Equivalent Circuit Parameters Research Articles

Modeling of solar batteries operating modes

For the solar power engineering development it is essential to determine the photovoltaic plant energy indicators by modeling the solar batteries operating modes. To obtain an adequate solar battery model, we need to determine its main parameters on the basis of an equivalent electric circuit. Modeling the solar battery operating mode, it is necessary to take into account the influence of its heating temperature. We propose a combined research algorithm in MS Excel with the installed add-on “Search for a solution” for modeling of solar battery operating mode. We have given the results of modeling the solar battery operating mode where the calculated solar battery maximum power including its heating, satisfactory matches with the experimental data. The research shows that excluding the solar battery heating, the maximum power value and, accordingly, its efficiency are overestimated in comparison with the experimental data. Moreover, the results of modeling excluding its heating do not provide the required accuracy and the modeling mistakes are more than 30% especially at relatively high values of solar radiation. The given model allows to determine the equivalent circuit parameters and determine the solar battery maximum power depending on the considered factors of its heating temperature and the incoming solar energy.

Loss Characterization of Giant Magnetostrictive Material Under Compressive Stress

The properties of giant magnetostrictive material (GMM) are very sensitive to external compressive stress. Knowledge of these key properties is of essential importance in practical applications such as high-power underwater transducers. Although the parameters of GMM have been extensively studied, characterization and analysis of magnetic, elastic, and piezoelectric losses under different compressive stresses are rarely reported due to the difficulty in experimentally realizing the ideal mechanical free or clamped boundary conditions. In this study, we designed a longitudinal transducer for complex parameters characterization of GMM. We successfully characterize the key three losses in GMM using a multi-degree-of-freedom (MDOF) lumped parameter equivalent circuit model (LECM), meticulously incorporating the surface contact damping, stiffness, and structural losses. MDOF LECM provides a novel idea for loss characterization of GMM under compressive stress. In contrast to prior-art parameters characterization based on the distributed parameter equivalent circuit model (DECM), the proposed characterization based on MDOF LECM shows apparent superiority in terms of global sensitivity. The intensive losses of GMM for ten-time characterizations show high stability and are all positive. Statistical analysis of intensive losses’ dependency on the compressive stress is performed. A longitudinal transducer is designed for experimental verification. Finally, 95% prediction and confidence intervals for the variation trend of the intensive losses in relationship with compressive stress are obtained.

State of Energy Estimation for Lithium-Ion Battery Pack via Prediction in Electric Vehicle Applications

Accurate state of energy (SOE) estimation of the battery pack is very important for the electric vehicle's driving range estimation, which is still a very challenging problem under actual vehicle application conditions at present. This paper proposes a method for estimating the SOE of the battery pack based on prediction, taking into account the future voltage and temperature changes of the battery pack. Firstly, a novel definition of the battery pack SOE is proposed, which considers the inconsistency of the battery pack. Secondly, the thermo-electric lumped parameter equivalent circuit model of a single cell in the battery pack is applied. The electrical parameters are identified using the forgetting factor recursive least-squares algorithm, and the extended Kalman filter is used to estimate the SOC of each cell. Finally, the future current, voltage and temperature response of the cell in the battery pack are accurately predicted and iterative calculations are performed to get SOE under the condition that the future output power of the battery pack is predicted by the Markov chain model method. The effectiveness of the proposed method is verified under dynamic conditions at different temperatures. The results show that the above method has high precision and good robustness, and can meet the needs of actual vehicle applications.

Estimation of Induction Motor Equivalent Circuit Parameters from Manufacturer’s Datasheet by Particle Swarm Optimization Algorithm for Variable Frequency Drives

Estimation of Induction Motor Equivalent Circuit Parameters from Manufacturer’s Datasheet by Particle Swarm Optimization Algorithm for Variable Frequency Drives

Lumped-Parameter Modeling and Performance Analysis of Fluid-Backed Piezoceramic Flexural Disc Acoustic Sensors

two-port lumped-parameter equivalent circuit model is presented to analyze the electroacoustic characteristics of piezoelectric flexural-mode acoustic sensors with fluid backing. The circuit parameters are determined from the measured electrical admittance spectra in water. Expressions for frequency-dependent receiving sensitivity are derived in terms of the equivalent circuit parameters under two extreme boundary conditions, namely, clamped and simply supported edges. The effect of geometric parameters of the composite flexural discs on the acoustic performance is analyzed. The model is validated by constructing flexural disc hydrophones of several dimensions and configurations, in which the overall thickness is much smaller than the radius. The model results agree well with the experimental data, validating the model. It is found that the receiving sensitivity of practical sensors lie in between clamped edge and simply-supported edge conditions which are the theoretical lower and upper bounds, respectively. Among all the sensors studied, the sensor with the lowest radius ratio (Rp/Rs) has the highest measured receiving sensitivity of -173 dB (ref. 1V/μPa) at low frequencies and -150 dB (ref. 1V/μPa) at resonance. The self-noise characteristics of these sensors are also analyzed with reference to underwater applications. The largest sensor has the highest Figure-of-Merit (FoM) with the measured M2C value of 743 × 10-28 V2F/μPa2, which is about three orders of magnitude higher than typical sensors. Piezoelectric sensors with high FoM is required to design acoustic systems with high Signal-to-Noise Ratio (SNR) with enhanced acoustic receiver characteristics.

FE-Aided Synchronization Analysis of Line-Start Synchronous Reluctance Motors

Since line-start synchronous permanent magnet motors (LSPMs) entered the market, they have attracted research interest toward counterpart induction motors of low power-ratings. This paper reports an investigation of line-start synchronous reluctance motors (LS-SynRMs). LS-SynRMs has not been investigated as much as LSPMs have. A motor needs to maximize rotor saliency to achieve high efficiency and a high power-factor. This results in complicated rotor geometry because the rotor cage and multiple flux barriers share the same rotor space. This paper provides an approximate method based on steady state torque analysis by which to estimate the critical inertia of a LS-SynRM. A finite element analysis (FEA)-aided analytical approach to the approximation of steady state torque is proposed to replace the more typical approach based on equivalent circuit parameters. The critical inertia resulting from the proposed method is compared to the results obtained using the FEA.

Estimation of the Equivalent Circuit Parameters of Induction Motors by Laboratory Test

The determination of equivalent circuit parameters for AC induction motors represents an important task in an electrical machine laboratory. Frequently used open-circuit and short current tests answer these requirements. However, the results have a low accuracy. This becomes especially obvious when the equivalent circuit is applied for the motor current and power prediction. The main obstacles in this circumstance lie in the difficulty of providing a pristine open-circuit test, the lack of which causes errors in parameter estimation. A much more accurate approach can be carried out with a test including several output points with measurements of the motor torque, velocity, current, and power magnitudes. Nevertheless, a relatively simple and accurate method to ensure determining parameters for such tests does not exist. This article tries to provide such a method by an approach based on Kloss’s simplified equation and the Thevenin theorem. The significant novelty of the method is the specially selected synergetic interaction between the analytical and numerical approaches, which give a relatively simple algorithm with a good accuracy and a convergence of the parameters’ estimation.

Analysis of underwater plasma discharge based on equivalent circuit parameters

The control of discharge mode and the optimization of energy efficiency are of particular concern as the significant impact on the application of the underwater plasma discharge system. In this paper, the RLC parameters of each part of the underwater discharge system are investigated, and the equivalent circuit is obtained. Typical waveforms of current and voltage for different underwater discharge modes are displayed. The correlation between the equivalent RLC parameters of the discharge system and the discharge modes and energy is illustrated. The equivalent circuit of the underwater plasma discharge system is utilized to analyze the effects of the power source, electrode, and liquid dielectric parameters. The influences of these parameters can be identical to the impacts on the RLC parameters of the underwater discharge system equivalent circuit simultaneously, and then, the effects on the discharge modes and energy can be better understood. It can be concluded that the relative relationship of system equivalent RLC parameters determines the discharge mode, and the impedance matching between the discharge channel and the external circuit determines the discharge energy.

Accelerating Time–Current Curve Computation of Induction Motor from Manufacturer Data

Accelerating time–current (ATC) curves of induction motors are normally used for setting, selecting, and coordinating their overcurrent protective devices against heating. Conventionally, the ATC curves can be computed using commercial software tools via a dynamic simulation. This approach always needs a completed set of motor circuit-model parameters, which are typically unavailable to users. To eliminate this problem, this article addresses a direct approach to calculate the ATC curves from commonly available manufacturer data sheets of motors without using the sophisticated simulation tool. Mathematical models of motor’s torque and current curves, taking a nonlinear deep-bar effect into account, are proposed for the ATC determination. The computed torque and current profiles are validated by comparison with those generated from the Matlab simulation tool, published equivalent-circuit parameters, and field measurements. An accuracy of the obtained ATC curves is also assessed against those of the dynamic simulations. The satisfactory results are entirely obtained.

Challenges in the Electromagnetic Design of Multiphase Machines: Winding and Equivalent Circuit Parameters

The usage of multiphase electrical drives expands the operation possibilities of electrical machines and opens new directions of research on inverter-fed electrical machines. With an increasing number of phases, the standard approach of the electromagnetic design of machines has to be generalized to m-phase systems, which is not usually respected in the literature focused on electric machine design, and it is rarely published. This paper summarizes the specific problems linked with the design of machines with different numbers of phases, focusing on the winding design and the calculation of equivalent circuit parameters. In addition to the direct effect of different numbers of phases, the impact of injecting higher order time harmonic components on the electromagnetic design of electric machines is analyzed. The obtained analytical results are verified by the measurement of a nine-phase experimental induction motor.

Optimized Design of a Sonar Transmitter for the High-Power Control of Multichannel Acoustic Transducers

For driving multichannel underwater acoustic transducers, the integrated design of the transmitter based on the analysis of the widely distributed impedance should be considered. Previous studies focused on either the matching circuit or the fast resonant tracking control. This paper proposes the design and control methods of a sonar transmitter based on the analysis of the impedance distribution. For the transmitter design, the optimization method based on the particle swarm optimization (PSO) algorithm is proposed for estimating the equivalent and matching circuit parameters. The equivalent circuits of the transducer are more precisely designed by using the measured data in both air and water. The fitness function proposed in the matching includes special functions, such as the limitation and parasitic inductances. A comparison of the experimental and simulation results shows that the optimized matching design improved the power factor, and was similar to the experimental result. For the transmitter control, the constant power and voltage control (CPVC) and instant voltage and current control (IVCC) methods are proposed for the variable impedance load. The impedance variation range affects the rated power and rated voltage of the transmitter, and the rating range determines the initial modulation index (MI) of the pulse-width modulation (PWM) control. To verify the control method, an experimental setup including the multichannel acoustic transducers was established. As a result, the constant power and constant voltage were verified with the proposed control, and the instant voltage and current control also worked in the event that the instant voltage or current exceed their threshold values.

Changes in the immitance spectra of the cement paste in the initial period of hardening

The paper analyzes changes in the impedance and admittance spectra of the cement slurry during hardening. The spectra were measured in the frequency range from 20 Hz to 2 MHz on a precision RLC meter Agilent E4890A using a homemade capacitor measuring cell. The studies in order to establish the optimal equivalent electrical circuits describing the transformation of the electrophysical properties of the cement slurry and interface phenomena in the near-electrode layer of the measuring cell from the time of hardening were carried out. The sensitivity of the parameters of equivalent circuits to different stages of cement slurry hardening has been established.

Equivalent Circuit Modeling of an Induction Reaction Sphere for Microspacecraft Attitude Control

A reaction sphere (RS) is a novel and promising actuator for microspacecraft attitude control systems (ACSs). However, the detection of the motor status, such as the rotating speed of the spherical rotor, is a difficult task. The equivalent circuit can be used to predict the motor status. This article presents an improved multi-layer transfer-matrix method for the equivalent circuit parameters’ calculation. Results compared with a finite element analysis (FEA) show that the proposed analytical model achieves an acceptable accuracy within the operating speed range. Meanwhile, its computation time is 0.072 s, on average, which is only 0.0003% of the FEA.

A Packaged THz Shunt RF MEMS Switch With Low Insertion Loss

This paper demonstrates a packaged THz shunt capacitor micro-electromechanical systems (MEMS) switch with low insertion loss. In-line shunt switch is used to achieve a low loss in THz band, which is realized by reducing the equivalent parallel inductance of switch. The equivalent circuit of the switch is analyzed systematically, the equivalent resistance is obtained based on the skin effect of high frequency current on the conductor and the current density distribution characteristics of the conductor cross-section. The equivalent capacitance is obtained by using &#x201C;double microstrip&#x201D; characteristic impedance calculation method, and the correction factor (<inline-formula> <tex-math notation="LaTeX">$\Delta$ </tex-math></inline-formula>) is introduced to calculate the equivalent inductance accurately. By optimizing equivalent circuit parameters and switch sizes, the structure of MEMS switch with low loss and high isolation characteristics are achieved. The switch is packaged by rectangular waveguide and achieved a low insertion loss. The comparison between the switch simulation results and the equivalent circuit simulation results verify that the parameter extraction method and circuit analysis are correct. The packaged MEMS switch is measured, and the results are in an acceptable agreement with simulation, the switch is actuated under voltage of &#x007E;30V. The measured result has achieved a low insertion loss with less than &#x003C; 2dB from 220 to 280GHz, and isolation with &#x007E;16 dB from 240GHz to 320GHz in the &#x201C;down&#x201D; state.

An improved electrochemical‐based model to estimate battery equivalent circuit parameters for pulsed discharge scenarios

AbstractLithium‐ion batteries (LIBs) power almost all consumer electronics products these days. High‐energy density and low cost are some of the reasons behind LIBs being used to electrify all modes of transportation. Battery equivalent circuit models enable estimation of the state of battery energy and power. These models also assist in the capturing dynamic and transient operation of electric vehicles (EVs). Researchers have used lumped equivalent circuit models in the past which fail to capture the transient variation of battery capacity during pulsed charging scenarios. In this article, we approach the estimation of battery equivalent circuit parameters from an electrochemical model‐based approach. This is the first research work to employ the single particle model that considers the electrolyte behavior to derive battery equivalent circuit parameters. We evaluate this approach using three different batteries of varying cell capacities. This technique not only improves the accuracy of these models but enables a complete understanding of the transient load operation of these batteries.

Development of a tissue discrimination electrode embedded surgical needle using vibro-tactile feedback derived from electric impedance spectroscopy.

Some tumours may not be detected by ultrasound during biopsy, but recent evidence has shown that different tissues can be discerned by electric impedance. This paper explores the application of vibrotactile feedback in an electrode embedded needle to help classify tissue during fine-needle aspiration biopsy from bioimpedance measurements. The process uses electric impedance spectroscopy from 10 Hz to 349 kHz to fit the double-dispersion Cole model through the Newton-Raphson algorithm. A Naive Bayes classifier is then used on the equivalent circuit parameters to estimate the tissue at the needle tip. The method is validated through a series of experiments and user trials. The results show that the vibrotactile feedback is able to help the operator in determining the tissue the needle is in, suggesting that this may prove to be a useful supplement to the standard procedure used today. Graphical Abstract This paper explores the application of vibrotactile feedback for an electrode embedded needle to help classify tissue from electric impedance measurements. The data is fit to an equivalent circuit using Newton- Raphon's method. A Naive Bayes classifier is trained and later used in an experiment to estimate the tissue at the needle tip and provide an assigned vibrotacticle feedback to the user.

A Deterioration Diagnosis Circuit of a Lithium-Ion Battery Using Microcomputer Implementing Z-Transform Convolution

The deterioration of lithium-ion batteries has been detected by an increase in the battery impedance by means of an alternating current method or a battery capacity test. These methods require an interruption of the operation because the battery has to be removed. A method estimating equivalent circuit parameters of a lithium-ion battery during operation is proposed in this article. The increase in the internal impedance has a close relation to the deterioration of the battery. The circuit is expressed by a resister and an RC parallel circuit connected in series. The parameters can be estimated by applying a convolution technique to the voltage and current fluctuation of the battery during operation. A diagnosis circuit using a microcomputer is developed using a simple algorithm employing z-transformation in the parameter estimation. The estimated parameters depend on its state of charge (SOC) and ambient temperature. The SOC dependency is solved by estimating timing, and the temperature dependency is corrected by a function derived in this article. The deterioration diagnosis of the battery can be applied to a solar power generation system, and the feasibility is discussed in this article.

Bayesian Estimation of Equivalent Circuit Parameters of Photovoltaic Cell with S‐Shaped Current–Voltage Characteristic

An S‐shaped current–voltage characteristic is frequently observed in a photovoltaic cell using emerging materials such as organic semiconductors and organic–inorganic perovskite materials. The opposed two‐diode equivalent circuit model, whose explicit analytical solution is known, can reproduce the S‐shaped characteristic. However, since the number of parameters is as high as eight, it is not easy to extract the equivalent circuit parameters from experimental data by curve fitting. Herein, the Bayesian estimation in extracting the equivalent circuit parameters of the opposed two‐diode model is demonstrated. Unlike the traditional nonlinear least‐squares method, the Bayesian estimation practically does not require any tuning of the initial values and gives the information on the error of the estimates.

HTS–SLIM design based on Bayesian multi–level, multi–objective optimization and Gaussian process models

The performance of the Linear Induction Motor (LIM) is based on the linear force in the moving direction. However, due to the length limitation of LIMs, the end–effects as the barrier force decrease their performance. On the other hand, the primary width is lower than the secondary that causes the non–homolographic distribution of the air gap flux density. These effects result in the reduction of output thrust. In recent decades, the windings are made of High–Temperature Superconducting (HTS) tapes to reduce their power losses and total weight. However, due to their magnetic losses, the HTS–LIMs generally are low efficiency and need an optimal design. In this paper, an optimal design of an HTS Single–sided LIM (SLIM) is conducted by analyzing the proposed equivalent circuit parameters. Also, the output variables of the HTS–SLIM are calculated using the proposed analysis, which is different from the conventional SLIMs. The bayesian optimization algorithm (BOA) is used to optimize the objective functions, which consists of the efficiency, power factor, braking force due to end effects, and AC losses. Moreover, various models of the Gaussian Process (GP) are employed for modeling the objective functions at each step of the BOA process. Since the problem construction is multi–objective, the optimization algorithm is modified as the Multi–Objective BOA (MO–BOA) to optimize the mentioned objectives simultaneously. The problem is also considered as a multi–level problem owing to the various levels based on the sensitive analysis of HTS–SLIM parameters. For increasing the results accuracy, different effects of SLIM such as end-, skin-, and edge- effects are studied in the analytical model. The results of different models of GP and other methods are compared to show the robustness of the proposed method. Also, a 3D model of the motor is built and analyzed with the Finite Element Method (FEM) to verify the results of the analytical approach. The results for both FEM and analytical method show that the proposed structure has high performance and could be applied in practical applications.

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.