RLC Parameters Research Articles

Hybrid Analytical-FEM Approach for Power Transformer Transient Analysis

The paper describes a high-frequency model for transient calculation in transformer windings with segmentation on a turn level. The windings are represented by lumped RLC parameters given by the analytical approach, whereas the model is solved in the time domain. The accuracy of the analytical calculation is improved with correction factors obtained with a set of numerical calculations. The presented model is verified by measurements on the example of power transformer disc winding.

Enhanced Three-Phase AC Common-Mode Filter With Optimized Damping Network for VFDs

This paper presents a highly integrated three-phase AC common-mode (CM) filter with optimized damping network for low voltage, high current motor drive applications. Simplified reduced order models and design guidelines for tuning of RLC parameters are proposed. A single turn AC-CM inductor can be realized using the proposed circuit and design technique, due to lower magnetizing inductance requirement. The RC network is found to provide 50% higher attenuation to peak CM currents compared to a conventional AC inductor alone. At the same time, the peak-volt-second across the CM inductor can be reduced, which is critical for weight sensitive applications. A trade-off between AC-CM inductance and damping resistor losses is evaluated to extract the desired optimal RLC parameters of the AC filter. The proposed circuit is designed and verified with high power <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SiC</i> -based Three Level T-type inverter.

Application of circuit analog optimization method in fast optimization of dynamically tunable terahertz metamaterial sensor

The simulation design of terahertz metamaterial sensors with dynamically tunable parameters typically relies on manual parameter tuning for structural optimization. However, this method is often prone to subjective factors and suffer from issues such as frequent reconstruction of simulations, high computational costs, long processing times, and suboptimal optimization results. In this paper, we propose a circuit analog optimization method (CAOM), which constructs equivalent RLC parameters to achieve a highly fitted terahertz transmission spectrum frequency obtained from CST full-wave numerical simulation. To validate the effectiveness of the proposed model, we use a typical periodic structure unit, a double-nested split ring resonator (DSRR) terahertz metamaterial sensor, as the simulation object. Both the inner and outer open resonant rings of the sensor are made of graphene, as a result, the opening size and Fermi level of the resonant rings are dynamically tunable. The results of the validation demonstrate that the adjustments of the sensor parameters can be effectively mapped by the changes of the equivalent RLC parameters. And the proposed equivalent circuit model has parameter substitutability in the simulation modeling of split ring resonator type sensors. The proposed equivalent circuit model exhibits parameter substitution in the simulation modeling of open resonant ring-type sensors. To achieve optimal sensing performance for the electromagnetically induced transparency (EIT)-like resonant peak (with a resonant frequency of f 2) of the sensor under constrained conditions, we introduce the genetic algorithm (GA) into the equivalent circuit model to enable fast optimization of the opening sizes of the inner and outer resonant rings, as well as the Fermi level of the sensor. Moreover, the accuracy of the optimization results is verified by CST simulations. Finally, the optimization results show that the optimal FOM of the EIT-like resonant peak within the given parameter range is 0.712, which is greater than that of any randomly combined parameters. This numerical result demonstrates the effectiveness of the proposed CAOM. The proposed model and optimization method have potentials to inspire further research in device design, performance optimization, theoretical modeling, etc.

Case study on transformer models for calculation of high frequency transmitted overvoltages

Events such as lightning, switching of vacuum circuit breaker or switching operations in gas insulated substation (GIS) generate high frequency overvoltages. An equipment in a transmission or a distribution system has to be protected against such phenomena. Unfortunately, the traditional transformer models available in Electromagnetic transient simulations program (EMTP-like) software packages are not capable of representing transformer behavior in a transient state, which includes high frequencies. Moreover, high frequency transformer models are often too complex or require confidential information on transformer geometry. However, in the design stage of insulation coordination it is particularly important to accurately calculate transmitted overvoltages through transformers. In the scope of this paper two different transformer models for high frequency, are developed in an EMTP-type software program. The first model named “Black box” derives solely from the values measured on the transformer terminals and does not require any knowledge of the transformer inner geometry. The second model named “Grey box”, is based on a lumped RLC parameters network, whose values are derived from the simple geometry of the transformer window and from the nameplate data. Furthermore, the models’ capabilities to characterize a transformer at high frequencies are analyzed. The case study is done on a distribution transformer which is to be located inside a power plant. The transmitted overvoltages calculated with the models in the EMTP-type software program are compared with measurements.

Preliminary Analysis of Burn Degree Using Non-invasive Microwave Spiral Resonator Sensor for Clinical Applications.

The European “Senseburn” project aims to develop a smart, portable, non-invasive microwave early effective diagnostic tool to assess the depth(d) and degree of burn. The objective of the work is to design and develop a convenient non-invasive microwave sensor for the analysis of the burn degree on burnt human skin. The flexible and biocompatible microwave sensor is developed using a magnetically coupled loop probe with a spiral resonator (SR). The sensor is realized with precise knowledge of the lumped element characteristics (resistor (R), an inductor (L), and a capacitor (C) RLC parameters). The estimated electrical equivalent circuit technique relies on a rigorous method enabling a comprehensive characterization of the sensor (loop probe and SR). The microwave resonator sensor with high quality factor (Q) is simulated using a CST studio suite, AWR microwave office, and fabricated on the RO 3003 substrate with a standard thickness of 0.13 mm. The sensor is prepared based on the change in dielectric property variation in the burnt skin. The sensor can detect a range of permittivity variations (εr 3–38). The sensor is showing a good response in changing resonance frequency between 1.5 and 1.71 GHz for (εr 3 to 38). The sensor is encapsulated with PDMS for the biocompatible property. The dimension of the sensor element is length (L) = 39 mm, width (W) = 34 mm, and thickness (T) = 1.4 mm. The software algorithm is prepared to automate the process of burn analysis. The proposed electromagnetic (EM) resonator based sensor provides a non-invasive technique to assess burn degree by monitoring the changes in resonance frequency. Most of the results are based on numerical simulation. We propose the unique circuit set up and the sensor device based on the information generated from the simulation in this article. The clinical validation of the sensor will be in our future work, where we will understand closely the practical functioning of the sensor based on burn degrees. The senseburn system is designed to support doctors to gather vital info of the injuries wirelessly and hence provide efficient treatment for burn victims, thus saving lives.

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.

Study on circuit modeling of stretchable serpentine interconnects

AbstractA 2π equivalent circuit model of serpentine interconnect fabricated by transfer printing technology is proposed considering the stretching deformation of the interconnect. The S parameters are measured, and the RLC parameters are extracted by quasi‐linearization method at various elongations. A V‐shaped model is built to illustrate the change of Lc increasing by 9.7% due to elongation. A branch of Rf and Lf in parallel is utilized to model the impact of high‐frequency effects, Rf decreases by 56.7%, and Lf remains ~0.65 nH. A branch of Rsub and Csub characterizing the electrical loss of substrate increases due to substrate thinning with elongation, Rsub increases by 87.1%, and Csub remains 100 fF. S parameters are measured and compared to verify the accuracy of the model and study the effect of elongation on the transmission characteristics; it is found that the amplitude at S11 minimum decreases from −7 to −10 dB during stretching, and the corresponding frequency points also decrease.

Extracting RLC Parasitics From a Flexible Electronic Hybrid Assembly Using On-Chip ESD Protection Circuits

The presence of RLC line parasitics in a flexible hybrid electronic assembly can lead to signal integrity issues, and their progression over time can lead to catastrophic failures. A technique for extracting the RLC line parasitics from a flexible hybrid electronics assembly is presented. The proposed extraction method exploits the on-chip ESD protection circuits of an IC chip to extract the parasitics of the printed conductors bonded to the chip. This is performed through a single test access port, i.e., two test points. While the parasitics LC are extractable through one-port reflection-based techniques such as time domain reflectometry; the parasitic R requires a two-port measurement such as Kelvin test, which is extremely difficult to perform for printed conductors bonded to small surface-mount IC package devices. The accuracy of the extracted RLC parameters with the proposed method are verified with a prototype developed on a rigid FR4 substrate. Subsequently, the proposed technique is utilized to track the variation of the RLC parasitics for prototypes developed on Kapton Polyimide substrate subjected to different forms of bending.

Scattering Evaluation of Equivalent Surface Impedances of Acoustic Metamaterials in Large FDTD Volumes Using RLC Circuit Modelling

Most simulations involving metamaterials often require complex physics to be solved through refined meshing grids. However, it can prove challenging to simulate the effect of local physical conditions created by said metamaterials into much wider computing sceneries due to the increased meshing load. We thus present in this work a framework for simulating complex structures with detailed geometries, such as metamaterials, into large Finite-Difference Time-Domain (FDTD) computing environments by reducing them to their equivalent surface impedance represented by a parallel-series RLC circuit. This reduction helps to simplify the physics involved as well as drastically reducing the meshing load of the model and the implicit calculation time. Here, an emphasis is made on scattering comparisons between an acoustic metamaterial and its equivalent surface impedance through analytical and numerical methods. Additionally, the problem of fitting RLC parameters to complex impedance data obtained from transfer matrix models is herein solved using a novel approach based on zero crossings of admittance phase derivatives. Despite the simplification process, the proposed framework achieves good overall results with respect to the original acoustic scatterer while ensuring relatively short simulation times over a vast range of frequencies.

Time-Varying Resistance Optimization for the Resistive Type Superconducting Fault Current Limiter Applied in VSC-HVDC System

When short-circuit fault occurs in a voltage source converter–based high-voltage direct current (VSC-HVDC) transmission system, the fault current curve is much more complex than conventional AC power grid. The high-voltage DC circuit breaker with large cut-off capacity is rather expensive; thus, some current limiting methods are proposed to limit the fault current. The superconducting fault current limiter (SFCL) is one of the promising devices for both AC and DC short-circuit current limiting application. The optimization criterion for SFCL applied in VSC-HVDC system is presented, and a four terminal VSC-HVDC system is adopted as an example. The short-circuit fault could be divided into condenser discharge and AC system feeding process, and the fault current curve is related to the time-varying RLC parameters of the grid. The thermal and resistance characteristics of the SFCL are analyzed, and the optimization method of the current limiting impedance and thermal characteristics of the SFCL is developed based on the time-varying fault current. Finally, the design of a 160-kV SFCL was completed based on the proposed method.

An integrated lumped-parameter model of the cardiovascular system for the simulation of acute ischemic stroke: description of instantaneous changes in hemodynamics.

Acute Ischemic Stroke (AIS) is defined as the acute condition of occlusion of a cerebral artery and is often caused by a Hypertensive Condition (HC). Due to its sudden occurrence, AIS is not observable the right moment it occurs, thus information about instantaneous changes in hemodynamics is limited. This study aimed to propose an integrated Lumped Parameter (LP) model of the cardiovascular system to simulate an AIS and describe instantaneous changes in hemodynamics. In the integrated LP model of the cardiovascular system, heart chambers have been modelled with elastance systems with controlled pressure inputs; heart valves have been modelled with static open/closed pressure-controlled valves; eventually, the vasculature has been modelled with resistor-inductor-capacitor (RLC) direct circuits and have been linked to the rest of the system through a series connection. After simulating physiological conditions, HC has been simulated by changing pressure inputs and constant RLC parameters. Then, AIS occurring in arteries of different sizes have been simulated by considering time-dependent RLC parameters due to the elimination from the model of the occluding artery; instantaneous changes in hemodynamics have been evaluated by Systemic Arteriolar Flow (Qa) and Systemic Arteriolar Pressure (Pa) drop with respect to those measured in HC. Occlusion of arteries of different sizes leaded to an average Qa drop of 0.38 ml/s per cardiac cycle (with minimum and maximum values of 0.04 ml/s and 1.93 ml/s) and average Pa drop of 0.39 mmHg, (with minimum and maximum values of 0.04 mmHg and 1.98 mmHg). In conclusion, hemodynamic variations due to AIS are very small with respect to HC. A direct relation between the inverse of the length of the artery in which the occlusion occurs and the hemodynamic variations has been highlighted; this may allow to link the severity of AIS to the length of the interested artery.

Electrical Modeling and Analysis of Human Respiratory System

The human respiratory system mainly consists of four parts namely trachea, main bronchi, bronchioles and alveoli respectively. The alveoli in the lungs are responsible for the transfer of oxygen and carbon-dioxide through capillaries blood vessels leading to the pulmonary vein. A person cannot breathe properly during Chronic Obstructive Pulmonary Disease (COPD) due to abnormal transfer of oxygen and carbon-dioxide. Artificial ventilation is recommended for a person who suffers from COPD with no breathing or abnormal breathing, to manually preserve intact brain function. So, the blood oxygen level required for the person should be continuously monitored using pulse oximeter and controlled automatically using artificial ventilation. Hence, in this paper human respiratory system is modelled as analogies electrical model by using RLC parameters. The analogous electrical model parameters are represented as resistance, inheritance and compliance respectively. Using this analogous electrical model of human respiratory system, time domain and stability analysis are performed to identify COPD condition.

Modeling frequency response of transformer winding to investigate the influence of RLC

&lt;span&gt;Frequency response measurements are used for power transformer winding failures detection. The variation between frequency responses indicate mechanical changes in the transformer winding. One method to investigate winding failures in transformer is to develop a reliable circuit model which can simulate the frequency response of an actual winding. The main reason to use the model is because it is expensive to create damages on an actual winding. This paper proposes n-stages circuit ladder network to simulate the response of a winding which has unique design. It presents a new technique to calculate the resistance, inductance and capacitance of the winding. Then, the relationship between the RLC parameters and the frequency response is studied. The winding chosen in this investigation is a single phase 33kV transformer winding. The simulated frequency response was compared with the measured response to verify the proposed model. The model can give a comprehensive understanding about the effect of RLC parameters on the frequency response.&lt;/span&gt;

Accurate Extraction of Equivalent Circuit Parameters of Spiral Resonators for the Design of Metamaterials

Spiral resonators (SRs) are one of the most common typologies of resonant magnetic unit cell for the realization of metamaterials. The precise knowledge of their lumped electric properties (RLC parameters) is of crucial importance in the metamaterial design. Thus, an accurate and unambiguous procedure for estimating the value of the RLC lumped parameters of compact SRs is introduced. The proposed procedure relies on a rigorous approach allowing a complete characterization of SRs also in terms of $Q$ -factor. The method is general and valid for other shapes of resonators. The estimations have been finally verified by performing measurements on fabricated SRs through a magnetic probe.

Teaching Forced Damped Oscillator Using RLC Circuit Through Inverse Modeling

Teaching by direct models in science has been weakening the learning process of the students, because the real problems in engineering are not solved by direct models instead commonly they are solved by inverse models. On the other hand, one of the most relevant topics in the course of waves and particle physics oriented for the forming engineers; it's the subject of simple harmonic motion forced damping, which many physical phenomena can be explained as the quality factor Q and the resonance frequency of an oscillatory forced system. In order to capture the attention of students and give an application to this issue. We have developed an experimental setup to take measurements of electric current, voltages from capacitor and inductor for different frequencies and resistances, once the experimental data were collected to study the behavior of the electrical current inside the circuit and find out the RLC parameters with an inverse model. Finally, we want to show the process in detail how parameters of the system (Resistance, Inductance and Capacitance values) are very relevant in this kind of systems, from the results obtained by experimental measurements of voltage, current and angle of phase shift, where this was achieved by implementing an indirect method described in this document, so that can be applied to studies of more complex systems such as a motor where such parameters may be unknown.

Equivalent Resonant Circuit Modeling of a Graphene-Based Bowtie Antenna

The resonance performance analysis of graphene antennas is a challenging problem for full-wave electromagnetic simulators due to the trade-off between the computer resource and the accuracy of results. In this paper, an equivalent circuit model is presented to provide a concise and fast way to analyze the graphene-based THz bowtie antenna. Based on the simulated results of the frequency responses of the antenna, a suitable equivalent circuit of Resistor-Inductor-Capacitor (RLC) series is proposed to describe the antenna. Then the RLC parameters are extracted by considering the graphene bowtie antenna as a one-port resonator. Parametric analyses, including chemical potential, arm length, relaxation time, and substrate thickness, are presented based on the proposed equivalent circuit model. Antenna input resistance R is a significant parameter in this model. Validation is performed by comparing the calculated R values with the ones from full-wave simulation. By applying different parameters to the graphene bowtie antenna, a set of R, L, and C values are obtained and analyzed comprehensively. A very good agreement is observed between the equivalent model and the numerical simulation. This work sheds light on the graphene-based bowtie antenna’s initial design and paves the way for future research and applications.

Influence of material uncertainties on the RLC parameters of wound inductors modeled using the finite element method

Abstract In this work, we highlight the influence of the material uncertainties (magnetic permeability, electric conductivity of a Mn-Zn ferrite core, and electric permittivity of wire insulation) on the RLC parameters of a wound inductor extracted from the finite element method. To that end, the finite element method is embedded in a Monte Carlo simulation. We show that considering mentioned different material properties as real random variables, leads to significant variations in the distributions of the RLC parameters.

Portable RLC Parameter Measurement Instrument Based on The FPGA

This paper introduces a new type of digital portable RLC parameter measurement instrument. It uses direct frequency synthesis (DDS) technology, composed of FPGA direct generation measuring the sine wave digital signal. Freedom of choice shaft voltammetry measurement principle, with five end measurement method to ensure the measurement circuit concise high efficient; design a new digital full wave phase discriminator and improve the precision of phase. High-speed AD with FPGA for data acquisition and processing, make the whole system volume small, fast operation, high measurement accuracy, the complex scene and function to meet the design requirement.

Kalman filter estimation of RLC parameters for UMP transmission line

This paper present the development of Kalman filter that allows evaluation in the estimation of resistance (R), inductance (L), and capacitance (C) values for Universiti Malaysia Pahang (UMP) short transmission line. To overcome the weaknesses of existing system such as power losses in the transmission line, Kalman Filter can be a better solution to estimate the parameters. The aim of this paper is to estimate RLC values by using Kalman filter that in the end can increase the system efficiency in UMP. In this research, matlab simulink model is developed to analyse the UMP short transmission line by considering different noise conditions to reprint certain unknown parameters which are difficult to predict. The data is then used for comparison purposes between calculated and estimated values. The results have illustrated that the Kalman Filter estimate accurately the RLC parameters with less error. The comparison of accuracy between Kalman Filter and Least Square method is also presented to evaluate their performances.

Influence of the Geometric Uncertainties on the RLC Parameters of Wound Inductors Modeled Using the Finite-Element Method

In this paper, we highlight the influence of geometrical uncertainties (winding pattern and wire diameter) on the RLC parameters of wound magnetic components. To that end, the finite-element method is embedded in a Monte Carlo simulation in order to compute probability distributions of the parameters. An algorithm to randomly generate realistic winding configurations is also proposed.