Search

This paper proposes a design and implementation of an axial type magnetic gear (MG) based on the composition of the magnetic arrangement. We report a quantitative comparison of two MG topologies with rectangular magnets arranged in series and parallel. Increased magnetic flux is done through magnetic circuit analysis and electrical circuit approach. Testing is done by using the rotation of a DC motor drive from 300–2600 rpm with a DC generator under load conditions. Measurement of load current and generator output power for both axial MG topologies are taken and analyzed. The results showed that the performance of an axial MG with the rectangular magnetic arrangement in parallel is better than that of a series arrangement. Based on the measured loading current of the two axial MG topologies, at generator rotation between 300–1300 rpm with 100, 200, and 300 Ω resistance loads show the same load current. Conversely, after a DC generator rotation approaches ½ of the maximum rotation (1300–2600 rpm) there is a significant increase in load current fluctuations. That is, with an increase of load currents occurring, the parallel magnetic topology shows an increase in load torque due to an increase of magnetic flux in the gear train magnets of the MG.

Nowadays , most students are familiar with the notebook for daily use. The compactness and flexibility of the notebook offer more benefits than a PC. The teachers can engage it during teaching physics. Hence, th is research had developed an electrical circuit virtual experiment that acts like real experiments . It can be accessed easily by students in their notebook. This study introduces a flash-based animation C ircuit B uilder as a simulation designed to help students understand the electrical circuit. This study's purposes were: (1) to analyze the feasibility level of Circuit Builder for enhancing students’ electrical circuit mastery and (2) to know the effectiveness of Circuit Builder based on students’ electrical circuit mastery. Circuit Builder was developed by 4D (Define, Design, Develop, and Disseminate) model. The feasibility level was analyzed by CVI (Content Validity Index). Then, the effectiveness was tested with effect size . This study proved that the virtual laboratory "Circuit Builder” was feasible in physics class with a moderate effect size. The virtual laboratory could improve students’ electrical circuit mastery than doing practices with traditional laboratories .

The students need a learning strategy that is compatible to develop electrical circuit problems completion. Additionally, problem-solving strategy (epistemic game) will develop a learning process that can stimulate the completion of physics. This case encourages the researcher to determine the epistemic game of moderate physics-capable students in solving electrical circuit problems. Moreover, it is qualitative research, and the participant of the research is the students who learn the electrical circuit. Moderate physics-capable students (4 moderately capable students out of 13 students) based on their physics understanding test results. Test and interview were used by the researcher to collect data. The test consists of a physics understanding test and an electrical circuit test. The physics understanding test is used to determine the level of students’ physics understanding, while the electrical circuit test is used to determine students’ epistemic games to solve the problems. The research finding showed the epistemic game of moderate physics-capable students was obtained from the analysis result of the electrical circuit test and interview. The analysis result of the first test, the second test, the third test, and the seventh test showed that the game used to solve problems was transliteration to mathematics. Meanwhile, the students used mapping mathematics to meaning and transliteration to mathematics to solve the problems in the fourth test. The analysis result of the fifth test and the eight test showed that the students used mapping mathematics to meaning to solve the problems. Furthermore, the sixth test was completed by mapping meaning to mathematics.

Renewable Distributed Generation (RDG), when connected to a Distribution Network (DN), suffers from power quality issues because of the distorted currents drawn from the loads connected to the network over generation of active power injection at the Point of Common Coupling (PCC). This research paper presents the voltage rise regulation strategy at the PCC to enhance power quality and continuous operation of RDG, such as Photovoltaic Arrays (PVAs) connected to a DN. If the PCC voltage is not regulated, the penetration levels of the renewable energy integration to a DN will be limited or may be ultimately disconnected in the case of a voltage rise issue. The network is maintained in both unity power factor and voltage regulation mode, depending on the condition of the voltage fluctuation occurrences at the PCC. The research investigation shows that variation in the consumer’s loads (reduction) causes an increase in the power generated from the PVA, resulting in an increase in the grid current amplitude, reduction in the voltage of the feeder impedance and an increase in the phase voltage amplitude at the PCC. When the system is undergoing unity power factor mode, PCC voltage amplitude tends to rises with the loads. Its phase voltage amplitude rises above an acceptable range with no-loads which are not in agreement, as specified in the IEEE-1547 and Southern Africa grid code prerequisite. Incremental Conduction with Integral Regulator bases (IC + PI) are employed to access and regulate PVA generation, while the unwanted grid current distortions are attenuated from the network using an in-loop second order integral filtering circuit algorithm. Hence, the voltage rise at the PCC is mitigated through the generation of positive reactive power to the grid from the Distribution Static Compensator (DSTATCOM), thereby regulating the phase voltage. The simulation study is carried out in a MATLAB/Simulink environment for PVA performance.

For one-dimensional (1D) topological insulators, the edge states always reside in the bulk bandgaps as isolated modes. The emergence and vanishing of these topological edge states are always associated with the closing/reopening of the bulk bandgap and changes in topological invariants. In this work, we discover a special kind of edge state in a 1D electrical circuit, which can appear not only inside the bandgap but also outside the bulk bands with the changing of bulk circuit parameters, resembling Tamm states or Shockley states. We prove analytically that the emergence/vanishing of this edge state and its position relative to the bulk bands depends on the intersections of certain critical frequencies. Specifically, the edge mode in the proposed circuit can be mathematically described by polynomials with roots equal to some critical frequencies in the bulk circuit. From this point of view, the transition of the edge state is uniquely determined by the order of the critical frequencies in the bulk circuit. Such topological behaviors shown by the edge state in the proposed electrical circuit may indicate, in a broader sense, the presence of certain type of topology.

Our research into the formation of a functional copper-containing surface layer on parts of automobile engines by using an alignment tribotechnology has established a decrease in the wear of parts during their operation. It was found that the formed coating creates an elastic layer that reduces strains in a material of engine parts. Our experimental study of the coercive force of parts' working surfaces has confirmed a decrease in the accumulation of destructive stresses in the near-surface layers of a components' material. In turn, a comparative analysis of the obtained results by using a coercimetric method confirms that the proposed aligning tribotechnology leads to reduction of the stressed-strained state and makes it possible to improve wear resistance and enhance the technical condition of diesel engine cylinder liners: the magnitude of coercive force reduces by 7.5 %, while operating time increases by 16 %. In this case, at larger operating time: 254.8 thousand km against 220.5 thousand km, according to data on the coercive force (14.2…9.1) A/cm and (13.2…9.0) А/cm, it is almost in the same condition.The functional surface layer forms when introducing a composite oil to the tribotechnology of cold alignment of an automobile powertrain. We have proposed and implemented a circuit to connect electric current to components at an engine's cylinder-piston group as a result of studying the developed tribotechnology of alignment. The features of this scheme are that the constant electric current is supplied by the plus polarity, through the brush-collector node, to the crankshaft, and by the minus polarity, through the clamping contact, to the crankcase block.The research results suggest a possibility to control the internal strains and the subsequent magnitude of wear in a material of working heavily-loaded components of automobile powertrains provided they are serviced properly. The proposed tribotechnology of alignment could be of interest for both service departments at trucking companies and for car service stations., Проведеними дослідженнями формування функціонального мідьвмісного поверхневого шару на деталях двигунів автомобілів триботехнологією припрацювання встановлено зниження зношування деталей підчас їх експлуатації. Виявлено, що сформоване покриття створює можливість еластичного шару який зменшує напруження в матеріалі деталей двигунів. Експериментальними дослідженнями коерцитивної сили робочих поверхонь деталей підтверджено зниження накопичення руйнуючих напружень в приповерхневих шарах матеріалі деталей. В свою чергу, порівняльний аналіз отриманих результатів коерцитиметричним методом підтверджує, що запропонована триботехнологя припрацювання приводить до зменшення напружено-деформованого стану та дає можливість підвищити зносостійкість і поліпшити технічного стану гільз циліндрів дизеля: величина коерцитивної сили знижується на 7,5 %, в той час коли напрацювання збільшується на 16 %. При цьому при більшому напрацюванні: 254,8 тис. км проти 220,5 тис км за даними коерцитивної сили (14,2…9,1) А/см і (13,2…9,0) А/см знаходиться в практично однаковому технічному стані.Функціональний поверхневий шар формується при впроваджені композиційної оливи в триботехнологію холодного припрацювання силового агрегату автомобіля. Запропоновано та реалізовано схему підключення електричного струму до деталей циліндропоршневої групи двигуна при дослідженні розробленої триботехнології припрацювання. Особливості даної схеми є те, що постійний електричний струм подається наступною полярністю, плюсом, через щітково-колекторний вузол на колінчастий вал, а мінусом, через затискний контакт на блок картер.Результати досліджень дають підстави стверджувати про можливість контролю внутрішніх напружень та подальшої величини зношування в матеріалі робочих важконавантажених деталей силових агрегатів автомобілів підчас певних їх сервісних діях. Запропонована триботехнологія припрацювання може представляти інтерес як для сервісних служб автотранспортних підприємств, так і для станцій технічного обслуговування автомобілів, Проведенными исследованиями формирования функционального медьсодержащего поверхностного слоя на деталях двигателей автомобилей триботехнологією приработки установлено снижение изнашивания деталей при их эксплуатации. Выявлено, что сформированное покрытие создает возможность эластичного слоя, который уменьшает напряжения в материале деталей двигателей. Экспериментальными исследованиями коэрцитивной силы рабочих поверхностей деталей подтверждено снижение накопления разрушающих напряжений в приповерхностных слоях материала деталей. В свою очередь, сравнительный анализ полученных результатов коэрцитиметричним методом подтверждает, что предложенная триботехнологя её приработки приводит к уменьшению напряженно-деформированного состояния и дает возможность повысить износостойкость и улучшить техническое состояние гильз цилиндров дизеля: величина коэрцитивной силы снижается на 7,5 %, в то время когда наработки увеличивается на 16 %. При этом при большей наработке: 254,8 тыс. км против 220,5 тыс км по данным коэрцитивной силы (14,2...9,1) А/см и (13,2...9,0) А/см находится в практически одинаковом техническом состоянии.Функциональный поверхностный слой формируется при внедрении композиционного масла в триботехнологию холодной приработки силового агрегата автомобиля. Предложена и реализована схема подключения электрического тока к деталям цилиндро-поршневой группы двигателя при исследовании разработанной триботехнологии приработки. Особенностями данной схемы является то, что постоянный электрический ток подается в следующей полярностью, плюсом, через щеточно-коллекторный узел на коленчатый вал, а минусом, через зажимной контакт, на блок картер.Результаты исследований дают основания утверждать о возможности контроля внутренних напряжений и последующей величины износа в материале рабочих тяжелонагруженных деталей силовых агрегатов автомобилей при определенных их сервисных действиях. Предложенная триботехнологія приработки может представлять интерес, как для сервисных служб автотранспортных предприятий, так и для станций технического обслуживания автомобилей

The problem of voltage dynamics description in a circuit containing resistors, and at least two fractional order elements such as supercapacitors, supplied with constant voltage is addressed. A new operator called Conformable Derivative in the Caputo sense is used. A state solution is proposed. The considered operator is a generalization of three derivative definitions: classical definition (integer order), Caputo fractional definition and the so-called Conformable Derivative (CFD) definition. The proposed solution based on a two-parameter Conformable Derivative in the Caputo sense is proven to be better than the classical approach or the one-parameter fractional definition. Theoretical considerations are verified experimentally. The cumulated matching error function is given and it reveals that the proposed CFD–Caputo method generates an almost two times lower error compared to the classical method.

On the basis of the classical theory of robust control, the theory of stability and the theory of continued fractions, the linearized mathematical model, the procedure for calculating and designing an analog electrical circuit of the H∞-suboptimal robust controller of the flux-linkage control system of the rotor of an asynchronous electric drive, protected by Ukrainian Patent no.137157, were built. The circuit contains three operational amplifiers, several resistors and capacitors. The proposed mathematical model, the procedure for calculating and choosing the parameters of the resistors and capacitors of the circuit take into account the random variations of the object and the controller within the specified boundaries. An analytical relationship between the transfer function coefficients and the resistances of the resistors and the capacitances of the capacitors of the controller's electrical circuit was established. On a specific example, by calculation according to the developed algorithm, the limiting values of the tolerances of the circuit's resistances of the resistors and capacitances of the capacitors were identified and these values were selected with a margin from the standard series. Analysis of noise filtering by the electrical circuit of the controller in the Multisim package shows its insensitivity to noise spreads within fairly wide boundaries., На базі класичної теорії робастного управління, теорії стійкості і теорії ланцюгових дробів побудовано лінеаризована математична модель, процедура розрахунку і проектування аналогової електричної схеми Н∞-субоптимального робастного регулятора системи управління потокозчепленням ротора асинхронного електроприводу, що захищена патентом України № 137157. Схема містить три операційних підсилювача, кілька резисторів і конденсаторів. Запропонована математична модель, процедура розрахунку і вибору параметрів резисторів і конденсаторів схеми враховують випадкові варіації об’єкта і регулятора в заданих межах. Встановлено аналітичний зв’язок між коефіцієнтами передавальної функції і опорами резисторів і ємностями конденсаторів електричної схеми регулятора. На конкретному прикладі розрахунковим шляхом за розробленим алгоритмом виявлені граничні значення допусків опорів резисторів і ємностей конденсаторів схеми і здійснений їх вибір із запасом зі стандартних рядів. Аналіз фільтрації завад електричною схемою регулятора в пакеті Multisim показує її нечутливість до розмахів завад у досить широких межах.

Negative bias temperature instability (NBTI) is a phenomenon commonly observed in p-channel metal-oxide semiconductor (MOS) devices simultaneously exposed to elevated temperature and negative gate voltage. This paper studies threshold voltage shift under static stress associated with the NBT stress induced buildup of both interface traps and oxide trapped charge in the commercial p-channel power VDMOSFETs IRF9520, with the goal to design an electrical model. Experiments have done with the goal to obtain data for modeling. Change of threshold voltage follow power law t n , where parameter n is different depending on the stressing phase and stressing conditions. Two modeling circuits are proposed and modeling circuit elements values are analyzed. Values of modeling circuits elements are calculated using least square method approximation conducted on obtained experimental results. Modeling results of both circuits are compared with the measured results and then further discussed.

The problem of calculation of the characteristic equations of the standard and descriptor linear electrical circuits of integer and fractional orders is addressed. It is shown that the characteristic equations of standard and descriptor linear electrical circuits are independent of the method used in their analysis: the state space method, the mesh method and the node method. The considerations are illustrated by examples of standard and fractional linear electrical circuits.

The small parameter method, implemented in frequency domain, was used for the analytical analysis of nonlinear electrical circuits of electrotechnical systems. To have the possibility of calculations in frequency domain, the automated method of forming orthogonal harmonic components of electrical magnitudes based on the algorithm of discrete convolution was used. The characteristic of a nonlinear element was represented by the polynomial function of third degree. It was shown that application of the small parameter method with its realization in frequency domain makes it possible to simplify the process of analyzing electrical circuits with nonlinear elements by automating calculations in the mathematical package. Analytical and numerical calculations of a circuit with actively inductive load demonstrated sufficient accuracy of the proposed method, the relative error for the main harmonic of current did not exceed 6 %. The conducted comparative analysis of the proposed small parameter method with the classic small parameter method on the example of calculation of an electrical circuit with RL load showed that the developed method provides better adequacy of results and high calculation accuracy in comparison with the existing one. Relative error by amplitude of first and third harmonics of current does not exceed 2.5 %, and by phase, it does not exceed 1.042·10 -3 %. The method of numerical structural modeling was used to determine the reference values of current of the researched circuit. The results of the research can be used in calculations of electrotechnical devices, containing semiconductor components and electrical devices with nonlinear characteristics. In addition, the obtained results will make it possible to improve the processes of active compensation of harmonics of current in electrical networks with nonlinear load and to develop the tools of passive compensation

The assessment of the impact of per unit length parameter errors on the determination of wave parameters, currents, and voltages at the end of the line has been presented in the paper. The impact on the above-mentioned values has been indicated. This paper presents an assessment of the impact of per unit parameter errors on the determination of both wave parameters, as well as currents and voltages at the end of a transmission line, although it is mainly focused on indicating which of the per unit parameters have the strongest impact on the above-mentioned values. For this purpose, elements of incremental sensitivity have been used.

What hinders current models for fluid transportation in three-dimensional (3D) fracture system from considering fracture roughness is model complexity, which makes it hard to get convergent results. Therefore, we propose an electrical circuit (EC) model to simulate fracture flow, with each rough rock fracture taken as an EC with distributed electrical resistances, where the voltage and current are taken as the counterparts of pressure and flow rate, respectively. The robustness of EC model is validated against the computational fluid dynamics (CFD) simulations and laboratory experiments. Additionally, the EC model exhibits a very high computational efficiency (takes several seconds) compared with that of the CFD model (takes a couple of minutes). The proposed EC model is expected to have broader applications in fracture flow analysis as it applies not only to persistent fractures with tiny mechanical apertures but also to non-persistent fractures having substantial portions of contact areas. The authors thank the "Start-up Funding for New Faculty" provided by the Nanjing University of Aeronautics and Astronautics.

The specific duality and asymptotic stability of the positive linear electrical circuits are addressed. The specific duality of positive linear electrical circuits composed of resistances, inductances, capacitances and source voltages is established. 1) The linear electrical circuits are positive if and only if the common branches between meshes with resistances and inductances and meshes with resistances and capacitances contain only source voltages; 2) In linear electrical circuits the interchanges of the inductances by the capacitances and the capacitances by inductances do not change the asymptotic stability of the electrical circuits. The asymptotic stability of the positive and nonpositive electrical circuits is analyzed.

The photovoltaic (PV) generator current-voltage equation is nonlinear and need a powerful algorithm to solve it. In this paper a dynamic modelling approach of photovoltaic generator is presented by the bond graph (BD) methodology. The BD is a graphical methodology for modelling and analysis of physical systems. It’s based on decomposition of the system in subsystems and exchange energy. Therefore, using the single and double diode models representation of equivalent circuit of PV generator, the bond graph representation is derived. The mathematical model is obtained by applying the bond graph elements and rules. At the end, the simulation results of these obtained models using experimental points are plotted.

We consider nonlinear electrical circuits for which we derive a port-Hamiltonian formulation. After recalling a framework for nonlinear port-Hamiltonian systems, we model each circuit component as an individual port-Hamiltonian system. The overall circuit model is then derived by considering a port-Hamiltonian interconnection of the components. We further compare this modeling approach with standard formulations of nonlinear electrical circuits.

The problem of zeroing of the state variables in fractional descriptor electrical circuits by state-feedbacks is formulated and solved. Necessary and sufficient conditions for the existence of gain matrices such that the state variables of closed-loop systems are zero for time greater zero are established. The procedure of choice of the gain matrices is demonstrated on simple descriptor electrical circuits with regular pencils

We investigate the validity of the formal expansion method for solving a second order ordinary differential equation raised from an electrical circuit problem. The formal expansion method approximates the exact solution using a series of solutions. An approximate formal expansion solution is a truncated version of this series. In this paper, we confirm using simulations that the approximate formal expansion solution is valid for a specific interval of domain of the free variable. The accuracy of the formal expansion approximation is guaranteed on the time-scale 1.

This paper presents an approach to solve coupled systems where electrical/mechanical devices, whose behaviour is governed by a PDE or a system of PDEs, are connected together through an electrical circuit. In an earlier paper [1], it had been shown that PDEs can be modeled by an electrical equivalent circuit generated from the complete set of equations arising from the Finite Element Method (FEM). In this paper, the approach is extended to solve a system of PDEs. The approach allows the simulation of coupled systems with circuit simulation tools alone since the resultant system becomes an electrical circuit after an application of electrical analogy. The coupled system is solved by directly replacing PDE devices with the equivalent circuits. Further, a special circuit simulation technique, viz. multiport decomposition is used in order to solve a large coupled system. A sequential as well as a parallel simulator is built for coupled problems based on the proposed approach. A circuit with 100 linear PDE devices (the equivalent circuit contains 8 million nodes) has been simulated using the parallel simulator in less than 1 h. We have achieved a speedup of 5 over the sequential simulator using 8 processors on distributed memory architecture. The characteristic of p-n junction diode (drift-diffusion equation) is analyzed by our circuit simulator to show that the proposed approach can be used to build a circuit-cum-device simulator. (C) 2012 Elsevier B.V. All rights reserved.

Based on the traditional regenerative braking electrical circuit, a novel energy recovery system for the main and auxiliary sources of electric vehicles (EVs) has been developed to improve their energy efficiency. The electrical circuit topology is presented in detail. During regenerative braking, the recovered mechanical energy is stored in both the main source and the auxiliary source at the same time. The mathematical model of the proposed system is derived step by step. Combining the merits and defects of H 2 optimal control and H ∞ robust control, a H 2 /H ∞ controller is designed to guarantee both the system performance and robust stability. The perfect match between the simulated and experimental results validates the notion that the proposed novel energy recovery system is both feasible and effective, as more energy is recovered than that with the traditional energy recovery systems, in which recovered energy is stored only in the main source.

Augmented nodal matrices play an important role in the analysis of different features of electrical circuit models. Their study can be addressed in an abstract setting involving two- and three-colour weighted digraphs. By means of a detailed characterization of the structure of proper and normal trees, we provide a unifying framework for the rank analysis of augmented matrices. This covers in particular Maxwell’s tree-based determinantal expansions of (non-augmented) nodal matrices, which can be considered as a one-colour version of our results. Via different colour assignments to circuit devices, we tackle the DC-solvability problem and the index characterization of certain differential–algebraic models which arise in the nodal analysis of electrical circuits, extending several known results of passive circuits to the non-passive context.

International audience; In this article, we investigate the bifurcation and chaos in a simplest fractional-ordermemristor-based electrical circuit composed of only three circuit elements: a linear passive capacitor,a linear passive inductor and a non-linear active memristor with two-degree polynomial memristanceand a second-order exponent internal state. It is shown that this fractional circuit can exhibita drastically rich non-linear dynamics such as a Hopf bifurcation, coexistence of two, three and fourlimit cycles, double-scroll chaotic attractor, four-scroll chaotic attractor, coexistence of one (or two)chaotic attractor with one limit cycle and new chaotic attractor which is not observed in the integercase. Finally, the presence of chaos is confirmed by the application of the recently introduced 0–1test.

A low-cost multi-channel frequency response analyser (FRA) has been developed based on a DAQ (data acquisition)/LabVIEW interface. The system has been tested for electric and electrochemical impedance measurements. This novel association of hardware and software demonstrated performance comparable to a commercial potentiostat / FRA for passive electric circuits. The software has multichannel capabilities with minimal phase shift for 5 channels when operated below 3 kHz. When applied in active (galvanostatic) mode in conjunction with a commercial electronic load (by discharging a lead acid battery at 1.5 A) the performance was fit for purpose, providing electrochemical information to characterize the performance of the power source.

Çamlıbel, Mehmet Kanat (Dogus Author) -- Conference full title: 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009; Shanghai; China; 15 December 2009 through 18 December 2009 Instantaneous charge/flux transfers may occur in switched electrical circuits when the switch configuration changes. Characterization of such state discontinuities is a classical issue in circuit theory which, typically, is based on the so-called charge and flux conservation principle. This paper proposes a general state transfer principle for arbitrary switching port-Hamiltonian systems. This new principle coincides with the charge and flux conservation principle in the special case of linear RLC circuits, but also covers circuits with nonlinear capacitors and inductors, and of arbitrary topology. Moreover, the new principle is applied to switching mechanical systems.