Results 21 to 30 of about 6,020,339 (245)

Nucleus Drop or Intraocular Lens Drop Underwent Pars Plana Vitrectomy due to Complication of Cataract Surgery

IJRETINA (International Journal of Retina), 2019
Background: The incidence of nucleus drop or intraocular lens (IOL) drop as the complication of phacoemulsification increases due to the increased frequency of phacoemulsification.
Noviana Kurniasari Vivin, Ari Djatikusumo, Elvioza Elvioza, Gitalisa Andayani, Anggun Rama Yudantha, Mario Marbungaran Hutapea, Andi Arus Victor   +6 more
doaj   +1 more source

Stability Enhancement and Direct Speed Control of DFIG Inertia Emulation Control Strategy

IEEE Access, 2019
With the increasing penetration of renewable energy generators in power grid, traditional vector control (VC) strategy for double fed induction generator (DFIG) is unable to provide extra active power support to grid because DFIG inertia is made ...
Haoshu Shao, Xu Cai, Zheng Li, Dangsheng Zhou, Sujuan Sun, Liang Guo, Yunfeng Cao, Fangquan Rao   +7 more
doaj   +1 more source

Effect of Lower Limb vs. Abdominal Compression on Mobility in Orthostatic Hypotension: A Single-Blinded, Randomized, Controlled, Cross-Over Pilot Study in Parkinson’s Disease

Journal of Parkinson’s Disease, 2022
Background: Orthostatic hypotension (OH) in Parkinson’s disease (PD) is frequent and associated with impairments in quality of life and reduced activities of daily living.
Steffen Paschen, Clint Hansen, Julius Welzel, Judith Albrecht, Arash Atrsaei, Kamiar Aminian, Kirsten E. Zeuner, Robbin Romijnders, Elke Warmerdam, Paul Peter Urban, Daniela Berg, Walter Maetzler   +11 more
doaj   +1 more source

Dynamic power-based temporary frequency support scheme for a wind farm

Frontiers in Energy Research, 2022
Doubly fed induction generators can participate in frequency support following a disturbance by releasing their rotational energies. However, when regaining the rotor speed, a secondary frequency dip (SFD) tends to produce a sudden output drop.
Jiahan You, Dan Xu, Jiangdong Cao
doaj   +1 more source

Fast Frequency Control Strategy for Direct Drive Wind Turbines Considering the Suppression of Secondary Frequency Drop in the Power Grid

Journal of Physics: Conference Series, 2023
Abstract Inertia and damping in the power system are important parameters in frequency regulation and oscillation suppression. Inertia will reduce the rate and amplitude of frequency changes after active power sudden changes. Damping in the system can effectively suppress low-frequency oscillations after grid disturbances.
openaire   +1 more source

OTDM add-drop multiplexer based on time-frequency signal processing

, 2006
A time-division add-drop multiplexer capable of high-extinction-ratio operation is presented both theoretically and experimentally. The approach used is based on time-to-frequency domain conversion of optical signals and relies upon the switching of ...
Ibsen, M., Petropoulos, P., Parmigiani, F., Almeida, P.J., Richardson, D.J.   +4 more
core   +1 more source

Two-stage frequency regulation for wind turbines with adaptive coefficients and optimized power trajectory

International Journal of Electrical Power & Energy Systems
Wind turbines support grid frequency by rotor decelerating and then accelerating, but the instant power imbalance caused by rotor speed recovery may lead to a secondary frequency drop.
Zhiting Zhou, Hui Li, Jie Zheng, Hongtao Tan, Xuewei Xiang, Ran Yao   +5 more
doaj   +1 more source

Study on Quantitative Evaluation Index of Power System Frequency Response Capability

Energies, 2022
Frequency stability is an important factor for the safety and stability of the power system operation. In a traditional power system, the operation stability is ensured by the inertia response, primary frequency modulation, and secondary frequency ...
Cheng Chi, Hai Zhao, Jiahang Han
doaj   +1 more source

Equivalent Modeling and Comprehensive Evaluation of Inertia Emulation Control Strategy for DFIG Wind Turbine Generator

IEEE Access, 2019
With the increasing penetration of renewable energy in power grid, many inertia emulation control strategies have been proposed to provide extra support to the power grid in system disturbances. To explain the physical resemblance and relations among all
Haoshu Shao, Xu Cai, Dangsheng Zhou, Zheng Li, Dapeng Zheng, Yunfeng Cao, Yan Wang, Fangquan Rao   +7 more
doaj   +1 more source

Frequency Regulation Control Method for Wind Turbine and Energy Storage Equipment Considering Battery Energy Storage Exit Process

Shanghai Jiaotong Daxue xuebao
The integration of battery energy storage can prevent secondary frequency drop during wind power frequency regulation, thereby improving the frequency regulation capability of wind turbines.
XU Bo, SHANG Yunxiang, LIU Di, HUANG Zhiguang, LI Dongdong
doaj   +1 more source