Simulated Output Characteristics Research Articles

A novel high-dimensional and multi-physics modeling approach of proton exchange membrane fuel cell for real-time simulation

Fuel cell model provides state observation and quantitative analysis for Hardware-In-the-Loop (HIL) test platform. For a high-dimensional multi-physics model, the observed distribution of physical properties is meaningful for fuel cell stack optimization, manufacturing process and model-based control development. However, traditional modeling approach is difficult to consider both the calculation accuracy and efficiency. To solve this problem, this paper proposes a high-dimensional multi-physics real-time modeling approach for fuel cells based on partial differential equations (PDEs)-tridiagonal matrix equation transformation (TMET) and symmetric successive overrelaxation (SSOR) algorithm. In the proposed method, a generalized framework of TMET and a novel staggered grid technique is developed. In this case, both the convection and diffusion phenomena can be accurately described. For different fuel cells or parameters change, supplementary model modification or development is not required, only the global variables need to be re-assigned. Moreover, SSOR with bi-directional iteration mechanism is used to increase the probability of computational convergence and thus improve the calculation efficiency. Compared with commercial COMSOL model, by using the proposed modeling approach, the mean absolute percentage error (MAPE) of the simulated polarization output characteristics is 1.77%, the MAPE of different distribution characteristics can remain within 10%, and the calculation time can be shortened from hours even days to seconds.

Parameters identification and optimization of photovoltaic panels under real conditions using Lambert W-function

This paper proposes a new approach based on Lambert W-function to extract the electrical parameters of photovoltaic (PV) panels. This approach can extract the optimal electrical characteristics of the PV panel under variable conditions of irradiation and temperature. Three benchmarking panels (shell SP70 monocrystalline silicon, shell ST40 thin film, and KC200GT Polycrystalline Silicon) are demonstrated and analyzed considering the electrical characteristics provided by the manufacturers. A comprehensive assessment is carried out under different weather condition to validate the capability and the robustness of the proposed approach. Furthermore, the simulated output characteristics of the three modules Photovoltaic are almost comparable and reproduce faithfully the manufacturer’s experimental data The novelty of this study is the using a new hybrid analytical and numerical method that straight forward and effective given value of Root mean square error less than those obtained by others methods that indicate the estimated results are very close to the experimental values provided by the manufacturers.

Multi-Domain Modelling of LEDs for Supporting Virtual Prototyping of Luminaires

This paper presents our approaches to chip level multi-domain LED (light emitting diode) modelling, targeting luminaire design in the Industry 4.0 era, to support virtual prototyping of LED luminaires through luminaire level multi-domain simulations. The primary goal of such virtual prototypes is to predict the light output characteristics of LED luminaires under different operating conditions. The key component in such digital twins of a luminaire is an appropriate multi-domain model for packaged LED devices that captures the electrical, thermal, and light output characteristics and their mutual dependence simultaneously and consistently. We developed two such models with this goal in mind that are presented in detail in this paper. The first model is a semi analytical, quasi black-box model that can be implemented on the basis of the built-in diode models of spice-like circuit simulators and a few added controlled sources. Our second presented model is derived from the physics of the operation of today’s power LEDs realized with multiple quantum well heterojunction structures. Both models have been implemented in the form of visual basic macros as well as circuit models suitable for usual spice circuit simulators. The primary test bench for the two circuit models was an LTspice simulation environment. Then, to support the design of different demonstrator luminaires of the Delphi4LED project, a spreadsheet application was developed, which ensured seamless integration of the two models with additional models representing the LED chips’ thermal environment in a luminaire. The usability of our proposed models is demonstrated by real design case studies during which simulated light output characteristics (such as hot lumens) were confirmed by luminaire level physical tests.

Modeling of triboelectric charge accumulation dynamics at the metal–insulator interface for variable capacitive structures: application to triboelectric nanogenerators

This paper presents a dynamic model to study triboelectric charge accumulation in a variable capacitive structure with metal–dielectric interface. The presented model addresses a serious flaw of current published theoretical works related to modeling of triboelectric energy harvesters. Electrostatic analysis of the device in the contact and non-contact modes is performed. Based on the analysis of the non-contact mode, a novel technique is introduced to measure stable parasitic triboelectric charge density on the surface of the dielectric layer. Theoretical analysis for positive and negative charge accumulation is performed separately and key characteristic equations of both cases are extracted. A new measurement technique is developed to assess triboelectric charge build-up on the surface of the dielectric layer by employing a simple bridge rectifier as a test circuit. Based on the measured data, a time-dependent exponential model is suggested for triboelectric charge accumulation on the surface of the dielectric layer. The presented dynamic model is a vital asset in modeling dynamic output of triboelectric nanogenerators (TENG’s). The results show that failure to consider triboelectric charge dynamics in modeling of TENG’s would result in more than 50% error in the simulated output characteristics. Charge accumulation A new surface charge evaluation technique is introduced. Triboelectric charge accumulation on the surface of dielectrics is calculated and modeled using a simple half-wave rectifier. To get to the model, discrete charge-time points are measured. The dynamic charge model presents an essential asset in simulation of the output performance of TENG’s. positive and negative charge build up is measured.

Model and optimal design of 147Pm SiC-based betavoltaic cell

The method of Monte Carlo and numerical model co-simulation is adopted to research the radiation-voltaic effect in semiconductor device and used in the optimal design of 147Pm SiC-based cell in this paper. According to the energy spectrum of 147Pm, the ionization energy deposition in the cell is calculated by Monte Carlo method. The result is converted into the non-equilibrium carrier information and mapped into the device grid generated by the numerical software, so as to simulate output characteristics of the cell. The simulation results based on the SiC PIN betavoltaic cell show the conversion efficiency firstly goes up and then decreases as the I layer thickness increases, and the conversion efficiency decreases when the doping concentration of I layer increases. The conversion efficiency will be 3.74% when the doping concentration and thickness of I layer are 5 × 1014cm−3 and 20 μm respectively. According to the analysis, the recombination loss of radiation-induced carriers in I layer is the main factor influencing the improvement of conversion efficiency. To improve the conversion efficiency, the “graded N layer” SiC PN cell is proposed in this paper to replace conventional I layer with two N layers with different doping concentrations; the electric field is introduced to reduce the recombination loss of the radiation-induced carriers. The conversion efficiency will be 4.58% when the thickness of two layers are 10 μm and the doping concentrations are respectively 5 × 1014cm−3 and 1 × 1016cm−3.

Study of microwave damage effect on HEMT low noise amplifier under different drain voltage bias

The microwave damage effect on high electron mobility transistor (HEMT) low noise amplifier (LNA) under different drain voltage bias is studied using TCAD simulation and experiments. Simulation and experimental results suggest that the damage power thresholds and damage locations of single stage LNA under different drain voltage bias are almost the same. Nevertheless, the output power under zero drain bias is about 5.6dB higher than it under normal (3V) drain bias with the injection of large power microwave pulses. In Addition, the output power relative to it under normal drain bias decreases linearly with the increase of drain bias, following the function of PdB=−1.85Vds+5.7. For multi-stage LNA, the observation using optical microscope reveals that the first and second stage HEMT of LNA under zero drain bias are both damaged while only first stage HEMT of LNA under normal bias is damaged with the injection of same large power microwave pulses, which is consistent with simulated output characteristics results.

Parameter estimation of a photovoltaic array using direct search optimization algorithm

This paper presents a parameter estimation technique to determine the photovoltaic (PV) cell parameters from experimental measurements, using the direct search optimization method. A double diode model is considered to represent a photovoltaic (PV) cell, and a Matlab simulation is built to demonstrate the effects of varying various parameters on the output performance. The direct search optimization technique is used to estimate the cell parameters by reshaping the simulated output characteristics to match similar experimental measurements. The procedures that illustrate the implementation of the proposed technique to estimate the PV cell parameters are detailed. The technique is implemented to estimate the parameters of SUNSET PV Module Model PX-170 from experimental measurements. The convergence characteristics of the most sensitive cell parameters are given. The validity of the proposed technique is verified by comparing simulated results obtained using the estimated parameters and their corresponding measurements. The techniques and methodology presented in this paper are of prime importance to power system engineers forming a useful tool for studying power systems including photovoltaic sources.

Theoretical and experimental analyses of the TEA CO2 lasers dynamics by six temperature vibrational-rotational model

A six-temperature dynamic model, modified in terms of vibrational-rotational transitions, has been used to describe the dynamic processes in TEA CO2 lasers. Significant improvement in the predicted laser characteristics was obtained, taking into account the CO2 molecules vibrational-rotational transitions. The coupled differential equations were numerically solved by the fourth order Runge–Kutta method. The simulated output characteristics of the laser have been compared with simple vibrational dynamics model and experimental data due to a homemade TEA CO2 laser. It has been found that the best agreement with experimental results regards to the vibrational-rotational dynamic model.

Analysis of Simulated Output Characteristics of Gas Sensor Based on Graphene Nanoribbon

This work presents simulated output characteristics of gas sensor transistors based on graphene nanoribbon (GNRFET). The device studied in this work is a new generation of gas sensing devices, which are easy to use, ultracompact, ultrasensitive, and highly selective. We will explain how the exposure to the gas changes the conductivity of graphene nanoribbon. The equations of the GNRFET gas sensor model include the Poisson equation in the weak nonlocality approximation with proposed sensing parameters. As we have developed this model as a platform for a gas detection sensor, we will analyze the current-voltage characteristics after exposure of the GNRFET nanosensor device to NH3gas. A sensitivity of nearly 2.7% was indicated in our sensor device after exposure of 1 ppm of NH3. The given results make GNRFET the right candidate for use in gas sensing/measuring appliances. Thus, we will investigate the effect of the channel length on the ON- and OFF-current.

A circuit-based photovoltaic module simulator with shadow and fault settings

The main purpose of this study was to develop a photovoltaic (PV) module simulator. The proposed simulator, using electrical parameters from solar cells, could simulate output characteristics not only during normal operational conditions, but also during conditions of partial shadow and fault conditions. Such a simulator should possess the advantages of low cost, small size and being easily realizable. Experiments have shown that results from a proposed PV simulator of this kind are very close to that from simulation software during partial shadow conditions, and with negligible differences during fault occurrence. Meanwhile, the PV module simulator, as developed, could be used on various types of series–parallel connections to form PV arrays, to conduct experiments on partial shadow and fault events occurring in some of the modules. Such experiments are designed to explore the impact of shadow and fault conditions on the output characteristics of the system as a whole.

Research on Control Strategy of Microgrid Inverter Based on Virtual Synchronous Generator

In view of the conventional droop control method of inverter cannot fully meet the requirements of the microgrid operation,a new control strategy which is based on the traditional control method and combine with synchronous generator model is put forward, also known as VSG control strategy.AVSG model is establish, focusing on the design of the power frequency controller and excitation controller. The role of the rotational inertia and the power allocation problem of two VSGs in parallel networking system are verified through Matlab / Simulink simulation. The results show that, microgrid inverter based onVSG control strategy can simulate output characteristics of synchronous generator well and is conductive to microgrid operation

Comparison of simulation models for the coaxially-gated carbon-nanotube field-effect transistor

Carbon-nanotube field-effect transistors (CNFETs) have received great attention as possible successors to metal-oxide-semiconductor field-effect transistors (MOSFETs) beyond the sub-10 nm era. In this work, numerical simulations were performed on single-walled semiconducting CNFETs using a FETToy simulator and a compact model with or without a smoothing parameter. The discontinuity in the derivative of the surface potential with respect to V GS in the compact model can be remedied by employing a simple smoothing parameter. The simulated output characteristics of CNFETs with a 1.5-nm-thickgate insulator and a 3-nm-diameter nanotube channel exhibited the advantage of using a smoothing parameter. Our results show fairly good matches between the FETToy model and the compact model with a smoothing parameter of less than 5 × 10−4.

Modelling of Carbon Nanotube Field Effect Transistors oriented to SPICE software for A/D circuit design

We present a model of Carbon Nanotube Field Effect Transistors (CNTFETs) directly and easily implementable in simulation SPICE software for electronic circuit design.The model is based on analytical approximations and parameters extracted from quantum mechanical simulations of the device and depending on the nanotube diameter and the oxide capacitance. Comparison of the simulated output and transfer characteristics with those of a numerical model available online and with experimental data shows a relative error less than 5% in both cases.In order to determine the values of CNTFET equivalent circuit elements a new procedure, based on a best-fitting between the measured and simulated values of output device characteristics, has been proposed.To verify the versatility of the proposed model we use it in the SPICE simulator to design some A/D electronic circuits, demonstrating the importance of the quantum capacitance dependence on polarisation voltages and examining the effects of the CNT quantum resistances.

Characterization and Analysis of the Temperature-Dependent on -Resistance in AlGaN/GaN Lateral Field-Effect Rectifiers

The on-resistance and its temperature dependence of the high electron mobility transistor (HEMT)-compatible lateral field-effect rectifier (L-FER) are investigated. Three types of transfer length method (TLM) patterns are utilized to extract the temperature-dependent electrical parameters of the resistance model. The technique presented in this paper delivers a direct and simple methodology for the investigation of the temperature dependence of the on-resistance in the L-FER. The simulated output characteristics of the L-FER are in good agreement with the experimental results.

An Adaptive Body-Bias Generator for Low Voltage CMOS VLSI Circuits

A CMOS body-bias generating circuit has been designed for generating adaptive body-biases for MOSFETs in CMOS circuits for low voltage operation. The circuit compares the frequency of an internal ring oscillator with an external reference clock. When the reference clock is “high,” forward body-bias is generated. When the reference clock is “low,” a reverse body-bias is generated. The forward body bias is limited to no more than 0.4 V to avoid CMOS latchup. The reverse body bias is limited to 0.4 V and is very effective in suppressing the subthreshold current. The frequency adaptive body-bias generator circuit has been implemented in standard 1.5 μm n-well CMOS technology and simulated using SPICE. Excellent agreement is obtained between the simulated output characteristics and the corresponding experimentally measured behavior. It is also demonstrated that up to 90% leakage current in CMOS circuits can be reduced by applying the adaptive bias generator to lower threshold voltage CMOS circuits. The design is simple and can be embedded in low power CMOS designs such as the physical nodes of wireless sensor networks.

Simulation and optimization of GaN-based metal-oxide-semiconductor high-electron-mobility-transistor using field-dependent drift velocity model

Undoped GaN-based metal-oxide-semiconductor high-electron-mobility-transistors (MOS-HEMTs) with atomic-layer-deposited Al2O3 gate dielectrics are fabricated with gate lengths from 1 μm up to 40 μm. With a two-dimensional numerical simulator, we report simulation results of the GaN-based MOS-HEMTs using field-dependent drift velocity model. A developed model, taking into account polarization-induced charges and defect-induced traps at all of the interfaces and process-related trap levels of bulk traps measured from experiments, is built. The simulated output characteristics are in good agreement with reported experimental data. The effect of the high field at the drain-side gate edge and bulk trap density of GaN on the output performance is discussed in detail for the device optimization. AlGaN/GaN/AlN quantum-well (QW) MOS-HEMTs have been proposed and demonstrated based on numerical simulations. The simulation results also link the current collapse with electrons spreading into the bulk, and confirm that a better electron localization can dramatically reduce the current collapse for the QW-MOS-HEMTs. Due to the large band edge discontinuity and effective quantum confinement of the AlGaN/GaN/AlN quantum well, the parasitic conduction in the bulk is completely eliminated.

A comprehensive four parameters I– V model for GaAs MESFET output characteristics

A comparison of nine different nonlinear I– V models for the simulation of submicron GaAs MESFET dc characteristics has been made. Drain-to-source current, I ds as a function of gate-to-source, V gs and drain-to-source, V ds voltages has been simulated and then compared with experimental data. To determine the accuracy of a model, root-mean-square (RMS) errors were calculated. The lowest RMS error was observed for Ahmed model whereas it was highest for Statz model. An ideal Schottky barrier junction free from interface states has been assumed in these models and thus their applications in device simulation are limited. To simulate output characteristics of a GaAs MESFET having finite density of sates at Schottky barrier, Ahmed model has been modified. It has been demonstrated that the proposed model is a comprehensive one and can simulate the device characteristics, with significant improved accuracy, for varying Schottky barrier conditions.

Modeling the impact of light on the performance of polycrystalline thin-film transistors at the sub-threshold region

The impact of the light illumination on the drain current of polycrystalline silicon thin-film transistors (TFT) is studied in this work. The increase of the output current as a result of raised light intensity is modeled, based on measured experimental data for different Vds and Vgs values and transistor sizes W/L. The proposed model has been verified against the measurements and the simulated output characteristics give a good approximation in the sub-threshold region.

Overgrown silicon PBT's: calculations and measurements

The device parameters of overgrown silicon permeable base transistors (PBT's) have been systematically investigated by two dimensional drift diffusion simulations and analytical calculations. Hence some design rules arise for optimizing the high frequency performance of PBT's. The calculations indicate the source-drain distance as the essential PBT parameter, which should be kept below 200 nm in order to expect unity-current-gain frequencies f/sub T/ over 50 GHZ. In addition, PBT's with buried monocrystalline CoSi/sub 2/-gates have been fabricated by high dose cobalt ion implantation through a grid-like mask into MOS-compatible n-type Si(100). Measurements revealed a transconductance of 70 mS/mm and a f/sub T/ value of 6 GHz. The comparison between measured and simulated output characteristics shows good agreement. >

Fix to negative output conductance problem in BSIM2 model (MOSFET)

The long-standing negative output conductance problem observed in the BSIM2 model, which causes convergence problems in circuit simulation, has been studied and resolved. The problem is identified to be related to both parameter extraction methodology and model equations. A redundant boundary condition in the saturation region for the optimization of output characteristics was found. A problematic channel length modulation equation also contributes to the problem. The fix to this problem not only eliminates the negative conductances in the simulated output characteristics of long-channel transistors but also preserves fits to output characteristics of short-channel transistors. The fix, at the same time, speeds up the parameter extraction process by 20% by eliminating five of the model parameters. >