http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Step-Up Asymmetrical Nine Phase Delta-Connected Transformer for HVDC Transmission
Ammar, Arafet Ben,Ammar, Faouzi Ben The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
In order to provide a source for nine phases suitable for 18-pulse ac to dc power, this paper proposes a new structure for a step-up asymmetrical delta-connected transformer for converting three-phase ac power to nine-phase ac power. The design allows for symmetry between the nine output voltages to improve the power quality of the supply current and to minimize the THD. The results show that this new structure proves the equality between the output voltages with $40^{\circ}-{\alpha}$ and $40^{\circ}+{\alpha}$ phase shifting and produces symmetrical output currents. This result in the elimination of harmonics in the network current and provides a simulated THD that is equal to 5.12 %. An experimental prototype of the step-up asymmetrical delta-autotransformer is developed in the laboratory and the obtained results give a network current with a THD that is equal to 5.35%. Furthermore, a finite element analysis with a 3D magnetic field model is made based on the dimensions of the 4kVA, 400 V laboratory prototype three-phase with three-limb delta-autotransformer with a six-stacked-core in each limb. The magnetic distribution flux, field intensity and magnetic energy are carried out under open-circuit operation or load-loss.
Step-Up Asymmetrical Nine Phase Delta-Connected Transformer for HVDC Transmission
Arafet Ben Ammar,Faouzi Ben Ammar 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
In order to provide a source for nine phases suitable for 18-pulse ac to dc power, this paper proposes a new structure for a step-up asymmetrical delta-connected transformer for converting three-phase ac power to nine-phase ac power. The design allows for symmetry between the nine output voltages to improve the power quality of the supply current and to minimize the THD. The results show that this new structure proves the equality between the output voltages with 40°- α and 40°+ α phase shifting and produces symmetrical output currents. This result in the elimination of harmonics in the network current and provides a simulated THD that is equal to 5.12 %. An experimental prototype of the step-up asymmetrical delta-autotransformer is developed in the laboratory and the obtained results give a network current with a THD that is equal to 5.35%. Furthermore, a finite element analysis with a 3D magnetic field model is made based on the dimensions of the 4kVA, 400 V laboratory prototype three-phase with three-limb delta-autotransformer with a six-stacked-core in each limb. The magnetic distribution flux, field intensity and magnetic energy are carried out under open-circuit operation or load-loss.
SHECHTER SPECTRA AND RELATIVELY DEMICOMPACT LINEAR RELATIONS
Ammar, Aymen,Fakhfakh, Slim,Jeribi, Aref Korean Mathematical Society 2020 대한수학회논문집 Vol.35 No.2
In this paper, we denote by L the block matrix linear relation, acting on the Banach space X ⊕ Y, of the form ${\mathcal{L}}=\(\array{A&B\\C&D}\)$, where A, B, C and D are four linear relations with dense domains. We first try to determine the conditions under which a block matrix linear relation becomes a demicompact block matrix linear relation (see Theorems 4.1 and 4.2). Second we study Shechter spectra using demicompact linear relations and relatively demicompact linear relations (see Theorem 5.1).
TOPOLOGICAL PROPERTIES OF GRAPHENE USING ψk- POLYNOMIAL
AMMAR ALSINAI,ANWAR ALWARDI,N.D.SONER 장전수학회 2021 Proceedings of the Jangjeon mathematical society Vol.24 No.3
Graphene is a two-dimensional material consisting of a single layer of carbon atom arranged in a honeycomb structure. Graphine exhibits important intrinsic properties such as high strength, excellent conductor of heat and electricity. In this research, k-polynomial, when k = 2 for the line graph of Graphene is established, the degree-based topological indices, such as first, second and third leap Zagreb indices are obtained. Accordingly, by using the derivative of 2- polynomial of Graphene the first, second leap hyper-Zagreb indices, and leap forgotten topological index of Graphene, are found.
A CONVERGENCE RESULTS FOR ANTIPLANE CONTACT PROBLEM WITH TOTAL SLIP RATE DEPENDENT FRICTION
AMMAR, DERBAZI The Korean Society for Computational and Applied M 2021 Journal of applied mathematics & informatics Vol.39 No.5
In this work, we present the classical formulation for the antiplane problem of a eletro-viscoelastic materialswith total sliprate dependent friction and write the corresponding variational formulation. In the second step, we prove that the solution converges to the solution of the corresponding electro-elastic problem as the viscosity converges to zero.