Electrical Modeling of a Silicon Photovoltaic Solar Cell: Comparative Study of Models Characterizing the Photovoltaic Solar Cell

In this article we make a detailed study and a presentation of the different models of circuit’s equivalent to silicon-based photovoltaic solar cells. Starting from a real solar cell and real phenomena from the manufacture of the cell to the production of current by the cell. A comparison of the models with a real experimental method is carried out. The comparison is based on an overlay of the results. The study allowed us to choose the most suitable model. We are interested in the losses by leaks and the losses due to the development of the cell. In fact, we studied the influence of the shunt resistance on the current-voltage characteristic and the electrical power.

ANALYSIS OF STRESS FIELD NEAR CRACK TIP BASED ON ELECTRIC SATURATION MODEL

Within the framework of nonlinear eleetroelasticity, the stress field near to the crack tip in an infinite piezoelectric media subject to a far field uniform loading is studied by using an electrical strip saturation model and the complex variable method. And the emphasis is placed on the stress field near to the crack tip. The obtained solutions show that the normalized stress components at an arbitrary point near to the crack tip are determined by the angle of the point. Moreover, the stress components are independent of the distance from the point to the ori- gin of the coordinate. The distributions of in-plane stress components near to the crack tip are analyzed based on numerical results for PZT-SH. Compared with some related solutions, results show that the solutions are valid.

Modeling of electrode system for three-phase electric arc furnace

To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the practical situation. They are the power supply system model the electric arc model and the hydraulic actuator system model. According to the basic circuit theory, the power supply system model where the high voltage transmission circuit and mutual inductances were considered, was set up. The electric arc model, which was novel for the electrode control, served as the electrical load and was connected to the power supply system model. The hydraulic actuator system model consists of the proportional valve part that is modeled to capture the dead-zone nonlinear characteristics and the hydraulic cylinder part where the impact of the load force is taken into account. By comparing simulation data and actual data, the results show that the electrode system model is proved to be accurate.

Molecular properties and potential energy function model of BH under external electric field

Using the density functional B3P86/cc-PV5Z method, the geometric structure of BH molecule under different external electric fields is optimized, and the bond lengths, dipole moments, vibration frequencies, and other physical properties parameters are obtained. On the basis of setting appropriate parameters, scanning single point energies are obtained by the same method and the potential energy curves under different external fields are also obtained. These results show that the physical property parameters and potential energy curves may change with external electric field, especially in the case of reverse direction electric field. The potential energy function without external electric field is fitted by Morse potential, and the fitting parameters are obtained which are in good agreement with experimental values. In order to obtain the critical dissociation electric parameter, the dipole approximation is adopted to construct a potential model fitting the corresponding potential energy curve of the external electric field. It is found that the fitted critical dissociation electric parameter is consistent with numerical calculation, so that the constructed model is reliable and accurate. These results will provide important theoretical and experimental reference for further studying the molecular spectrum, dynamics, and molecular cooling with Stark effect.

Model Transformer Evaluation of High-Permeability Grain-Oriented Electrical Steels

The dependence of transformer performance on the material properties was investigated using two laboratory-processed 0.23 mm thick grain-oriented electrical steels domain-refined with elec-trolytically etched grooves having different magnetic properties. The iron loss at 1.7 T, 50 Hz and the flux density at 800 A/m of material A were 0.73 W/kg and 1.89 T, respectively; and those of material B, 0.83 W/kg and 1.88 T. Model stacked and wound transformer core experiments using the tested materials exhibited performance well reflecting the material characteristics. In a three-phase stacked core with step-lap joints excited to 1.7 T, 50 Hz, the core loss, the exciting current and the noise level were 0.86 W/kg, 0.74 A and 52 dB, respectively, with material A; and 0.97 W/kg, 1.0 A and 54 dB with material B. The building factors for the core losses of the two materials were almost the same in both core configurations. The effect of higher harmonics on transformer performance was also investigated.

MODELING AND IMPLEMENTATION OF SPEED GOVERNOR FOR THE HYBRID ELECTRIC VEHICLE ENGINE

A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.

Electrical model parameters identification of radiofrequency discharge in argon through 1D3V/PIC-MC model

This work represents a contribution to the modeling of a radiofrequency（RF） discharge in argon at low pressure（from 25 to 200 mTorr）.It is started by the validation of the collision cross sections used in the particle model through a comparison between the transport coefficients calculated by these data and the measurements of the transport coefficients already exist in the literature,the particle model is also validated by a comparison between the calculated plasma density and that measured in the literature.The electrical model proposed in this work consists of replacing the RF discharge by a passive circuit（resistance in series with a capacitor）,where the resistance represents the plasma medium and the obstruction of the passage of the electronic current,and the capacitor represents the sheaths and the appearance of the displacement current in these regions.The parameters of the electrical model are obtained through particle modeling.The electrical model presented accurately reproduces the current of the discharge,but without considering the phenomenon of distortion.The total harmonic distortion rate follows the variation of the plasma density;its maximum value is 5.75% at 100 mTorr.

Applying Improved Electrical Breakdown Model to Study Insulating Property of c-C_4F_8/N_2 Gas Mixture

Perfluorocyclobutane(c-C4F8) has been recently considered as a potential alternative to SF6,because of its high electro-negativity and extremely low environmental effect.However,due to its high boiling point,c-C4F8 should mixed with buffer gases such as N2 or CO2 in order to avoid the liquefaction at low temperature.This paper investigates insulating properties of c-C4F8/N2 gas mixtures from two aspects including electrical strength,and Global Warming Potential(GWP).Moreover,improved electrical breakdown model of gas mixtures is founded.Breakdown temperature and breakdown electrical field in gas mixtures can be obtained from rigorous Townsend criterion expression according to gas mixtures ratio and cross section data of gas mixtures in this model.Under the condition of different gas pressure(0.1~0.4 MPa),gas mixtures ratio(0～30%),and electrode gap(2~10 mm),breakdown voltages of gas mixtures are calculated by using of this model.Insulation strength of SF6/N2 mixed gas is compared with c-C4F8/N2 mixed gas in the same conditions.Research results show that theoretical computation corresponds with experiment.If the content of c-C4F8 or SF6 in mixtures is less than 30%,insulation strength between c-C4F8/N2 and SF6/N2 is very close.Considering two indexes(breakdown voltage,GWP),it is suitable for c-C4F8 content being 15%～20% in c-C4F8/N2 gas

Research on the Static Magnetic Field of Ships with Corrosion and Anticorrosion Efficacy Using Electric Dipole Model

In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships.

A Model for Anion Electric Adsorption on Variable Charge Soils

A model was established for anion electric adsorption on variable charge surfaces and an equation to describe the relationship of adsorption amount with equalibrium concentration and suspension pH was derived according to the principles of surface reaction between variable charge surface and anions.The adsorption behaviours of nitrate and chloride on variable charge soils were modelled and the results showed that the model could describe the adsorption of nitrate very well.

Efficiency of Model Induction Motor Using Various Non-Oriented Electrical Steels

The performance of a 3-phase 6-pole 400 W inverter-drive induction motor was investigated using a variety of non-oriented electrical steels for stator core at PWM inverter fundamental wave frequencies of 30 to 300 Hz. There existed an optimum Si content of the material depending on the tooth flux density. Both reduction of material thickness and stress-relief annealing of the stator core improved the motor efficiency. The influence of Si content on the efficiency was small at lower PWM frequencies, while at higher frequencies the motor efficiency increased with increasing Si content. The Cu loss WC increased and the Fe loss Wi counteractiveiy decreasedwith increasing Si content at lower frequencies; while at higher frequencies Wi had dominant effect on the efficiency. Newly developed materials RMA, having lower Fe losses after stress-relief annealing and higher flux densities with lower Si contents, showed motor efficiencies superior to conventional J1S grade materials with comparable Fe losses.

Three-dimensional magnetotelluric modeling in the spherical and Cartesian coordinate systems:A comparative study

With the increase in the coverage area of magnetotelluric data,three-dimensional magnetotelluric modeling in spherical coordinates and its differences with respect to traditional Cartesian modeling have gradually attracted attention.To fully understand the influence of the Earth’s curvature and map projection deformations on Cartesian modeling,qualitative and quantitative analyses based on realistic three-dimensional models need to be examined.Combined with five representative map projections,a type of model conversion method that transforms the original spherical electrical conductivity model to Cartesian coordinates is described in this study.The apparent resistivity differences between the spherical western United States electrical conductivity model and the corresponding five Cartesian models are then compared.The results show that the cylindrical equal distance map projection has the smallest error.A meridian convergence correction resulting from the deformation of the map projection is introduced to rotate the Cartesian impedance tensor from grid north to geographic north,which reduces differences from the spherical results.On the basis of the magnetotelluric field data,the applicability of the Cartesian coordinate system to western and contiguous United States models is quantitatively evaluated.Precise interpretations of the contiguous United States model were found to require spherical coordinates.

A novel three-dimensional electric ophthalmotrope for improving the teaching of ocular movements

AIM: To develop a novel three-dimensional(3D) electric ophthalmotrope to improve the ophthalmology teaching effectiveness and evaluate the teaching value. METHODS: A 3D electric ophthalmotrope was designed by simulating the movement of the ocular and the extraocular muscles according to Sherrington’s law. The model with joint bearing was to ensure the flexibility and centripetal rotation of the simulated ball and stepper motor as the driving device. A programmable processor was used to control the motion amplitude of the stepper motor. The size of hole was set at the back of the simulated shell to limit the amount of eye movement. Afterwards, using a 5-point Likert scale, 7 experts evaluated the 3D electric ophthalmotrope’s simulation ability and precision, compared with the traditional anatomical model. In addition, the teaching effectiveness of the 3D electric ophthalmotrope was evaluated at in-class quiz and final exam in a randomized controlled trial. RESULTS: The 3D electric ophthalmotrope could be operated easily to demonstrate the eye movements with motion of different ocular muscles. The experts agreed that the 3D electric ophthalmotrope was different from the traditional model and was easier for students to understand every extraocular muscles’ movement in each evaluation index(P<0.05). Moreover, the results of teaching effectiveness showed that the 3D electric ophthalmotrope were significantly greater than the traditional model both at in-class quiz(P<0.01) and final exam(P<0.05). CONCLUSION: This novel 3D electric ophthalmotrope is better than the traditional model, which can be to improve the ophthalmology teaching effectiveness for students to understand the extraocular muscles’ movement.

Mechanical and electrical properties of coarse-grained soilaffected by cyclic freeze-thaw in high cold regions

To evaluate the geotechnical properties of coarse-grained soil affected by cyclic freeze-thaw,the electrical resistivity and mechanical tests are conducted.The soil specimens are prepared under different water contents,dry densities and exposed to 0?20 freeze-thaw cycles.As a result,the stress?strain behavior of the specimen(w=14.0%andρd=1.90 g/cm^3)changes from strain-hardening into strain-softening due to the freeze-thaw effect.The electrical resistivity of test specimen increases with the freeze-thaw cycles change,but the mechanical parameters(the unconfined compressive strength qu and the deformation modulus E)and brittleness index decrease considerably at the same conditions.All of them tend to be stable after 7?9 cycles.Moreover,both the dry density and the water content have reciprocal effects on the freeze-thaw actions.The failure and pore characteristics of specimens affected by freeze-thaw cycles are discussed by using the image analysis method.Then,an exponential function equation is developed to assess the electrical resistivity of specimens affected by the cyclic freeze-thaw.Linear relations between the mechanical parameters and the electrical resistivity of specimens are established to evaluate the geotechnical properties of the soil exposed to freeze-thaw actions through the corresponding electrical resistivity.

An Improvement in Electrical Properties of Asphalt Concrete

Materials such as Koch AH-70,basalt aggregate,limestone powder and graphite particles were used to prepare conductive asphalt concrete,which is a new type of multifunctional concrete.The mix proportion by weight was shown as follows.Fine aggregates (2.36-4.75 mm)∶fine aggregates (<2.36mm)∶limestone powder∶asphalt=120∶240∶14∶30.The content of added graphite particles ranged from 0% to 20%(by the weight of asphalt concrete).A conductive asphalt concrete with a resistivity around 10-10 3Ω·m was obtained.Special attention was paid to the effects of graphite content,graphite physical-chemical properties,asphalt content and temperature on the resistivity.Furthermore,an attempt was made to develop an electrically conductive model for asphalt concrete.

Estimation Method of State-of-Charge For Lithium-ion Battery Used in Hybrid Electric Vehicles Based on Variable Structure Extended Kalman Filter

Since the main power source of hybrid electric vehicle（HEV） is supplied by the power battery,the predicted performance of power battery,especially the state-of-charge（SOC） estimation has attracted great attention in the area of HEV.However,the value of SOC estimation could not be greatly precise so that the running performance of HEV is greatly affected.A variable structure extended kalman filter（VSEKF）-based estimation method,which could be used to analyze the SOC of lithium-ion battery in the fixed driving condition,is presented.First,the general lower-order battery equivalent circuit model（GLM）,which includes column accumulation model,open circuit voltage model and the SOC output model,is established,and the off-line and online model parameters are calculated with hybrid pulse power characteristics（HPPC） test data.Next,a VSEKF estimation method of SOC,which integrates the ampere-hour（Ah） integration method and the extended Kalman filter（EKF） method,is executed with different adaptive weighting coefficients,which are determined according to the different values of open-circuit voltage obtained in the corresponding charging or discharging processes.According to the experimental analysis,the faster convergence speed and more accurate simulating results could be obtained using the VSEKF method in the running performance of HEV.The error rate of SOC estimation with the VSEKF method is focused in the range of 5% to 10% comparing with the range of 20% to 30% using the EKF method and the Ah integration method.In Summary,the accuracy of the SOC estimation in the lithium-ion battery cell and the pack of lithium-ion battery system,which is obtained utilizing the VSEKF method has been significantly improved comparing with the Ah integration method and the EKF method.The VSEKF method utilizing in the SOC estimation in the lithium-ion pack of HEV can be widely used in practical driving conditions.

Multi-objective planning model for simultaneous reconfiguration of power distribution network and allocation of renewable energy resources and capacitors with considering uncertainties

This research develops a comprehensive method to solve a combinatorial problem consisting of distribution system reconfiguration, capacitor allocation, and renewable energy resources sizing and siting simultaneously and to improve power system's accountability and system performance parameters. Due to finding solution which is closer to realistic characteristics, load forecasting, market price errors and the uncertainties related to the variable output power of wind based DG units are put in consideration. This work employs NSGA-II accompanied by the fuzzy set theory to solve the aforementioned multi-objective problem. The proposed scheme finally leads to a solution with a minimum voltage deviation, a maximum voltage stability, lower amount of pollutant and lower cost. The cost includes the installation costs of new equipment, reconfiguration costs, power loss cost, reliability cost, cost of energy purchased from power market, upgrade costs of lines and operation and maintenance costs of DGs. Therefore, the proposed methodology improves power quality, reliability and security in lower costs besides its preserve, with the operational indices of power distribution networks in acceptable level. To validate the proposed methodology's usefulness, it was applied on the IEEE 33-bus distribution system then the outcomes were compared with initial configuration.

Hard magnetization direction and its relation with magnetic permeability of highly grain-oriented electrical steel

The magnetic properties of highly grain-oriented electrical steel vary along different directions. In order to investigate these properties, standard Epstein samples were cut at different angles to the rolling direction. The hard magnetization direction was found at an angle of 60° to the rolling direction. To compare the measured and fitting curves, when the magnetic field intensity is higher than 7000 A/m, it is appropriate to simulate the relation of magnetic permeability and magnetization angle using the conventional elliptical model. When the magnetic field intensity is less than 3000 A/m, parabolic fitting models should be used; but when the magnetic field intensity is between 3000 and 7000 A/m, hybrid models with high accuracy, as proposed in this paper, should be applied. Piecewise relation models of magnetic permeability and magnetization angle are significant for improving the accuracy of electromagnetic engineering calculations of electrical steel, and these new models could be applied in further industrial applications.

Analysis and FDTD Modeling of the Influences of Microwave Electromagnetic Waves on Human Biological Systems

The interactions of electromagnetic waves with the human body are complex and depend on several factors related to the characteristics of the incident wave, including its frequency, its intensity, the polarization of the tissue encountered, the geometry of the tissue and its electromagnetic properties. That’s to say, the dielectric permittivity, the conductivity and the type of coupling between the field and the exposed body. A biological system irradiated by an electromagnetic wave is traversed by induced currents of non-negligible density;the water molecules present in the biological tissues exposed to the electromagnetic field will begin to oscillate at the frequency of the incident wave, thus creating internal friction responsible for the heating of the irradiated tissues. This heating will be all the more important as the tissues are rich in water. This article presents the establishment from a mathematical and numerical analysis explaining the phenomena of interaction and consequences between electromagnetic waves and health. Since the total electric field in the biological system is unknown, that is why it can be determined by the Finite Difference Time Domain FDTD method to assess the electromagnetic power distribution in the biological system under study. For this purpose, the detailed on the mechanisms of interaction of microwave electromagnetic waves with the human body have been presented. Mathematical analysis using Maxwell’s equations as well as bio-heat equations is the basis of this study for a consistent result. Therefore, a thermal model of biological tissues based on an electrical analogy has been developed. By the principle of duality, an electrical model in the dielectric form of a multilayered human tissue was used in order to obtain a corresponding thermal model. This thermal model made it possible to evaluate the temperature profile of biological tissues during exposure to electromagnetic waves. The simulation results obtained from computer tools show that the temperature in the biological tissue is a linear function of the duration of exposure to microwave electromagnetic waves.

Arc deflection model and arc direction control for DC arc furnace

Based on the analysis of three-dimensional power conductor for DC arcfurnace, the electric arc deflection model was set up and the control system of the arc directionwas configured. According to the bus bar distribution at the bottom electrodes cooled by water, thearc direction control principle and its configuration were described. The simulation results showthat the control system can restrain the electric arc deflection and control the arc direction.