Results 21 to 30 of about 306,242 (273)

Spherical Orbifolds for Cosmic Topology [PDF]

, 2012
Harmonic analysis is a tool to infer cosmic topology from the measured astrophysical cosmic microwave background CMB radiation. For overall positive curvature, Platonic spherical manifolds are candidates for this analysis.
Aurich R, Coxeter H S M, Edmonds A R, Einstein A, Kramer P, Kramer P, Kramer P, Kramer P, Kramer P, Kramer P, Kramer P, Kramer P, Larson D, Laue M v, Lax M, Misner Ch W, Peter Kramer, Ratcliffe J G, Seifert H, Sommerville D M Y, Weeks J, Wolf J A   +21 more
core   +1 more source

Solution technology of system side harmonic variable impedance based on minimum norm

电力工程技术, 2023
To calculate the harmonic impedance on the system side is crucial for the safe and stable operation of the new power system. Existing algorithms for harmonic impedance estimation usually assume that the harmonic impedance on the system side is constant ...
XU Fangwei, ZENG Xue, WANG Chuan, ZHENG Hongru   +3 more
doaj   +1 more source

On the D = 4, N = 2 Non-Renormalization Theorem [PDF]

, 1997
Using the harmonic superspace background field formulation for general D=4, N=2 super Yang-Mills theories, with matter hypermultiplets in arbitrary representations of the gauge group, we present the first rigorous proof of the N=2 non-renormalization ...
Buchbinder, Buchbinder, Buchbinder, Burt A. Ovrut, Dine, Dragon, Galperin, Galperin, Grisaru, Henningson, Howe, Howe, Ioseph L. Buchbinder, Ivanov, Seiberg, Sergei M. Kuzenko, Siegel, Zupnik, Zupnik   +18 more
core   +2 more sources

Assessment on Harmonic Emission Level of Residential Loads with Symmetry and Volatility Constraints

Zhongguo dianli, 2020
The accuracy of harmonic emission level assessment of residential loads is affected by background harmonics or three-phase harmonic unbalance. Based on Norton’s and Davinan’s theorem, a model is constructed for assessment of harmonic emission level.
Huaying ZHANG, Mingxing ZHU, Hengtong SHI, Qing WANG, Hongxin LI, Min GAO   +5 more
doaj   +1 more source

Novel Method for Estimating Utility Harmonic Impedance for a Direct-Drive Permanent Magnet Synchronous Generator Wind Farm

IEEE Access, 2022
Accurate estimation of the utility harmonic impedance is significant for harmonic control and responsibility division. Traditional methods of estimating the utility harmonic impedance are valid on the premise that the harmonic impedance on the wind-farm ...
Runze Zhou, Xiaoyang Ma, Rui Xu, Xianyong Xiao, Jinshuai Zhao   +4 more
doaj   +1 more source

Multi-Harmonic Sources Harmonic Contribution Determination Based on Data Filtering and Cluster Analysis

IEEE Access, 2019
Accurately determining power consumer harmonic contribution determination is an effective method to solve power quality disputes and alleviate harmonic pollution of power grids.
Haoyuan Sha, Fei Mei, Chenyu Zhang, Yi Pan, Jianyong Zheng, Taoran Li   +5 more
doaj   +1 more source

Evaluation of Harmonic Contributions for Multi Harmonic Sources System Based on Mixed Entropy Screening and an Improved Independent Component Analysis Method

Entropy, 2020
Evaluating the harmonic contributions of each nonlinear customer is important for harmonic mitigation in a power system with diverse and complex harmonic sources.
Jinshuai Zhao, Honggeng Yang, Xiaoyang Ma, Fangwei Xu   +3 more
doaj   +1 more source

Inverter harmonic perturbations rejection in renewable energy conversion systems applying a super‐twisting algorithm

IET Renewable Power Generation, 2021
Grid background and dead‐time harmonic perturbations pose challenges in maintaining power quality and stability in the grid integration of renewable energy conversion systems.
Daniel Memije, Oscar Carranza, Jaime J. Rodríguez, Rubén Ortega, Edgar Peralta   +4 more
doaj   +1 more source

DETECTION OF A HARMONIC SIGNAL AGAINST THE BACKGROUND OF A NONSTATIONARY GAUSSIANINTERFERENCE WITH COMPLEX SPECTRUM

Information and Telecommunication Sciences, 2021
Background. Modern radar stations for various purposes operate in the conditions of interference created by the imprints of the radar signal from the background surface, from metrological formations (precipitation, clouds, etc.) and artificial radiation ...
Ігор Прокопенко, Ігор Омельчук, Анастасія Дмитрук, Юлія Петрова   +3 more
doaj   +1 more source

An Adaptive Virtual Impedance Method for Grid-Connected Current Quality Improvement of a Single-Phase Virtual Synchronous Generator under Distorted Grid Voltage

Sensors, 2023
The proportion of distributed generation systems in power grids is increasing, leading to the gradual emergence of weak grid characteristics. Moreover, using voltage-sourced grid-connected inverters can enhance the stability of a weak grid.
Caomao Zhong, Zhi Zhang, Anan Zhu, Benxin Liang   +3 more
doaj   +1 more source