang Wan,Feifei Bu,Zhiming Fang,Rongke Liu,Dean Zhao 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4
This paper presents a grid-connected dual stator-winding induction generator (DWIG) wind power system suitable for wide wind speed ranges. The parallel connection via a unidirectional diode between dc buses of both stator-winding sides is employed in this DWIG system, which can output a high dc voltage over wide wind speed ranges. Grid-connected inverters (GCIs) do not require booster converters; hence, the efficiency of wind energy utilization increases, and the hardware topology and control strategy of GCIs are simplified. In view of the particularities of the parallel topology and the adopted generator control strategy, we propose a novel excitation–capacitor optimization solution to reduce the volume and weight of the static excitation controller. When this excitation–capacitor optimization is carried out, the maximum power tracking problem is also considered. All the problems are resolved with the combined control of the DWIG and GCI. Experimental results on the platform of a 37 kW/600 V prototype show that the proposed DWIG wind power system can output a constant dc voltage over wide rotor speed ranges for grid-connected operations and that the proposed excitation optimization scheme is effective.
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Shi, Kai,Li, Tong,Ren, Mingwei,Xu, Peifeng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.5
Virtual synchronous generators (VSGs), with the operational characteristics of synchronous generators (SGs), have been employed in renewable energy generation grid-connected systems to solve the problem of insufficient equivalent inertia, which is caused by the high permeability of distributed generation systems in the grid. However, a VSG does not possess low voltage ride-through (LVRT) capability. A novel LVRT control strategy for a VSG based on virtual self-inductive flux linkage is proposed in this paper. First, the electromagnetic transient response mechanism of a SG under grid faults is analyzed in detail. Then, a memory and retention strategy are proposed to simulate the effect of the switch law. Furthermore, the virtual q-axis armature self-inductance is introduced into the VSG and a virtual self-inductive magnetic chain is utilized to block the change of the transient fault current. This helps the inverter adjust the output voltage quickly. In addition, under the premise of meeting the reactive power margin, the reactive power compensation strategy is optimized to achieve a quick response in terms of the reactive power compensation of grid faults, which is helpful for realizing the LVRT of a VSG. Finally, the feasibility and effectiveness of the proposed LVRT method are verified by thorough simulation results.
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Kai Shi,Peng Lu,Yuxin Sun,Peifeng Xu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8
In recent years, a series of studies concerning the oscillation of interconnected systems has shown that frequency coupling has important effects on the stability of the system. In this paper, a more accurate theoretical model considering the frequency coupling effects is adopted to derive the transmission process in vector control, phase lock loop, and proportional–resonant controller of the harmonic perturbation in the frequency domain. This model is used to further deepen the application of harmonic linearization modeling to impedance modeling. An integrated three-phase modular multilevel converter simulation model based on the PSCAD platform is built to verify the accuracy of the theoretical modeling through the frequency sweep method. The influence of related system parameters on sequence and coupling impedance is analyzed in detail. The generalized Nyquist criterion is used to study the importance of coupling impedance to the stability analysis of the system.
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Liu Yize,Qiu Guanzhen,Luo Yinzhou,Li Shanshan,Xu Yeqiu,Zhang Yuanzhuang,Hu Jiayuan,Li Peifeng,Pan Hai,Wang Yong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-
As the most prevalent bone tumor in children and adolescents, the pathogenesis and metastasis of osteosarcoma (OS) remain largely unclear. Here, we investigated the expression and function of a novel circular RNA (circRNA), circROCK1-E3/E4, which is back-spliced from exons 3 and 4 of Rho-associated coiled-coil containing protein kinase 1 (ROCK1) in OS. We found that circROCK1-E3/E4, regulated by the well-known RNA-binding protein quaking (QKI), was downregulated in OS and correlated with unfavorable clinical features of patients with OS. Functional proliferation and cell motility assays indicated that circROCK1-E3/E4 serves as a tumor suppressor in OS cells. Mechanistically, circROCK1-E3/E4 suppressed proliferation and migration by upregulating phosphatase and tensin homolog (PTEN) through microRNA-532-5p (miR-532-5p) sponging. In the constructed nude mouse model, circROCK1-E3/E4 inhibited tumor growth and lung metastasis in vivo. This study demonstrates the functions and molecular mechanisms of circROCK1-E3/E4 in the progression of OS. These findings may identify novel targets for the molecular therapy of OS.
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