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- 저자 : Haotian Wu (검색결과 6 건)
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Wu Cao,Kangli Liu,Sheng Xu,Haotian Kang,Jianfeng Zhao 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3
The frequent starting of large capacity lifting machines and other surge ship electrical loads will result in severe impacts on a shipboard power network, such as voltage and frequency fl uctuations. Therefore, a novel stabilization control strategy for shore power systems based on virtual synchronous generator is proposed in this paper, so as to improve the power quality and enhance the stability and reliability of shipboard power networks. In this strategy, a reactive power inertia component is embedded into the virtual synchronous generator aiming at shipboard surge reactive powers. On this basis, a voltage and frequency stability control method is presented to improve the static performances of shore power systems. In addition, a d-q decoupling control scheme in synchronous reference frame for the voltage and current double closed-loop control system is designed, and moreover, the infl uence of diff erent feedback voltages on the output characteristics of shore power supplies is studied. The theoretical analysis, simulation and experiment results show that, the proposed control strategy can eff ectively attenuate the frequency and voltage fl uctuations, eliminate the frequency and voltage steady-state errors, as well as realize the power distribution evenly for modular shore power supplies.
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Improved Switching Ripple Suppression Strategy for Multi-Paralleled Grid-Connected Inverters System
Wu Cao,Haotian Kang,Kangli Liu,Shunyu Wang,Jianfeng Zhao,Xiaochun Ji,Jun Zhao 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
The switching operations of inverters in the distributed system inevitably introduce high-frequency harmonics into grid, which may make influences on electrical devices. To address it, this paper proposes a ripple suppression strategy based on active cancellation combined with passive filtering. The active cancellation is realized by carrier-phase-shift (CPS) technique and the passive filtering is achieved by filters. Furthermore, two component-shared LCL-type filters improved by traditional LCL filters are studied from the points of resonance and accuracy of gridinjected current. To valid the effectiveness of the proposed strategy, simulations and experimental test are carried out. The results show that the proposed strategy can effectively suppress high-frequency harmonics and two componentshared LCL-type filters can become promising filters for the multi-paralleled grid-connected inverters.
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Design of Onboard Emulational Power Supply Exciter based on Virtual Instrument
Feng Tian,Haotian Wu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6
In the validation process of power supply subsystem of aviation electro-mechanical system, connecting the power supply equipment directly can lead to accidents caused by current overload or voltage overload. In order to prevent such accidents, this paper designed a kind of emulational power supply subsystem exciter based on virtual instrument technology. The design scheme uses AC and DC programmable power supplies and PXI series analog output devices which produced by National Instrument as power sources and analog signal sources representing lubricating oil temperature, oil surplus and so on. It uses PXI data acquisition devices as signal collectors. It accomplishes the data transmission between the hardware system and the principal computer software programmed by LabVIEW through PXI-8375 optical fiber communication interface devices. The software achieves functions of the real-time acquisition and the display of signals such as the power supply, the oil temperature, the oil surplus, the alarm and so on. The test shows that the system has good stability, high reliability in data transmission and strong versatility. This system has realized functions of data collection, storage and playback of the power supply, alarm signals and so on.
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Cheng Zhiping,Wang Kaifang,Li Zhongwen,Wu Haotian,Zhi Changyi,Zhang Jinbin 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
In this paper, distributed secondary control of AC microgrid (MG) is studied and the infuence of communication delay on its control performance is analyzed and verifed. Firstly, a secondary control strategy for the MG is designed to achieve frequency recovery and proportional active power dispatch. Secondly, the stability of the MG system is analyzed in the frequency domain and a rigorous formula is derived to calculate the delay margin for the stability of the distributed secondary control with communication delays. The theoretical calculation results of the stability margin are approximately consistent with the simulation results, with an error of only 1.27%. The efects of the algorithm gains, communication topology, and connection weights on the delay margin are discussed based on the derived formula. The results demonstrate that the algorithm gain is inversely proportional to the delay margin. Changes in the communication topology and connection weights lead to changes in the maximum eigenvalue of the adjacency matrix L, which in turn afects the delay margin. Moreover, the infuence of time-varying delays is considered. The system can tolerate greater time-varying delays than fxed delays. Simulation and experimental results validate the efectiveness and feasibility of the proposed method.
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Jiguang Hou,Dong Ren,Yufeng Chen,Lindan Geng,Shuangquan Yao,Haotian Wu,Pengcheng Wang 대한척추신경외과학회 2023 Neurospine Vol.20 No.1
Objective: This study aimed to examine the effect of the endplate reduction (EPR) technique combined with bone grafting for treating thoracolumbar burst fractures using posterior shortsegmental fixation. Methods: Patients with thoracolumbar fractures admitted between January 2018 and October 2021 were retrospectively analyzed, and those meeting the criteria were assigned to the EPR group and the intermediate screws (IS) group. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), upper endplate line (UEPL), upper intervertebral angle (UIVA), and upper intervertebral disc height (UIDH) indices were examined and compared preoperatively, first day postoperatively, as well as at 12 months postoperatively. Results: The result indicated that the EPR group achieved better MVBH reduction (p < 0.001), UEPL reduction (p < 0.001), vertebral body fracture healing (p = 0.006), as well as implant breakage (p = 0.04) than the IS group; VWA (p < 0.001), CA (p = 0.005), AVBH (p < 0.001), MVBH (p < 0.001), UEPL (p < 0.001), and UIDH (p < 0.001) were lost after reduction less than those in the IS group. There was no significant difference in operative time (p = 0.315) and intraoperative bleeding (p = 0.274) between the 2 groups. Conclusion: The EPR group achieved better results in repositioning and maintaining MVBH and endplate morphology, with less correction loss after the reduction of the VWA, CA, AVBH, and endplate morphology. The EPR group exhibited a better healing pattern after vertebral fracture and disc degeneration was better relieved.
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