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Maximum power point tracking (MPPT) is required to extract the maximum available power in PV systems. Wide variety of methods exist in literature, with range of complexity and effectiveness. The features of these diverse methods are usually evaluated at specific environmental conditions for a tiny period, and then the evaluations are generalized for PV systems working under long-term environmental...
The transient interruption characteristics and reignition conditions of direct-current (DC) forced current zero for vacuum interrupters in 270 V power-supply systems are discussed. Three stages are identified in forced interruption: DC arcing stage, current commutation stage, and voltage recovery stage. During the current commutation stage, the reverse peak current coefficient k, which is a key design...
In wireless communication systems oscillators are basic components in the transmitter and receiver unit. However, the design process of an oscillator is very challenging. At first, an appropriate topology has to be selected and then the circuit has to be dimensioned. For this purpose, a high dimensional design space has to be considered in order to meet given specifications. Usually this design step...
A system and source joint estimation method for EM emission modeling is proposed in this paper. Based on the priori knowledge, i.e., the transfer function of system is smooth and the form of source signal was already known, the paper using joint estimation method to solve modeling problems when measured only the emission amplitude spectra at some ports. Experimental results verify the method could...
This paper exploits Duffing equation and discusses some numerical methods to solve it. Numerical calculation's errors of the amplitude and the period of free oscillations of a large time interval of codes TR, BDF, and RADAU5 are computed. Publications describe a plurality of stiff test problems. The highly oscillating problems is known much less. Duffing equation can serve as test concurrently stiff...
This paper presents two approaches to model the startup behavior of cross-coupled oscillators for regenerative sampling applications. The first approach closely models the building blocks and connections of the circuit at the device level, whereas the second approach uses an equivalent model based on the analysis of the differential currents in the circuit to simplify the calculation and obtain a...
In this study, synchronization observed in dynamical oscillatory networks with non-uniform coupling distributions is investigated. The coupling states (on/off) of all connections are stochastically determined at every certain time with the coupling probability. We focus on the heavy tail type of coupling distribution for the network. By using computer simulations, we confirm that the dynamical network...
The paper considers a new electric diagram of the microelectronic self-excited oscillator based on the bipolar transistor structure with negative resistance. The oscillator operates in oscillatory and relaxation modes. Chaotic mode of the self-excited oscillator was provided by installing additional components into a basic circuit. Results of the deterministic chaos microelectronic oscillator simulation...
Dynamical model of electrocardiogram, cardiovascular and seismocardiographic system are important in medicine because they can be used as an approximation of the real patient. Synthetic cardio-signals can be generated with different shapes, different sampling frequencies, and different noise levels to establish the performance of the used technique. In this paper, the cardio-signals were modeled,...
Non-hyperbolic points of slow-fast systems (also known as singularly perturbed ordinary differential equations) are responsible for many interesting behavior such as relaxation oscillations, canards, mixed-mode oscillations, etc. Recently, the authors have proposed a control strategy to stabilize non-hyperbolic points of planar slow-fast systems. Such strategy is based on geometric desingularization,...
The track of the maximum power point (MPPT) is an important part of photovoltaic systems. Incremental conductance method is considered to be the most commonly used method because it is less complicated and has good tracking accuracy.
in this paper, an integral sliding mode control method is proposed for maximum power point tracking MPPT voltage oriented loop. The aim is to obtain a better performance when applying it to stand alone. The proposed technique is studied and simulated by using Matlab/Simulink and simpower system packages. The obtained simulation results display significant enhancements by applying the proposed method...
Spin torque oscillators (STO) have drawn significant attention from the research community as potential replacements for electrical oscillators due to their simple and compact structure.
To extend the concept of the memristive systems to capacitive systems, memcapacitive systems have been described in 2009. Memcapacitors which are a subset of memcapacitive systems are flux-dependent nonlinear circuit elements with memory. Materials with memcapacitive properties has already been reported in literature. The elusive memcapacitor show promise for new type of applications because of their...
This paper addresses mainly to the analysis of the emerging memristor-based oscillators. This novel oscillator, unable to be expressed in the form of the feedback system, cannot be analyzed using the conventional Barkhausen criterion. Here we propose an oscillation condition analysis method based on Hopf bifurcation theory, in which we introduce the first Lyapunov coefficient to determine whether...
In recent years, applications of ultracapacitor in electrical systems have witnessed a rise due to their high power density. Ultracapacitors are known to possess inherent nonlinear dynamics with long term memory, which can be better, described using fractional calculus. This article addresses possible application of ultracapacitors for the design of very low frequency (VLF) oscillators. The presence...
In the paper a deterministic chaos oscillator based on a bipolar and field-effect transistor structure with negative resistance is proposed and examined. A modified mathematical model of Anishchenko-Astakhov is proposed for describing the chaotic oscillation dynamics. The results of mathematical modelling and experimental research are obtained.
In this study, we investigate synchronization in complex network with two hubs by using parametrically excited van der Pol oscillators with parameter mismatch. By means of computer simulation, we confirm various change of synchronization probability in complex network, and observe effects on synchronization probability by changing structural metrics (degree and path length) in subset of the nodes...
This paper presents an original approach to estimate the accuracy of numerical algorithms of transient analysis for four test problems. The tests are presented as mathematical models and electronic circuits too. Test problems and methods of estimation of numerical analysis algorithms' accuracy proposed in the present paper can be used in circuit simulators and in computer mathematics programs to test...
This paper explains a procedure on how to select resonant circuit components of a unique direct three-phase to single-phase AC/AC converter for a contactless electric vehicle (EV) charger. The topology has a fewer bi-directional switches than a matrix converter and consists of a resonant circuit to utilize a zero-current switching (ZCS) mechanism. The selection goal was to realize a working prototype...
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