Complete Equivalent Circuit Research Articles

Complete Electrical Equivalent Circuit Based Modeling and Analysis of Permanent Magnet Direct Current (DC) Motors

The modeling and analysis of permanent-magnet DC motor, whose attractiveness has increased with the availability of high-energy rare earth permanent magnet materials such as SmCo and NdFeB, is very important in recent years. The analysis of the established model is very important for researchers and engineers before siteworks. The most important features of the established model are that the equations are simple to obtain, the model can be set up using a simple platform, and ease of model analysis. Generally, for DC motor models, only the armature circuit model is given and only the equations of the mechanical system are given. In the armature circuit model, equations are obtained by switching to the s-domain, and analyzes are made on highly advanced platforms by using these equations. In this study, electrical equivalents of mechanical equations were obtained and both armature circuit and mechanical parameters of a DC motor were expressed as electrical circuit elements. Although the motor model includes mechanical parameters and variables, the whole model is expressed only with electrical elements and variables. Thus, a complete electrical equivalent circuit is proposed for the dynamic model of the permanent-magnet DC motor, in which both the armature and the mechanical part can be modeled as an electrical circuit. With the analyzes, the performance of the permanent magnet DC motor model was examined and it was seen that the system dynamics responses were compatible.

Employing simplified resistance–inductance–capacitance equivalent circuits to analyze and confirm a gallium nitride‐based current linear regulator for laser diode controls

Employing simplified resistance–inductance–capacitance equivalent circuits to analyze and confirm a gallium nitride‐based current linear regulator for laser diode controls

Mathematical model of a frequency pressure transducer based on a resonant tunneling diode

The paper presents the design of pressure sensor with a frequency output signal that is based on the physical processes in a resonant tunnel diode under the action of pressure. The use of devices with negative differential resistance can significantly simplify the design of pressure sensors in the entire radio frequency range. Depending on the operating modes of the sensor, an output signal can be obtained in the form of harmonic oscillations. Pressure sensor characteristics researches based on complete equivalent circuit diagram resonant tunnel diode, which takes into account its capacitive and inductive properties. A mathematical model of the pressure sensor was developed, upon which the analytical dependences of the change in the elements tunnel resonance diode from pressure have been determined, as well as conversion functions and sensor sensitivity. It is shown that the main contribution to changes in the conversion function and sensor sensitivity is made by the change in the negative differential resistance with the change in pressure. This, in turn, results in different readings of the instrument's output frequency. The sensitivity of the sensor varied from 1.15 kHz/Pa·105 to 14.16 kHz/Pa·105 in the pressure range from 50·105 Pa up to 350·105 Pa.

THz Periodic Array Sensor Design

Closed-form relations with equivalent circuits including mutual inductance effects for periodic array structures operating at terahertz (THz) ranges are developed and presented using the network synthesis method. The complete equivalent circuits taking into account of mutual inductances between unit cells and the periodic structures are given. The closed-form relations developed and given for unit cells and periodic arrays have been verified with 3-D electromagnetic (EM) simulator and Advanced Design System (ADS) circuit simulator. Several prototypes including <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$36\times35$ </tex-math></inline-formula> periodic array have been built and measured. It has been confirmed that the closed-form relations developed using the equivalent circuits for the periodic array structures including all the mutual inductance effects agree with the simulation and measurement results from microwave frequencies to THz ranges.

Lightning Surge Analysis for Overhead Lines Considering Corona Effect

Corona discharge characteristics are measured in a corona cage. The difference is found between the q–u curves under double exponential and damped oscillation surges. The behavior of the minor loops is revealed for the q–u curves under positive and negative damped oscillation surges. An extended improvement is made on the traditional approach for modeling of the q–u curves under damped oscillation surges. The extended approach has the capability of describing the complicated trajectory feature of the minor loops. On the basis of the extended approach, an efficient method is proposed for performing lightning surge analysis of overhead lines considering the corona effect. In the proposed method, an overhead line with corona is divided into a certain number of line segments. Each segment is converted into a circuit unit consisting of a non-linear branch and a linear circuit. With these circuit units connected in sequence, a complete equivalent circuit is constructed for the overhead line with corona. The transient responses can be obtained from the solution to the equivalent circuit. Then, the calculated results are compared with the field test results on a test overhead line.

Voltage and frequency control of standalone wind-driven self-excited reluctance generator using switching capacitors

This paper presents a methodology for voltage and frequency (V–f) control of a standalone wind-driven self-excited reluctance generator (WDSERG). The methodology is based on proposing two different compensation configurations using two switching capacitors (short-shunt and long-shunt compensation) for (V–f) control. The dynamic and steady-state performances of the two configurations are discussed under different operating conditions: wind speeds, load currents and power factors. This analysis is done by developing a complete dynamic model of WDSERG including the excitation capacitors and load. Therefore, complete equivalent circuits are proposed. The values of capacitors are controlled by adjusting the duty cycle of H-bridge circuits with PI controllers. To validate the proposed configurations and their dynamic models and equivalent circuits, simulation results for a 1.5-kW standalone WDSERG and experimental results for 0.2 kW reluctance generator driven by a DC motor, emulating the wind turbine, are carried out. The results show a significant enhancement in voltage and frequency regulation with the selected optimal capacitances for each configuration; however, short-shunt compensation is the preferred configuration as it controls the output voltage and frequency with minimum values of capacitances and minimum required duty variation.

RESEARCH ON A MAGNETIC FIELD SENSOR WITH A FREQUENCY OUTPUT SIGNAL BASED ON A TUNNEL-RESONANCE DIODE

Based on the consideration of physical processes in a tunnel-resonant diode under the action of a magnetic field, the construction of an autogenerating magnetic field sensor with a frequency output signal is proposed. The use of devices with negative differential resistance makes it possible to significantly simplify the design of magnetic field sensors in the entire RF frequency range. Depending on the operating modes of the sensor, an output signal can be obtained in the form of harmonic oscillations, as well as in the form of pulse oscillations of a special form.&#x0D; The study of the characteristics of the magnetic field sensor is based on the complete equivalent circuit of the tunnel-resonant diode. The equivalent circuit takes into account both the capacitive and inductive properties of the tunneling resonant diode. The inductive component exists under any operating conditions, as a result of the fact that the current flowing through the device is always lagging behind the voltage that caused it, which corresponds to the inductive response of a tunnel-resonant diode.

A Complete Equivalent Circuit for Linear Induction Motors With Laterally Asymmetric Secondary for Urban Railway Transit

Since the linear induction motor commonly work with a laterally asymmetric secondary as it is applied to pull rail vehicles, this paper presents a complete equivalent circuit model considering the asymmetry to predict thrust, vertical and transversal forces. First, six correction factors are presented to quantify the variations in the air-gap magnetic flux and secondary induced current as the linear induction motor operating with a laterally asymmetric secondary. Second, it develops a circuit model based on the existing T-model for the rotary induction motor and two correction factors for the magnetizing branch, which is used to indicate the electromagnetic variations in the air-gap flux and secondary plate due to the asymmetry. Third, the mathematical expressions for the thrust, vertical and transversal forces are derived by applying the equivalent circuit model. Then, the six correction factors are calculated with a prototype motor, and the results of them are comprehensively analyzed. Finally, the characteristics in the prototype motor are calculated with the mathematical expressions in a range of rated speed, and validated by the experimental measurements carried out on a test rig and line for linear motors.

Operating characteristics of four‐coil magnetic resonant coupling wireless power transfer under different resonant states

SummaryIn wireless power transfer, the transfer efficiency decreases with the increase of the transfer distance. To improve the power transfer performance, the operating characteristics of a conformal coplanar four‐coil magnetic resonant coupling wireless power transfer system are investigated and analyzed under four different resonant states. Based on the complete equivalent circuit model, the transmission coefficient and the input impendence are calculated. The performance of the systems operated under four resonant states is studied and compared. Also, the origin of the difference is specifically analyzed. The simulation results indicate that the wireless power transfer system operated under State 1, the state where the compensated serial capacitance makes the coils work at the frequency of the maximum Q‐factor, shows the most excellent transfer characteristic among the four resonant states. The transmission coefficient can be well maintained above 0.8 within the transfer distance of 30 cm. Experiment has been carried out for validation, and the result indicates that more power can be delivered to the load for the system operated under State 1.

Studying an Electromagnetic Field and Processes in Hysteresis Electromechanical Energy Converters with a Cone Structure

A study is made the distribution of the magnetic field induction during the hysteretic electromechanical conversion of energy by a cone-shaped transducer. The conversion of energy is modeled mathematically. The formation of a complete equivalent circuit and the compilation and solving of a system of vector equations of voltage equilibrium for the corresponding energy converter are considered.

Modeling and validation of a new reconfigurable patch antenna through equivalent lumped circuit‐based design for minimum tuning effort

AbstractThis study presents a modeling of a new reconfigurable patch antenna with equivalent lumped circuit. Instead of intuitive approaches, including structural changes used in the literature, the proposed reconfigurable antenna design is based on minimum tuning effort using only capacitance adjustments. The proposed design resolves impedance mismatch problem, which occurs due to the nature of using several frequencies by only capacitance adjustments rather than physical structure adjustments. Reconfigurable patch antenna for 2.45 GHz (Wi‐Fi), 3.6 GHz (Wi‐max and 5G), 5.4 GHz (WLAN and 5G) was considered for novel design strategy. A complete equivalent circuit model is configured and validated through AWR software. Full wave analysis of the proposed antenna is performed using CST software. A prototype of the proposed antenna is also fabricated on a FR4 substrate with the dimensions of 48.19 x 38.36 x 1.53 mm3 and measured to validate the full wave analysis and circuit theory solution results. It is shown that the equivalent circuit model, full wave analysis, and measurement results are in good agreement.

Experimentally validated model and analytical investigations on power optimization for piezoelectric-based wireless power transfer systems

This article presents a near-field low-frequency wireless power transfer system utilizing a piezoelectric transducer with magnet tip mass as a receiver. The interaction moment between the uniform B field generated by a Helmholtz coil and the magnet is the means to deliver the electrical energy from the transmitter to an electrical load, which is therefore referred to as magneto-mechano-electric effect. This is the first time a complete equivalent circuit model of such a structure is developed and experimentally verified. Based on the lumped model, various aspects of the power optimization problem are thoroughly discussed, providing a comprehensive view of the system and an important premise for further study.

A Complete Small-Signal MOSFET Model and Parameter Extraction Technique for Millimeter Wave Applications

In this paper, we propose a parameter extraction method for a complete MOSFET small signal equivalent circuit model addressing nearly all the parasitic and non-quasi-static (NQS) effects. Extraction and de-embedding of drain/source/gate series resistances and the substrate network are found to be necessary for obtaining the intrinsic elements of the small-signal equivalent circuit. We demonstrate for the first time, a step-by-step procedure for the extraction and de-embedding of the extrinsic model parameters directly from measurements. As a result, a precise intrinsic parameters derivation in the saturation region is presented. Moreover, for the intrinsic small signal equivalent circuit, a gate drain branch is supplemented in parallel to describe parasitic gate-drain coupling under high frequency up to 60 GHz together with the NQS effects. Finally, the presented parameter extraction method is verified by comparing with the corresponding measurement data from the 40-nm RF CMOS process of Shanghai Huali Microelectronics Corporation.

Equivalent circuit model of high power density SiC converter for common-mode conducted emission prediction and analysis

High power density is the primary design consideration for power converters in more electric aircraft (MEA) to meet both space and weight requirements. Therefore, wide bandgap (WBG) semiconductor switching devices, such as SiC, have been chosen to push the switching frequency of the power converter further for size and weight reduction. To meet power quality and conducted emission requirements, a LCL filter is necessary between the converter output and the power grid. With the power switching devices operating at higher frequency, the parasitic effects of various key circuits of the converter cannot be ignored and must be accounted for in the simulation model. This paper describes a complete equivalent circuit model that includes these effects of DC bus-bar, power semiconductor device, gate driver and LCL filter. With the comprehensive model, common-mode (CM) conducted emissions can be predicted and evaluated during the design phase for performance optimization purpose.

Wireless power transfer system with center-clamped magneto-mechano-electric (MME) receiver: model validation and efficiency investigation

This paper presents a complete equivalent circuit model for a wireless power transfer concept utilizing a center-clamped piezoelectric cantilever beam with magnetic tip masses as a receiver. The analytical solution for the power delivered to a load resistance is given as a function of material properties, beam characteristics and external magnetic field strength. The lumped element model is experimentally verified. The efficiency of the system is thoroughly investigated and validated. The essential effect of the coil resistance is highlighted. The analyses show that optimization of transmitter coil size and geometry of the piezoelectric transducer has a significant impact on the transduction factor between the magnetic-mechanical-electrical domains, which greatly improves the transmission efficiency. Finally, the model for evaluating the efficiency is generalized for other similar structures.

A Contactless Dielectric Constant Sensing System Based on a Split-Ring Resonator-Loaded Monopole

In this paper, a low-cost contactless passive sensor is designed and manufactured. The structure consists of a short-circuited printed monopole antenna coupled to two split-ring resonators. The permittivity of the materials under test is characterized within a near-field link between the sensor and a contactless reader. Concretely, the reader has been implemented by using a broadband patch antenna. The sensing principle relies on the reader detection of the notch introduced by the resonators in the power reflected by the sensor. Specifically, when a sample is placed over the sensor, the change in its effective permittivity produces a frequency shift of the notch detected in the reflection coefficient of the reader. A complete equivalent circuit model of the whole system is proposed. Moreover, the results are corroborated through full-wave simulations. Finally, the whole system is manufactured and measured. It is shown that the system can reliably detect the permittivity of the materials placed over the sensor at a distance between the reader and the sensor equal to 9.52 mm.

Complete cell-level lithium-ion electrical ECM model for different chemistries (NMC, LFP, LTO) and temperatures (−5 °C to 45 °C) – Optimized modelling techniques

In this study a complete cell-level electrical equivalent circuit model (ECM) of energy and power lithium-ion cells with 3 different chemistries and multiple temperatures (−5 °C to 45 °C) is developed and validated under different dynamic load profiles. The chemistries under investigation are Nickel Manganese Cobalt 20 Ah (high energy), Lithium Iron Phosphate 14 Ah (high power) and Lithium Titanate Oxide 5 Ah (high power), providing a range of different cell characteristics and capacities. An updated workflow for the development of the ECM model is presented which includes extended versions of previous characterization and parameterization procedures used to populate a 2nd Order Thévenin ECM topology. The model is able to use two types of charge estimations, the extended coulomb counting and the extended Kalman filter techniques. The accuracy of the simulation in all three chemistries is increased through this improved characterization and optimization procedures. The “Initial State of Charge value”, “Capacity Value”, “Internal Resistance value” and the “Open Circuit Voltage” are included inside the complete model and have shown to affect greatly the accuracy of the simulations, specifically when the extended coulomb counting technique is implemented. The State of Health (SoH) level the validation profile was characterize in combination with the total time the simulation is performed have shown to affect also the accuracy of the simulation. The complete developed model is able to be combined with thermal and ageing models of lithium-ion cells. Combining this with the extended database of validated simulations for the different chemistries and temperatures, provides a suitable model to be extended to pack-level models of battery packs.

Design and Optimization of SHF Composite FBAR Resonators.

We propose an apodization technique-based composite thin-film bulk acoustic wave resonator (c-FBAR) design to enable the displacement and strain energy confinement at the central section of the resonator while in operation at the resonance mode. Sinc-shaped AlN on Silicon on Insulator apodized c-FBARs is designed to attain close to 90% energy localization. In this paper, a single crystal silicon as the mechanical layer and an AlN piezoelectric material as the transducer layer of the resonator implemented by InvenSense Inc.'s AlN MEMS-CMOS platform renders an asymmetric feature to the traditional FBAR resonator. The nature of composite thin-film piezoelectric on substrate FBAR resonators in the super high-frequency (SHF) range is studied in detail. Furthermore, a complete deembedding procedure to extract the resonator parameters from the CMOS + MEMS measured data is also explained meticulously. A complete equivalent circuit modeling for c-FBAR operating in the SHF is provided. Measurement data statistics show that sinc c-FBAR features superior electromechanical coupling coefficient ( ) than that of pentagon c-FBAR. As a result, we successfully demonstrate a sinc c-FBAR resonator operating at 3.264 GHz with an electromechanical coupling coefficient of 2.12%, a loaded quality factor ( ) of 790 and an unloaded of 2507.

Modelling solar cell S-shaped I-V characteristics with DC lumped-parameter equivalent circuits a review

This article reviews and appraises the dc lumped-parameter equivalent circuit models that have been proposed so far for representing some types of solar cells that can exhibit under certain circumstances a detrimental S-shaped concave deformation within the energy-producing fourth quadrant of their illuminated I-V characteristics. We first present a very succinct recollection of lumped-parameter equivalent circuits that are commonly used to model conventional solar cells in general. We then chronologically present and discuss lumped-parameter equivalent sub-circuits that, combined with conventional solar cell equivalent circuits, are used to specifically represent the undesired S-shaped behaviour. The mathematically descriptive equations of each complete equivalent circuit are also examined, and closed form solutions for the terminal current and voltage as explicit functions of each other are presented and discussed whenever available. While comparing the most salient features and explaining the practical advantages and disadvantages of such equivalent circuit models, we offer some comments on possible directions for further improvement.

Идентификация математической модели фильтрокомпенсирующего устройства на основе каткона с учетом нелинейной характеристики магнитопровода

The article considers the complete equivalent circuit of a harmonic filtration and power factor correction (HFPFC) device constructed on the basis of a coil capacitor (in the Russian terminology, katkon), a new passive component of electric circuits. The proposed equivalent circuit takes into account the real parameters of the conductors and dielectric, as well as the magnetic core’s weak nonlinearity. An algorithm for identifying the parameters of the HFPFC physical model’s elements is suggested. The algorithm involves an experimentally study of the device’s frequency responses and solution of the system of nonlinear algebraic equations using the iteration method in the MathCAD environment. Application of the proposed algorithm makes it possible to use the minimal admissible number of measurements and measurement instruments, and calculate the sought parameters solely on the basis of amplitude-frequency responses (AFRs) without considering phase-frequency responses. Adequacy of the considered katkon-based HFPFC device model has been demonstrated from a comparison between the experimental and analytically calculated AFRs, and the accuracy of identifying the device parameters is estimated. The absolute and relative errors in the studied frequency band (50 Hz—10 kHz) have been shown to be within the permissible limits.