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Dynamic analysis and fractional-order adaptive sliding mode control for a novel fractional-order ferroresonance system 下载免费PDF全文
Ferroresonance is a complex nonlinear electrotechnical phenomenon, which can result in thermal and electrical stresses on the electric power system equipments due to the over voltages and over currents it generates. The prediction or determination of ferroresonance depends mainly on the accuracy of the model used. Fractional-order models are more accurate than the integer-order models. In this paper, a fractional-order ferroresonance model is proposed. The influence of the order on the dynamic behaviors of this fractional-order system under different parameters n and F is investigated.Compared with the integral-order ferroresonance system, small change of the order not only affects the dynamic behavior of the system, but also significantly affects the harmonic components of the system. Then the fractional-order ferroresonance system is implemented by nonlinear circuit emulator. Finally, a fractional-order adaptive sliding mode control(FASMC)method is used to eliminate the abnormal operation state of power system. Since the introduction of the fractional-order sliding mode surface and the adaptive factor, the robustness and disturbance rejection of the controlled system are enhanced. Numerical simulation results demonstrate that the proposed FASMC controller works well for suppression of ferroresonance over voltage. 相似文献
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Jelena Đorović Zoran Marković Zorica D. Petrović Dušica Simijonović Vladimir P. Petrović 《Molecular physics》2017,115(19):2460-2468
The time-dependent density functional theory (TDDFT) was applied in conjunction with the natural bond orbital analysis to examine the UV-Vis properties of 10 phenolic Schiff bases. The calculations were performed with different functionals, but main discussion refers to results obtained at the B3LYP/6-311+G(d,p) level of theory. The approach based on the natural localised molecular orbital clusters indicates similar behaviour for majority of examined compounds. The HOMO (“highest occupied molecular orbital”) cluster is delocalised over the ring which is electron richer, the HOMO-1 cluster is spread over the other ring, whereas the LUMO (“lowest unoccupied molecular orbital”) cluster is situated on the imino group. The two bands at long wavelengths correspond to the HOMO → LUMO and HOMO-1 → LUMO transitions, i.e. from both A and B rings to the imino group. The next band originates from a transition from the imino group to the imino group. The band at the smallest wavelengths originates from a transition from the A ring to the A ring, or from the B ring to the B ring. Our findings are in very good agreement with the existing literature data. 相似文献
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Using the thin target — thin catchers techniques, masses, mean recoil energies and angular distributions of target residues have been measured for 86 MeV/nucleon12C induced reactions. Several different nuclear reaction processes, from peripheral to central collisions have been observed. Experimental results are partly reproduced by intranuclear cascade+evaporation calculations. Up to now, the production of the lightest masses (44<A<71) recoiling with high kinetic energies is not correctly understood by theoretical models. More exclusive experiments are needful to check if the formation of a highly excited quasi-compound nucleus could be a possible explanation of the phenomena. 相似文献
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Movement dynamics analysis for an optical pickup head lens actuator in a digital versatile disc system 总被引:1,自引:0,他引:1 下载免费PDF全文
With the rapid development of CD/DVD(compact disc/digital versatile disc)technology,the disc rotation speed and the information density have increased greatly to fulfil the demand of high informatiopn bit rate transfer,As one of the most important elements in a DVD pickup head,objective lens actuators are required to provide a more precise means to accurately follow the disc deviation.The design of the lens actuator becomes all the more important and critical.In order to give complete suggestion to the design of the lens actuator,we put forward the movement differnetial equations as a new theoretical means to analyse the characteristics of the lens actuator reliably and rigorously.Based on the theoretical analyses,many important and effective methods are propsed.A typical experiment verifies that the performance of our lens actuator head,which adopts these methods,can satisfy the high speed and high density requirement of DVD systems. 相似文献
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E. N. Perevoznikov 《Russian Physics Journal》2006,49(10):1076-1083
Two techniques for practical analysis of non-equilibrium system stability, which were demonstrated using an example of dynamics
of a charged subsystem in an electrical field, are presented. Analytical formulas of possible instabilities determining their
well-known and unknown mechanisms are derived.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 34–39, October, 2006. 相似文献
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The coupled vibration modes of a rotating blade-disc system are calculated by a finite element method. It is assumed that a large number of identical blades are present, such that the resulting blade loadings on the disc can be considered continuously distributed around the rim of the disc. The disc may have arbitrary profile, and the blades may be tapered and twisted, thus closely representing practical axial flow turbomachine configurations. The effects of rotation, thermal stress, and transverse shear and rotatory inertia in discs of moderately thick profile are readily incorporated into the finite element model. Calculated values of frequencies are compared with experimental data obtained on non-rotating models, and the convergence of the solution is examined by comparison with exact solutions, which can be obtained for configurations of simple geometry. Excellent agreement with experimental data is obtained when using remarkably few elements in the mathematical model, and convergence of the solution is extremely rapid. 相似文献
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Mustafa Inc Abdullahi Yusuf Aliyu Isa Aliyu Dumitru Baleanu 《Optical and Quantum Electronics》2018,50(4):190
This research presents soliton solutions and stability analysis to some conformable nonlinear partial differential equations (CNPDEs). The CNPDEs equations in this paper are conformable Cahn–Allen and conformable Zoomeron equations. The powerful sine-Gordon method is used to carry out the soliton solutions for these equations. The aspects of stability analysis for the considered equations is investigated using the linear stability technique. The sine-Gordon method proves to be efficient and effective for the extraction of soliton solutions for different types of CNPDEs. 相似文献
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2H-NbSe2 single crystal flake (ca. 2 × 2 × 0.5 mm in size) by chemical vapor transport is employed as the precursor for a top-down preparation of NbSe2 micro/nanoparticles by two kinds of processes, i.e. (1) mechanical exfoliation; (2) ultrasonic-assisted exfoliation in ethanol without ageing and with ageing for 210 days. NbSe2 micro/nanoparticles are applied on top of a Cu disk by a drop-casting process and the tribological property in sliding against a Cu pin under sliding electrical contact is investigated at room temperature. Mechanical exfoliation produces NbSe2 microplatets with typical sizes of 1 μm to 30 μ m with a thickness less than 2 μm. Ultrasonic-assisted exfoliation without aging facilitates the formation of NbSe2 micro/nanoplatets with sizes of 0.1 μm to 25 μm and nano-whiskers with 100 nm in diameter and 1 ~ 3 μm in length, but Nb2O5 and Se are also found on the basis of XPS results. Prolonged aging of the suspensions modifies the morphology by converting platets and whiskers into corrugated floccules (hybrid material), which are composed of Nb2O5, Se, NbSe2, and graphene. Notably, NbSe2 micro/nanoparticles by ultrasonic-assisted exfoliation without ageing exhibit an excellent lubricating property with low friction coefficient (0.3), mild wear, and longer wear lifetime (120 min) than that of mechanical exfoliated NbSe2 microplatets (10 min). The wear lifetime for the aged NbSe2 micro/nanoparticles can be as long as 504 min and are 4.2 times of the sample without aging, which can be a good solid lubricant for sliding electrical contact 相似文献
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The equilibrium structure of a three-phase contact line with negative line tension using a mean-field free-energy functional is calculated in the square-gradient approximation. The equilibrium density profiles are found by solving the Euler—Lagrange equations on a square grid of N 2 points covering an area of L 2. The fluctuations about the equilibrium structure are analysed via the spectrum of the free energy's second functional derivative. The equilibrium configuration is found to be stable with respect to fluctuations in the structure of the three-phase line and of the interfaces that meet at this line. In addition, the behaviour is investigated numerically of the lowest eigenvalue as the area of the grid is increased. The lowest eigenvalue is always positive and vanishes as 1/L 2. 相似文献
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We consider stability of periodic travelling waves in the generalized reduced Ostrovsky equation with respect to co-periodic perturbations. Compared to the recent literature, we give a simple argument that proves spectral stability of all smooth periodic travelling waves independent of the nonlinearity power. The argument is based on the energy convexity and does not use coordinate transformations of the reduced Ostrovsky equations to the semi-linear equations of the Klein–Gordon type. 相似文献
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We describe a class of self-dual dark nonlinear dynamical systems a priori allowing their quasi-linearization, whose integrability can be effectively studied by means of a geometrically based gradient-holonomic approach. A special case of the self-dual dynamical system, parametrically dependent on a functional variable is considered, and the related integrability condition is formulated. Using this integrability scheme, we study a new self-dual, dark nonlinear dynamical system on a smooth functional manifold, which models the interaction of atmospheric magneto-sonic Alfvén plasma waves. We prove that this dynamical system possesses a Lax representation that allows its full direct linearization and compatible Poisson structures. Moreover, for this self-dual nonlinear dynamical system we construct an infinite hierarchy of mutually commuting conservation laws and prove its complete integrability. 相似文献