Equivalent Circuit Parameters Research Articles

An Estimation Method of an Electrical Equivalent Circuit Considering Acoustic Radiation Efficiency for a Multiple Resonant Transducer

The electrical equivalent model of an underwater acoustic transducer must be exactly defined in the operating frequency band to improve the driving efficiency between a sonar transmitter and a transducer. This paper used the PSO (particle swarm optimization) algorithm to estimate electrical equivalent circuit parameters of a transducer that has multiple resonant modes. The proposed method used a new fitness function to minimize the estimation error between the measured impedance of the transducer and the estimated impedance. The difference to the previous method is that the proposed method considered interference effects of the adjacent resonant modes. Additionally, this paper analyzed the effective power and separated the mechanical and acoustical resistance by considering the acoustic radiation efficiency of the transducer. As a result, the proposed method estimated all parameters at the resonance points which are influenced by the adjacent resonant modes.

Numerical simulation of a squirrel cage motor including magnetic wedges and radial vents

This work is a proposal of a finite element model to obtain the electromagnetic performance of a squirrel cage motor considering the magnetic wedges and radial vents. To analyze the electromagnetic performance at the design stage, without the need to build a prototype, the paper proposes a simple two dimensions finite element model, which includes components as magnetic wedges used to hold the windings in the stator slots, radial vents in the core, which are part of motor cooling system, and edge effects to improve the model. The stator and rotor cores are modeled with an equivalent homogeneous permeability, obtained from the combination of the radial air vents of rotor and stator and the magnetic core material. The permeability of magnetic wedges is also considered. Edge effects considered are the end winding leakage inductance, representing the leakage flux in the end coils of the stator, and an equivalent impedance between rotor bars due to conductivity and leakage flux in the rings of the squirrel cage. The results obtained are compared with experimental tests performed in steady state to validate the model. Furthermore, no-load, and blocked-rotor tests are simulated to estimate the equivalent circuit parameters and draw the typical induction motor torque-speed curve, which is compared with the obtained curve by means of Thevenin’s theorem. With this proposed model, the results are close to the ones obtained experimentally. The implementation of a 3D model is complex, and the computational cost can be much higher, compared to the 2D model developed here.

Extrinsic equivalent circuit modeling of InP HEMTs based on full-wave electromagnetic simulation

With the widespread utilization of indium-phosphide-based high-electron-mobility transistors (InP HEMTs) in the millimeter-wave (mmW) band, the distributed and high-frequency parasitic coupling behavior of the device is particularly prominent. We present an InP HEMT extrinsic parasitic equivalent circuit, in which the conductance between the device electrodes and a new gate–drain mutual inductance term L mgd are taken into account for the high-frequency magnetic field coupling between device electrodes. Based on the suggested parasitic equivalent circuit, through HFSS and advanced design system (ADS) co-simulation, the equivalent circuit parameters are directly extracted in the multi-step system. The HFSS simulation prediction, measurement data, and modeled frequency response are compared with each other to verify the feasibility of the extraction method and the accuracy of the equivalent circuit. The proposed model demonstrates the distributed and radio-frequency behavior of the device and solves the problem that the equivalent circuit parameters of the conventional InP HEMTs device are limited by the device model and inaccurate at high frequencies when being extracted.

An analysis of the eddy effect in through-silicon vias based on Cu and CNT bundles: the impact on crosstalk and power

The performance of three-dimensional integrated circuits primarily depends on the filler material used in the through-silicon vias (TSVs). The most widely used filler material is Cu, but it faces severe reliability issues due to the skin effect and problems related to electromigration at high frequencies. Therefore, single- and multiwalled carbon nanotube (SWCNT and MWCNT) bundles have recently emerged as suitable filler materials for TSVs. Additionally, at high frequencies, electromagnetic forces induce eddy currents that adversely affect the overall performance of TSVs. This paper demonstrates for the first time the impact of eddy currents on TSVs based on Cu as well as SWCNT and MWCNT bundles. An accurate RLGC circuit model is proposed by considering the eddy effect at the depletion layer, neighboring TSVs and in the silicon substrate region. The resulting closed-form expressions for the TSV parasitic parameters are verified against previous experimental data obtained at an operating frequency of 2 GHz. Good agreement between the experimental and analytical data for the resistance and inductance is observed, revealing a difference of approximately 8.02% and 4.95%, respectively. The equivalent circuit parameters are modeled at the 7-nm technology node using a three-line driver-via-load setup. For the proposed setup, the crosstalk-induced delay, the peak noise voltage, and the power dissipation are analyzed with and without consideration of the eddy effect. Irrespective of the TSV height, the MWCNT bundle design demonstrates substantially lower crosstalk delay, peak noise, and power dissipation in comparison with the TSVs based on Cu or SWCNT bundles. The overall difference when including the eddy effect is approximately 16.55%, 2.45%, and 0.27% for the crosstalk delay, noise voltage, and power dissipation, respectively. Furthermore, to demonstrate the complexity of the model at smaller technology nodes, a comprehensive study is performed at the 5-nm and 7-nm technology nodes. It is observed that the delay without the eddy effect at the 5-nm technology node is higher on average by 3.4-fold for Cu, whereas for the TSVs based on MWCNT bundles it is only 2.6-fold higher.

Performance Analysis of Variable Reluctance Linear Resolver by Parametric Magnetic Equivalent Circuit in Healthy and Faulty Cases

In this paper, the performance of Variable Reluctance Linear Resolver (VR-L-Resolver) with overlapping and non-overlapping windings is investigated by a novel parametric Magnetic Equivalent Circuit (MEC). The proposed MEC is capable of modeling various VR-L-Resolvers with arbitrary geometry and adjustable accuracy by changing the number of considered flux tubes. This technique is more suitable for modeling, analysis, and optimizing of the mentioned resolvers thanks to its flexibility and shorter processing time compared to the Finite Element Method (FEM). Moreover, it has the potential to model both healthy and faulty conditions by a unique model. Therefore, the resolver with two windings configurations under healthy and faulty cases are analyzed in this paper to study their performance. In faulty case, the inter-turn and asymmetrical air-gap faults are considered, and the position error is calculated for both cases. Finally, the MEC results are validated by 2D-FEM and experimental results to show the effectiveness of the proposed model. In general, applying a novel MEC-based modeling technique for the resolver sensitivity analysis, under mentioned faults and various windings configurations, is the main paper novelty.

Political optimizer based approach for estimating SOFC optimal parameters for static and dynamic models

Great challenges face many researchers in constructing an equivalent circuit for solid oxide fuel cell as the constructed model should converge to the actual one. There is lack of some parameters in the datasheet provided by the manufacturer. This paper proposes a new methodology based on a recent political optimizer to solve the problem of identifying the unknown parameters of fuel cell equivalent circuit. Six parameters are considered as design variables which are E, A, Jo, RΩ, B, and Jmax, the sum of mean squared error between the measured and estimated stack voltages is considered as the fitness function to be minimized. Two scenarios of the fuel cell operation are implemented, the first one is steady-state model and the second one is the transient/dynamic-state based model, both scenarios are analyzed at different operating conditions. In a dynamic-state based model, two load disturbances are applied and the performance of the constructed model is investigated. Moreover, comparison with other reported approaches and programmed algorithms of grey wolf optimizer, Harris hawks optimizer, multi-verse optimizer, antlion optimizer, and marine predators algorithm is presented. Furthermore, the statistical parameters of best, worst, mean, median, variance and standard deviation for each optimizer are calculated. In the steady-state based model, the minimum fitness function is 1.571e-06 obtained via the proposed approach for operation at 1173 K. In dynamic-based model, the best obtained error via the proposed PO is 1.8697. The results confirmed the preference, robustness, and competence of the proposed methodology in estimating the parameters of SOFC equivalent circuit.

Method for QCM Resonator Device Equivalent Circuit Parameter Extraction and Electrode Quality Assessment.

Quartz crystal microbalance (QCM) resonators are used in a wide range of sensors. Current QCM resonators achieve a simultaneous measurement of multiple physical quantities by analyzing lumped-element equivalent parameters, which are obtained via the introduction of external devices. This introduction of external devices will probably increase measurement error. To realize the measurement of multiple physical quantities while eliminating the measurement error caused by external devices, this paper proposes a measurement method for the lumped-element equivalent parameters of QCM resonators without the need for extra external devices. Accordingly, a numerical method for solving nonlinear equations with fewer data points required and a higher accuracy was adopted. A standard crystal resonator parameter extraction experiment is described. The extracted parameters were consistent with the nominal parameters, which confirms the accuracy of this method. Furthermore, six QCM resonator device samples with different electrode diameters and materials were produced and used in the parameter measurement experiment. The linear relationship between the electrode material conductivity and motional resistance R1 is discussed. The ability of this method to characterize the electrode material and to detect the rust status of the electrode is also demonstrated. These abilities support the potential utility of the proposed method for an electrode quality assessment of piezoelectric devices.

A new comprehensive learning marine predator algorithm for extracting the optimal parameters of supercapacitor model

This paper proposes an improved metaheuristic approach of comprehensive learning marine predator algorithm (CLMPA) to identify the optimal parameters of the supercapacitor equivalent circuit. The division of the iteration numbers among the Marine Predators Algorithm phases causes trapping the particles in the local solutions as they did not have adequate trials to discover the search landscape. Therefore, in this paper, the authors used the principle of the comprehensive learning strategy to guarantee to share the best experiences among all the particles with the target of avoiding the immature convergence. The sum squared error between the experimental and estimated voltages is considered as an objective function. Eight parameters to be identified are Ri, Rd, Rl, Rlea, Ci0, Ci1, Cd, and Cl, two SCs are considered in the analysis with values of 470 F and 1500 F. Other optimization approaches of manta ray foraging optimizer (MRFO), water cycle algorithm (WCA), multi-verse optimizer (MVO), vortex search algorithm (VSA), marine predators algorithm (MPA), Archimedes optimization algorithm (AOA), Jellyfish search algorithm (JS), and Runge–Kutta Based Algorithm (RUN) are programmed and compared to the proposed CLMPA. Moreover, some reported works are considered in comparison. The obtained results confirmed the competence and preference of the proposed approach in constructing a reliable equivalent circuit of SC that converges to the real one.

Ultrathin Solar Cells Based on Atomic Layer Deposition of Cubic versus Orthorhombic Tin Monosulfide

Tin monosulfide can be grown in cubic (π-SnS) and orthorhombic (α-SnS) polymorphs by low-temperature atomic layer deposition (ALD). The optical properties of these polymorphs make them attractive for the realization of plasmonic solar cells with ultrathin absorber layers down to 10 nm in thickness. SnS is also an earth-abundant and nontoxic compound semiconductor of high interest for regular thin-film photovoltaics. To better understand the behavior of the two SnS polymorphs in ultrathin solar cell configurations, we here fabricate, characterize, and analyze a range of such devices. ALD is used to grow SnS and form heterojunctions with zinc oxysulfide [Zn(O,S)], acting as a buffer layer with a composition-tunable bandgap. Apart from the roles of the SnS polymorph and Zn(O,S) composition, the effects of the back contact material and thicknesses of buffer and absorber layers are investigated. Devices using π-SnS and pure ZnO buffers yield the highest photocurrents (3.1 mA/cm2) and higher open circuit voltage (159 mV) than similar α-SnS-based devices. Analysis of the equivalent-circuit parameters suggests that interface recombination limits the voltage for these devices. While Zn(O,S) with a higher sulfur content provides chemical passivation of the SnS interface and excessive open circuit voltages above 600 mV, it also exhibits a too high conduction band offset, which hampers current collection. A growth delay during the ALD of Zn(O,S) on SnS initially amplifies the known sulfur–oxygen exchange reaction, such that a sulfur-rich Zn(O,S) region forms next to the SnS interface. This causes a thin ZnS-like barrier to form already for low cycle fractions of the H2S precursor in the ALD super-cycle. Voltage and fill factor trends suggest an optimal SnS absorber layer thickness in the range of 15–35 nm, presenting an opportunity for plasmonic absorption enhancement. Devices with π-SnS show most promise, but interface recombination versus current-blocking is a dilemma for the SnS/Zn(O,S) heterojunction.

Genetic Algorithm‐Based Improvement to Equivalent Circuit Analysis of Experimental Data in Electrochemical Impedance Spectroscopy

AbstractThe paper discusses implementation of a hybrid algorithm for the optimization of equivalent circuit (EQC) parameters in the processing of electrochemical impedance data. Similar to other works, we use the genetic algorithm (GA) to find approximate values of parameters, which are further refined by a complex nonlinear least squares (CNLS) method, e. g. Levenberg‐Marquardt. This removes the important drawback of CNLS: the need to supply optimized starting values that are close to optimal ones. We propose the sequence of GA operations and values of GA parameters. In comparison to other works, our algorithm is designed to simplify connection of its GA part to existing CNLS procedures in electrochemical software packages. The algorithm was tested with datasets generated for both simple and complex EQCs, with and without added noise. No starting values were needed and the allowed ranges for EQC parameter variations were broader than found in usual experimental practice. For GA population as small as 300 individuals and the limit of only 500 GA cycles, more than 85 % of runs were successful, while in many cases the success rate was 100 %, also for smaller populations.

A New Approach to Estimate Activation Energy of Oil-impregnated Pressboard Stressed under Switching Impulse at Different Temperatures

This paper presents an advanced technique for calculating activation energy of oil-impregnated pressboard through dielectric response current measurement under switching impulse voltage at different temperatures. The proposed technique analyzes the measured impulse voltage and current signals to formulate its equivalent circuit at different temperatures. The equivalent circuit parameters are utilized to determine the shifting of ac conductivity curve along frequency axis with variations in temperatures. Based on the shifted ac conductivity curves at different temperatures, the corresponding activation energy of the insulation is estimated. The effectiveness of the proposed technique is investigated through a few laboratory prepared test samples.

A Real-Time Adaptive IGBT Thermal Model Based on an Effective Heat Propagation Path Concept

The information of junction temperature is crucial for the operational management of insulated-gate bipolar transistor (IGBT) modules. In practice, the junction temperature is typically estimated by using an electrothermal model. IGBT modules are subject to various aging processes during operation, some of which, e.g., substrate solder crack, change the thermal impedance of the IGBT module. However, few works in the literature have included the aging effect on the online thermal behavior modeling of IGBT modules. This article proposes an effective heat propagation path (EHPP)-based real-time adaptive thermal model for IGBT modules, where the EHPP is proposed to quantify the impact of substrate solder cracks on the heat propagation inside the IGBT modules. A straightforward relationship between substrate solder crack and the degree of nonuniformity of case temperature distribution is established. This relationship is then used to approximate the EHPP of the IGBT module in different substrate solder health conditions in real time using the measured nonuniformity of case temperature distribution. Based on the change of the EHPP, the parameters of a thermal equivalent circuit (TEC) model, e.g., an improved Cauer-type TEC, are adjusted online and in real time to track the thermal behavior changes of the IGBT modules caused by substrate solder cracks, leading to a real-time substrate-solder-aging-adaptive thermal model. The proposed real-time adaptive thermal model is validated by simulation studies and experimental tests for a commercial IGBT module.

Optimal design of Axial-Flux Induction Motors based on an improved analytical model

This paper presents an improved analytical model for axial-flux induction motors (AFIMs) based on solving the magnetic vector potential equations. The advantage of the proposed approach is its fast simulation time (fractions of a second against minutes/hours in FEA) while maintaining over 95 % accuracy compared to FEA that makes it suitable for an optimization purpose. This method applies a uniform distribution of the current density in the rectangular shaped rotor/stator slots. The equivalent circuit parameters of the studied AFIMs are extracted using the magnetic energy analysis. The proposed model allows the saturation effect in calculation of the motor performance parameters (power factor and efficiency). The accuracy of analytical model is validated using FEA results. A comprehensive design optimization is presented to show its capability for an optimization purpose. The objective functions in this study are maximum efficiency, maximum power factor, maximum efficiency times power factor, minimum mass, minimum price, maximum efficiency over slip, and maximum power factor over slip. The proposed analytical model can be easily used for AFIMs with different number of poles and phases.

Design of miniaturized FSS using equivalent circuit model and multi-objective particle swarm optimization

A method for designing miniaturized frequency selective surface (FSS) using equivalent circuit model (ECM) and multi-objective particle swarm optimization (MOPSO) algorithm is proposed in this paper. In the proposed method, ECM describing the desired frequency response is established, and parameters of the ECM are determined using the MOPSO algorithm. Combining the ECM analysis and the MOPSO algorithm, the requirements of desired frequency response can be converted into the constraints of equivalent circuit parameters, which simplifies the optimization process of FSS design. For verification, a single-layer bandstop-bandpass FSS composed of convoluted elements with the unit cell size of 0.073λ 0 × 0.073λ 0 is designed. Simulation results show that the −15 dB bandwidth is from 2.62 to 2.83 GHz, and the −0.5 dB bandwidth is from 3.84 to 5 GHz. Meanwhile, the resonant frequency is stable at different incident angles (up to 80°) under TE and TM polarization. Finally, the proposed FSS prototype is fabricated and measured. The measured results agree well with the simulated ones.

Low-power threshold gas discharge by enhanced local electric field in electromagnetically-induced-transparency like metamolecules

To realize efficient nonlinear metamaterials, we investigate a method for enhancing the local electric field in a metamolecule composed of two radiatively coupled cut-wire resonators where resonance of the cut-wire resonators and low-group-velocity propagation of an incident electromagnetic wave simultaneously occurs. Numerical analysis shows that the local electric field in the metamolecule can be enhanced by decreasing the electrode size and the gap of the capacitor structure of the cut-wire resonators while keeping the equivalent electrical circuit parameters of the metamolecule constant. We measure and compare the threshold incident power for a gas discharge in a metamolecule fabricated in our previous study and that in a metamolecule with shrunken capacitor structures. The experiment reveals that shrinking the capacitor structure while keeping the resonance frequency of the metamolecule decreases the threshold incident power for a gas discharge and may increase the gas pressure where the threshold incident power is minimum. Further development of this work will enable us to realize efficient nonlinear metamaterials that have atmospheric-pressure gas as a nonlinear element.

Digital Computer Simulation of Induction Machines.(Dept.E)

A digital simulation of an induction machine is described. The simulation is suitable for analyzing the operation for either a motor or generator with different speeds. The induction generator load is represented in the simulation by symmetrical or unsymmetrical R, L circuits. The computer program described in this paper calculates both the transient and steady-state performance of the machine from its equivalent circuit parameters. The effect of the magnitude and direction of the generator shaft speed on its stability is dis cussed. The method of simulation is relatively easy to program and can be solved with a personal digital computer. The example given was applied to study and illustrates the performance of the induction generator under different operating conditions.

Nonintrusive Method for Induction Motor Equivalent Circuit Parameter Estimation using Chicken Swarm Optimization (CSO) Algorithm

This paper presents a nonintrusive method for estimating the parameters of an Induction Motor (IM) without the need for the conventional no-load and locked rotor tests. The method is based on a relatively new swarm-based algorithm called the Chicken Swarm Optimization (CSO). Two different equivalent circuits implementations have been considered for the parameter estimation scheme (one with parallel and the other with series magnetization circuit). The proposed parameter estimation method was validated experimentally on a standard 7.5 kW induction motor and the results were compared to those obtained using the IEEE Std. 112 reduced voltage impedance test method 3. The proposed CSO optimization method gave accurate estimates of the IM equivalent circuit parameters with maximum absolute errors of 5.4618% and 0.9285% for the parallel and series equivalent circuits representations respectively when compared to the IEEE Std. 112 results. However, standard deviation results in terms of the magnetization branch parameters, suggest that the series equivalent circuit model gives more repeatable results when compared to the parallel equivalent circuit.
 Keywords: Induction motor, Chicken Swarm Optimization, parameter estimation, equivalent circuit, objective function

Estimating the optimal parameters of solid oxide fuel cell‐based circuit using parasitism‐predation algorithm

The process of constructing a reliable mathematical model of solid oxide fuel cell (SOFC) is a challenge due to its complex nature. This paper proposes a new methodology incorporated a recent meta-heuristic algorithm named parasitism-predation algorithm (PPA) to estimate the optimal parameters of SOFC equivalent circuit. Two experiments are conducted in this work; the first one comprises four measured datasets for a commercial enhanced cylindrical SOFC manufactured by Siemen Energy. While the second series consists of five measured datasets for a theoretical dynamic SOFC stack with 96 connected cells. The collected datasets are measured at different operating conditions. An excessive comparative study is presented with other optimizers of comprehensive learning particle swarm optimization (CLPSO), improved PSO with difference mean with perturbation (DMP_PSO), heterogeneous CLPSO (HCLPSO), locally informed PSO (LIPS), modified CSO with tri-competitive mechanism (MCSO), opposition-based learning competitive PSO (OBLCPSO), ranking-based biased learning swarm optimizer (RBLSO), competitive swarm optimizer (CSO), hybrid Jaya with DE (JayaDE), and social learning PSO (SLPSO). Furthermore, statistical analyses of the ranking tests, multiple sign tests, Friedman tests, and ANOVA are performed. The obtained results confirmed the proposed PPA's competence in constructing a reliable model of SOFC as it provides the least mean square error (MSE) between the measured and estimated characteristics of 2.164e−6 in the first series of experiments at 1073 K, in contrast, the most peer (CLPSO) provides 5.57e−6. Similarly, in the second series of experiments, PPA achieves lease MSE of 7.17e−2 at 973 K; meanwhile, the most peer (CLPSO) attains 5.44e−1.

Modeling and analysis of a multi-segmented linear permanent-magnet synchronous machine using a parametric magnetic equivalent circuit

Modeling and analysis of a multi-segmented linear permanent-magnet synchronous machine using a parametric magnetic equivalent circuit

An analytic method for parameter extraction of InP HBTs small-signal model

PurposeHigh-speed Indium Phosphide (InP) HBTs have been widely used to design high-speed analog, digital and mixed-signal integrated circuits. The purpose of this study is to propose a new parameter extraction procedure for determining an improved T-topology small-signal equivalent circuit of InP heterojunction bipolar transistors (HBTs).Design/methodology/approachThe alternating current crowding effect is considered through adding the intrinsic base capacitance in the small-signal equivalent circuit. All of the circuit parameters are extracted directly without using any approximation.FindingsThe extraction technique is more easily understood and clearer than other extraction methods, as the equations are derived from the S-parameters by peeling peripheral elements from small-signal models to get reduced ones and extracting each equivalent-circuit parameter using each equation.Originality/valueTo validate the presented parameter extraction technology, an n-p-n emitter-up InP HBT was analyzed adopting the method. Excellent agreement between measured and modeled S-parameters is obtained up to 40 GHz.