Saturation Current Research Articles

Mathematical modeling and extraction of parameters of solar photovoltaic module based on modified Newton–Raphson method

This paper presents a numerical method for estimating four physical parameters of a single-diode circuit model based on manufacturer’s datasheet. A system of four non-linear equations are formed based on three key points of PV characteristics. The photocurrent, saturation current, ideality factor and the series resistance are solved iteratively using the proposed method. The suggested method is validated using RTC France solar cell, Chloride CHL285P and Photowatt PWP210 modules and the results are verified with respect to the in-field outdoor measurements. The proposed method shows a good agreement with the experimental data. Lastly, The model chosen is simulated under MATLB environment to assess the effects of external physical weather conditions, that is, temperature and solar irradiance. The advantage of the proposed method with respect of existing numerical techniques is that it converged faster than the widely used Newton method. Modeling of PV cell/module is essential in predicting performance of photovoltaic generators at any operating condition.

A New Approach to Current Transformer Saturation Compensation for Transmission Line Differential Protection

A non-linear autoregressive network with external inputs (NARX) model to reconstruct the current transformer (CT) secondary waveform distortion in the presence of protected transmission lines is presented. The qualitative analysis carried out on the autonomous model reveals the accurate performance of the current differential relay, because of the ability of the NARX to make accurate predictions and signal reconstruction even when faced with noisy or incomplete datasets. The suggested method uses samples of the line-protected remote current signal to produce a desired waveform. The unsaturated section is artificially expanded because it can estimate up to one sample after saturation with a respectable level of accuracy. The proposed method is evaluated by MATLAB and PSCAD software. The effectiveness of the suggested method for different fault types under varied situations has been proved. The simulation outcome confirms the method’s high accuracy concerning the unusual system conditions in the presence of CT saturation.

Adaptation and comparative analysis of HSPICE level‐61 and level‐62 model for a‐IGZO thin film transistors

AbstractThis paper presents a Computer‐aided design (CAD) model for a‐IGZO thin film transistors (TFTs) by adapting SPICE level‐61 RPI a‐Si: H (Hydrogenated Amorphous Silicon) TFT model and level‐62 RPI Poly‐Si (Poly Silicon) TFT model. This work provides a complete understanding of SPICE level‐61 and 62 model parameters, which must be tuned for a‐IGZO TFT simulation. The adapted SPICE models of level‐61 and level‐62 could model all regions of operation of the TFT, that is, above‐threshold and below‐threshold regions. Adapted RPI poly‐Si model also shows the kink effect in ZnO thin film transistors (TFTs) due to the recombination of electron–hole pairs in the channel via boundary trap states present in the poly‐Si TFTs thereby increasing the drain current in the transistors above pinch‐off region. The extracted performance parameters of the adapted models were found to be contiguous with experimental results. The maximum deviation in the subthreshold slope is approximately 5 mV/decade for level‐61 a‐Si TFT, and for level‐62 poly‐Si TFT, deviation in the subthreshold slope is even less, that is, 0.2 mV/decade. The experimental and simulated characteristics, extracted on‐to‐off ratio, negative bias reverse saturation current, and threshold voltage were almost similar. However, an average deviation of 2.4% and 2.27% was observed in the output characteristics of the adapted level‐61 and level‐62 models, respectively.

2.5 A/mm/350 GHz aggressively scaled gate engineered Fe-doped AlN/GaN channel HEMT with graded InGaN Backbarrier on SiC-wafer for next generation RF power electronics applications

This study intends to investigate the effects of barrier scaling, a crucial RF GaN-HEMT design element, which is imperative to achieve enhanced performance at nano-scale dimensions. From the performance characterization of the designed 50 nm recessed gated Fe-doped AlN/GaN/SiC HEMT featuring graded InGaN-back barrier (BB), the highest transconductance of 464.7 mS/mm, a maximum fT of 351.5 GHz, peak ID of 1.596 A/mm, & high drain saturation current of 2.527 A/mm at VGS = 3 V is observed for a 6 nm thin AlN barrier due to better gate control, and aided quantum well confinement because of Fe-doped buffer & graded InGaN BB. We observed that as barrier thickness increases, threshold voltage (Vth) becomes more negative and performance is deteriorated due to poor aspect ratio. This work also examines the role of gate-engineering on the electrical properties of the designed HEMT by employing different metals. The TCAD analysis indicates that the Al-gate HEMT had better DC/RF performance because of its lower ϕm (work-function). The performance declines and Vth increases as the Schottky barrier raises due touplifting of the conduction band edge. Since, it is crucial to understand the contribution of Rs & Rd in RF design, so in addition, we have done simulations by scaling source-gate gap (LGS), & drain-gate gap (LGD). It was found that the HEMT delivered better performance at the smallest LGS & LGD due to minimal Rs & Rd. The incredible performance of the novel HEMT reflects enhanced electron transport properties and implies that it possesses the capability of being extremely desirable for future aviation, military, and space applications.

Simulation and numerical modeling of high performance CH3NH3SnI3 solar cell with cadmium sulfide as electron transport layer by SCAPS-1D

This work includes the numerical modeling (NM) of solar cells consisting of the active layer of CH3NH3SnI3 and electron transport layer of CdS, by employing a software SCAPS-1D. Organic-inorganic lead-based perovskites are superior in terms of power conversion efficiency. However, there are some serious drawbacks associated with them including poor stability, shorter life time and toxicity. Therefore, it is the demand of the hour to explore alternative materials to overcome these shortcomings. In this regard, tin is a competitive alternative to lead because it has similar electronic and chemical properties. Moreover, it is nontoxic, making it environmentally friendly. However, Sn based perovskite devices are reported with inferior power conversion efficacy, to date. In the present work, we have worked on a novel architecture of solar cells containing CH3NH3SnI3 as a light absorber layer and CdS as electron fetching layer. Optimization of the device was performed numerically by varying physical parameters related to the active layer such as thickness, defect density and shallow acceptor concentration. The proposed architecture of solar cells was proved as an efficient system with Jsc of 33.40 mA/cm2, Voc of 0.878 V, FF of 85.25 %, and PCE of 25.02 %. The temperature analysis has revealed that, temperature higher than 300 K increases the reverse saturation current, seriously degrading the structure of the device, hence limiting the power conversion performance of the solar cell. Furthermore, a rear electrode made of the high work function materials like Pt forms an ohmic junction at the HTL/anode interface, enhancing the performance of the device. Results of this study have paved the way for experimentalists to explore opportunities, to rationalize this architecture for real time applications such as inhouse lighting and laptop/smartphone charging.

Using Recycled Tetrapak and Doped Titanyl/Vanadyl Phthalocyanine to Make Solid-State Devices.

In this work we studied the semiconductor behavior of titanyl phthalocyanine (TiOPc) and vanadyl phthalocyanine (VOPc), doped with anthraflavic acid and deposited on Tetrapak/graphite as flexible electrodes. The molecular structure was approached using the density functional theory and astonishingly, it was found that the structure and electronic behavior can change depending on the metal in the phthalocyanine. Experimentally, the Root Mean Square was found to be 124 and 151 nm for the VOPc-Anthraflavine and TiOPc-Anthraflavine films, respectively, and the maximum stress was 8.58 MPa for the film with VOPc. The TiOPc-Anthraflavine film presents the smallest fundamental gap of 1.81 eV and 1.98 eV for indirect and direct transitions, respectively. Finally, the solid-state devices were fabricated, and the electrical properties were examined. The tests showed that the current-voltage curves of the devices on Tetrapak and VOPc-Anthraflavine on a rigid substrate exhibit the same current saturation behavior at 10 mA, which is achieved for different voltage values. Since the current-voltage curves of the TiOPc-Anthraflavine on a rigid substrate presents a defined diode model behavior, it was approximated by nonlinear least squares, and it has been determined that the threshold voltage of the sample for the different lighting conditions is between 0.6 and 0.8 volts.

Thermal dependence on electrical characteristics of Au/(PVC:Sm2O3)/n-Si structure

In this study, we investigated the current–voltage (I–V) characteristics of Au/n-Si structure with an interfacial layer of Samarium Oxide (Sm2O3) nanoparticles (NPs) in polyvinyl chloride (PVC) matrix within a temperature range of 80–320 K. Applying the thermionic emission (TE) theory, essential electrical parameters such as reverse saturation current (I0), ideality factor (n), zero bias barrier height (ΦB0), series resistance (Rs), and rectification rate (RR) were carefully derived from the I–V data. The mean values of BH and Richardson constant obtained from the modified Richardson plot were determined to be 0.730 eV and 111.4 A/(cmK)2, respectively. Remarkably, this A* value closely matches its theoretical counterpart for n-type Si. Thus, our findings successfully highlight the effectiveness of the thermionic emission (TE) mechanism with the Gaussian distribution of BHs in explaining the I-V-T characteristics of the fabricated Schottky structure, shedding light on the intricate interplay between temperature and diode behavior. These insights offer valuable guidance for designing and optimizing thermal-sensitive devices based on this innovative structure.

Improvement of performance of perovskite solar cells through BaTiO<sub>3</sub> doping regulated built-in electric field

The preparation of hybrid perovskite solar cells is expensive and environmentally demanding. Carbon-based HTL-free perovskite solar cells (C-PSCs) have attracted much attention because they replace the expensive precious metal electrode and remove the poor stability of the hole transport material. However, the improvement of efficiency is hampered by poor carrier separation and transport performance within C-PSCs, while the enhancement of the built-in electric field can improve the carrier transport performance, thus enhancing photoelectric performance. The built-in electric field can be regulated by doping. The anomalous photovoltaic effect and the built-in electric field of ferroelectric material play an important role in the field of optoelectronics. In this work, a simple and effective method is developed to improve the performance of perovskite solar cells via the combination of internal doping of ferroelectric polymer and external control of electric field. Ferroelectric material barium titanate (BaTiO<sub>3</sub>) powder is added into perovskite precursor solution as an additive to prepare C-PSCs, which can improve the perovskite film morphology, reduce the film defect density, and enhance the carrier transport performance of C-PSCs. The results show that when the addition of BaTiO<sub>3</sub> is 1.0% (mass fraction), the perovskite film is uniform and dense, and the photoelectric conversion efficiency of the cell is the highest. After the forward voltage polarization treatment, the residual polarized electric field of ferroelectric material BaTiO<sub>3</sub> increases the built-in electric field, which provides sufficient power for realizing carrier transport and extraction, thus inhibiting the occurrence of non-radiative recombination. At the same time, the depletion layer width is increased, and the reverse saturation current is reduced, so the cell performance is significantly improved. The optimal device efficiency is 9.02%. This work provides an efficient strategy for regulating the built-in electric field by doping perovskite absorption layer.

Modeling of temperature effect on DC characteristics of microwave GaN devices

Due to the advantages of high power density, high efficiency, and great potential in extreme temperature environments, the GaN high electron mobility transistor (HEMT) device is widely used in circuit systems at high or low temperatures. However, its electrical performance is sensitive to the ambient temperature. Therefore, it is essential to build a model that can accurately characterize the electrical performance of GaN HEMTs at different ambient temperatures, which is also essential for precise circuit design. With the analysis of experiment and theory on the GaN HEMT at different ambient temperatures, an improved model for temperature effect on the DC characteristics of the GaN HEMT is proposed based on EEHEMT model. Considering the influence of the ambient temperature on electrical properties of the GaN HEMT, such as the threshold voltage, the knee voltage, and the saturated current, the model establishes a temperature-dependent function for key parameters in the formula of the drain-source current. Through Verilog-A implementation and simulation on the ICCAP software, the improved model accurately reflects the trend of the electrical performance changes of the GaN HEMT at different ambient temperatures. To further verify the model in this work, the on-wafer measurements at different temperatures including –55, –25, 25 and 75 ℃ are carried out for GaN HEMTs with different sizes, which are developed by Nanjing Electronic Devices Institute. Compared with the measured data, the output characteristics and the transfer characteristics simulated by the proposed model are accurate in an ambient temperature range of –55–75 ℃, with a relative fitting error less than 5%. The result shows that the improved model is of guiding significance in analyzing the direct current performance and high reliability design of circuits at different temperatures.

Precise mode control of mid-infrared high-power laser diodes using on-chip advanced sawtooth waveguide designs

Abstract Power scaling in conventional broad-area (BA) lasers often leads to the operation of higher-order lateral modes, resulting in a multiple-lobe far-field profile with large divergence. Here, we report an advanced sawtooth waveguide (ASW) structure integrated onto a wide ridge waveguide. It strategically enhances the loss difference between higher-order modes and the fundamental mode, thereby facilitating high-power narrow-beam emission. Both optical simulations and experimental results illustrate the significant increase in additional scattering loss of the higher-order modes. The optimized ASW lasers achieve an impressive output power of 1.1 W at 4.6 A at room temperature, accompanied by a minimal full width at half maximum lateral divergence angle of 4.91°. Notably, the far-field divergence is reduced from 19.61° to 11.39° at the saturation current, showcasing a remarkable 42% improvement compared to conventional BA lasers. Moreover, the current dependence of divergence has been effectively improved by 38%, further confirming the consistent and effective lateral mode control capability offered by our design.

Investigation of electrical, dielectric and interface state densities of Al/p-Si structures with PTCDA interlayer under different light intensities

In our study; we investigated illumination intensity-dependent electrical and dielectric properties of the Al/p-type Si metal-semiconductor (MS) structures with perylenetetracarboxylic dianhydride (PTCDA) interface using current-voltage (I–V) and capacitance-conductance-voltage (C-G/ω--V) measurements. Thin film layer with PTCDA interface was coated on p-type Si by Spin Coating method. The structure of PTCDA organic semiconductor powder examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrical parameters such as ideality factors (n), barrier heights (Φbo), rectification ratios (RR), saturation currents (I0) and series resistances (RS) were obtained from both thermionic emission (TE) theory and Cheng theory and compared with each other. Dielectric properties such as dielectric constant (ε′), dielectric loss (ε''), loss tangent (tanδ), electrical conductivity (σac), and interface state densities (NSS) were obtained from C–V and G/ω-V measurements. It was seen that the values of ε′, ε'', tanδ, and NSS decreases with increasing illumination while σac increase with increasing illumination intensity. Experimental results show that Al/PTCDA/p-type Si semiconductor structure can improve efficiency in electronic devices.

IMPROVEMENT OF THE METHOD OF CALCULATINGTHE PARAMETERS OF THE INDUCTION MOTORS REPLACEMENT SCHEME

The optimization of the equivalent circuit parameters of a three-phase induction motor with an equivalent double-circuit rotor is presented. The initial parameters of the equivalent circuit are estimated using a method known as engineering, based on the data provided in the manufacturer’s data sheet. The purpose of the work is aimed at increasing the accuracy of calculating currents and torques when using a double-circuit equivalent circuit of an induction motor by improving the method for determining the parameters of the equivalent circuit. A procedure for optimizing parameters has been developed to reduce errors between the calculated and actual values of the motor torque and current. Achieving the goal is ensured through the use of the author’s method of taking into account the nonlinearities of the motor, namely saturation of the magnetic circuit along the main path and scattering paths. To analyze the characteristics of an induction motor and predict its behavior in the event of faults and various operating modes, it is necessary to create a mathematical model of this motor. To ensure the adequacy of model calculations, it is necessary to take into account various nonlinearities of an induction motor, such as the effects of current displacement and machine saturation, steel losses, and others. The choice of a specific nonlinearity to take into account, as well as the methodology for taking it into account, are determined by the complexity of the tasks posed to the model. The depth of taking into account the nonlinear parameters of an induction motor depend on the requirements for the accuracy of the analysis and necessarily includes taking into account the most significant factors affecting the performance of the machine. A universal mathematical model has been created that describes an induction motor in a coordinate system that is stationary relative to the stator and takes into account the nonlinearity of its parameters. The parameters of the equivalent circuit of twelve industrial induction motors without and with optimization were assessed. A comparison was made of the results obtained from the engineering method and the actual data of the manufacturer to verify the effectiveness of the proposed method. Keywords: induction motor, nonlinearity of IM parameters, manufacturer’s data, optimization, parameter estimation, squirrel cage, mathematical modeling, experimental studies

ՀՊՏՀ ուսանողների բավարարվածության գնահատում / Assessment of student satisfaction of ASUE

In the current market saturation, studying the factors affecting consumer behavior and evaluating their impact has become imperative for any manufacturer. The key to success lies in greater awareness of consumers' psychographic characteristics, opinions, attitudes, inner world, aspirations, perceptions and satisfaction. The field of educational services is no exception. The quality of the educational process is directly related to the students' motivation, which is formed as a result of their satisfaction. In particular, in universities, it is necessary to conduct research among students to identify the factors affecting their satisfaction, evaluate these factors, and develop strategies to increase satisfaction. The paper is dedicated to studying and evaluating the factors affecting the satisfaction of undergraduate students at ASUE. Information about factors characterizing almost all aspects of the university life of students in all majors and faculties of the university was collected and analyzed. Using the method of factor analysis , these factors were grouped into three basic categories. The value of each category was clarified by course and faculty. In the paper, with the help of the Net Promoter Score method, student satisfaction was investigated The NPS index was calculated, and measures aimed at increasing student satisfaction were proposed.

Features of localization of remaining oil in terrigenous reservoirs and potential for their recovery at the final stage of field development

The paper considers one of the unique fields in terms of geological reserves. The paper also analyzes the development of the D3ps formation sections of the Devonian terrigenous layer of the studied field. A detailed geological and hydrodynamic model was constructed based on the consolidation of all available information. An integrated analysis of actual well performance data, field geophysical tests, geological and technical measures, results of infill drilling, as well as geological and hydrodynamic modeling confirmed the localization of reserves primarily in the upper bed of D3ps.1. The analysis of all performed studies revealed higher values of current oil saturation in the upper bed – up to 0.8 unit fractions and lower values in the lower bed – up to 0.68 unit fractions. Similar results were obtained from 87 sidetracks. Drilling of wells and sidetracks is proposed in areas with no well stock. Despite the final stage and high degree of field development, the proposed strategy will support oil production levels, increase remaining recoverable reserves, increase the efficiency of reserve recovery and improve the economic performance of field development. The introduction of modern development technologies, approaches to the analysis and monitoring of development will increase the target value of the final recovery factor from 0.608 to 0.613 unit fractions, which, with a significant amount of in-place reserves, made it possible to increase the remaining recoverable reserves by 35%. The strategy will make it possible to achieve higher oil recovery rates. The approaches used to solve the tasks set in the study can be applied to the fields of the Volga region.

Development of charge-discharge circuitry based on supercapacitor and its application to limiter probe diagnostics in EAST

The EAST limiter probe is installed on the front surface of guard limiter, which consists of two columns and can operate in floating potential mode, ion saturation current mode, and swept single-probe mode simultaneously. When Langmuir probe operates in the ion saturation current mode, it requires a stable biasing voltage. To meet this requirement, a large capacitor is used to provide a biasing voltage for the probe. Comparing with the 9 V dry batteries that are commonly used in magnetic confinement fusion devices, employing a large capacitor offers advantages such as flexible voltage adjustment, easy maintenance, and environmental friendliness. Therefore, we have designed and tested a complete set of supercapacitor charge-discharge control circuitry. In this work, a control software is developed for the supercapacitor charge-discharge control circuitry based on the Python language to enable the remote and automatic controlling of the circuitry operation. As demonstrated in experiments, the capacitor charge-discharge control circuitry can supply stable biasing voltage output for the probe under long-pulse discharge, and it is workable in complex electromagnetic environment of magnetic confinement fusion device. By implementing the supercapacitor charge-discharge control circuitry in EAST limiter probe diagnostics, the three-dimensional distributions of plasma parameters are measured, such as ion saturation current, floating potential, electron temperature, and plasma density. In a lower hybrid wave (LHW) heating experiment, the 2.45 GHz LHW is found to generate larger electron density than the 4.6 GHz LHW, and the largest electron density appears when both the 2.45 GHz and 4.6 GHz LHWs are turned on simultaneously. These experimental results confirm that supercapacitor charge-discharge control circuitry can be operated reliably and stably.

An AlGaN-GaN HEMT with p-GaN Extended Gate for Improvements on Current Dispersion and Breakdown Characteristics

This study introduces a novel p-GaN/AlGaN/GaN heterostructure wafer, implementing a unique p-type GaN gate AlGaN/GaN HEMT configuration. In this design, the p-GaN region extends toward the drain, eliminating the need for a gate electrode. This innovation significantly enhances the HEMT’s performance, with a 45.2% increase in breakdown voltage (BV) and a 17% higher threshold voltage (VTH) compared to conventional p-GaN gate HEMTs. The extended gate design redistributes the electric field, acting as a field plate to elevate the breakdown voltage. Furthermore, the proposed device, by reducing 17.4% of the saturation current without increasing the on-resistance, possibly offers improved short-circuit capability.

Design-Oriented Analysis and Transient Control for VSG with Current Saturation Unit

Design-Oriented Analysis and Transient Control for VSG with Current Saturation Unit

Transient Stability Analysis and Damping Enhanced Control of Grid-Forming Wind Turbines Considering Current Saturation Procedure

Transient Stability Analysis and Damping Enhanced Control of Grid-Forming Wind Turbines Considering Current Saturation Procedure

Calcium chloride as an ionic response modulator in metal–organic framework-modified nanochannels (MOF@SSNs): enhancing ionic current saturation and selectivity

Ionic transport in polyethylene terephthalate (PET) nanochannels modified with UiO-66 MOF was modulated by CaCl2. Ca2+ selective binding to carboxylate moieties enhances surface charge triggering an ionic current saturation regime.

GAMMA AND ELECTRO-LOGGING DURING WELL WORKOVER USING THE TECHNOLOGY OF RADIAL BRANCHING OF FORMATION

The efficiency of oil recovery from oil-bearing reservoirs by modern, Abstract. industrially developed development methods in most oil-producing countries today is considered unsatisfactory, and the final oil recovery of reservoirs in various countries and regions averages from 25 to 40 %. For example, in Latin America and Southeast Asia, average oil recovery is 24–27 %, in Iran — 16–17 %, in the USA, Canada and Saudi Arabia — 33–37 %, in the CIS countries and Russia — up to 40 %, depending on the structure of oil reserves and the development methods used [1].Therefore, the task of managing the productivity of oil and gas reservoirs remains relevant at present.The article discusses a special technology for the use of gamma and electro-logging as part of the Perfobur technical system (hereinafter referred to as pyrolysis oil). These geophysical methods of investigation, at the end of drilling radial channels over a small diameter and radius of curvature, performed with trajectory control, make it possible to prove that drilling was carried out in a given reservoir, and provide more detailed information about its productivity.One of the areas of use of pyrolysis oil is enhanced oil recovery, intensification of inflow, restoration of normal operation of wells stopped or hindered due to falling at the bottom of oil field equipment, blocking or contamination of the perforation zone, including during initial penetration [2–5].Complex geological conditions are noted, such as high reservoir fragmentation, heterogeneity of the carbonate reservoir, fracturing, large lateral permeability variability, high oil viscosity and presence of washed zones, caverns after salt-acid treatment (SW) with subsequent steam injection. Under such conditions, it is difficult to develop a field, new well logging methods are required, as well as high-quality logging to determine saturated interbeds. Effective development of the field requires the determination of the current reservoir saturation with higher accuracy, which will help the subsoil user to better develop the field, eliminate stimulation of watered beds, and carry out better and more selective intensification of interbeds. It should be noted that the presence of a steel column practically eliminates the possibility of using electrical logging methods. Therefore, it is recommended to use such methods in an open hole. Drilling of radial channels using the Perfobur technology allows electro-logging with a special tool due to the possibility of repeated entries into the drilled channels [2–5].