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Article
Publication date: 15 November 2019

Li Xiong, Xinguo Zhang and Yan Chen

The ammeter can measure the direct current and low-frequency alternating current through the wires, but it is difficult to measure complex waveforms. The oscilloscope can measure…

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Abstract

Purpose

The ammeter can measure the direct current and low-frequency alternating current through the wires, but it is difficult to measure complex waveforms. The oscilloscope can measure complex waveforms, but it is easy to measure the voltage waveform and difficult to measure the current waveform. Thus, how to measure complex current waveforms with oscilloscope is an important and crucial issue that needs to be solved in practical engineering applications. To solve the above problems, an active short circuit line method is proposed to measure the volt-ampere characteristic curve of chaotic circuits.

Design/methodology/approach

In this paper, an active short circuit line method is proposed to measure the volt-ampere characteristic curve of various chaotic circuits especially for memristive systems. A memristor-based chaotic system is introduced, and the corresponding memristor-based circuit is constructed and implemented by using electronic components.

Findings

The chaotic attractors and volt-ampere characteristic curve of the memristor-based chaotic circuit are successfully analyzed and verified by oscilloscope measurement with the proposed active short circuit line method. Accordingly, the hardware circuit experiments are carried out to validate the effectiveness and feasibility of the active short circuit line method for these chaotic circuits. A good agreement is shown between the numerical simulations and the experimental results.

Originality/value

The primary contributions of this paper are as follows: an active short circuit line method for measuring the volt-ampere characteristic curve of chaotic circuits is proposed for the first time. A memristor-based chaotic system is also constructed by using memristor as nonlinear term. Then, the active short circuit line method is applied to measure the volt-ampere characteristic curve of the corresponding memristor-based chaotic circuit.

Article
Publication date: 6 May 2020

Poornima Sridharan and Pugazhendhi Sugumaran C.

An annual substation equipment failure report says 3/7 capacitive voltage transformer (CVT) got damaged because of ferroresonance overvoltage. The conventional mitigation circuit…

Abstract

Purpose

An annual substation equipment failure report says 3/7 capacitive voltage transformer (CVT) got damaged because of ferroresonance overvoltage. The conventional mitigation circuit fails to protect the transformer as the overvoltage may fall in the range between 2 and 4 per unit. It is necessary to develop a device to suppress the overvoltage as well as overcurrent of the CVT. This study aims to propose the suitability of memristor emulator as a mitigation circuit for ferroresonance.

Design/methodology/approach

The literature implies that a nonlinear circuit can protect the transformer against ferroresonance. An attempt is made with a memristor emulator using Operational Amplifier (OPAMP) for the mitigation of ferroresonance in a prototype transformer. The circuit is simulated using PSpice and validated for its ideal characteristics using hardware implementation. The nonlinear memductance is designed which is required to mitigate the ferroresonance. The mitigation performance has been compared with conventional method along with fast Fourier transform (FFT) analysis.

Findings

While the linear resistor recovers the secondary voltage by 74.1%, the memristor emulator does it by 82.05% during ferroresonance. Also, the total harmonic distortion (THD) of ferroresonance signal found to be 22.06% got improved as 2.56% using memristor emulator.

Research limitations/implications

The suitability of memristor emulator as a mitigation circuit for ferroresonance is proposed in this paper. As ferroresonance occurs in instrument transformers which have extra high voltage (EHV) rated primary windings and (110 V/[110 V/1.732]) rated secondary windings, the mitigation device is proposed to be connected as a nonlinear load across the secondary windings of the transformer. This paper discusses the preliminary work of ferroresonance mitigation in a prototype transformer. The mitigation circuit may have memristor or meminductor for ferroresonance mitigation when they are commercially available in future.

Practical implications

The electronic component-based memristor emulator may not work at 110 V practically as they may be rated at low power. Hence, chemical component-based memristor emulator was developed to do the same. The authors like to clarify that the memristor will be a solution for ferroresonance in future not the memristor emulator circuit.

Social implications

With the real form of memristor, the transistor world will be replaced by it and may have a revolution in the field of electronics, VLSI, etc. This contribution attempts to project the use of memristor in a smaller scale in high-voltage engineering.

Originality/value

The electronic component-based memristor emulator is proposed as a mitigation circuit for ferroresonance. The hypothesis has been verified successfully in a prototype transformer. Testing circuit of memristor emulator involves transformer, practically. The mitigation performance has been compared with conventional method technically and justified with FFT analysis.

Details

Circuit World, vol. 47 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 5 March 2021

Kapil Bhardwaj and Mayank Srivastava

The purpose of the paper is to report an emulation configuration of a three pinch-off memristor (TPM), whose transient characteristics consist three cross-over points on the…

Abstract

Purpose

The purpose of the paper is to report an emulation configuration of a three pinch-off memristor (TPM), whose transient characteristics consist three cross-over points on the voltage-current plane, which is dissimilar to a conventional memristor. These characteristics can be very useful in memristor-based multi-bit memory devices and hyperchaotic oscillators.

Design/methodology/approach

The work describes the Mathematical framework for TPM and a circuit emulator based on the derived conditions. The configuration is based on five operational transconductance amplifier (OTAs) and four grounded passive elements. After which, we have verified its operation using personal simulation program with integrated circuit emphasis simulation environment. Finally, the implementation of OTA-based TPM using commercial integrated circuit (IC) LM13700 has also been presented.

Findings

It has been shown that a flux-dependent memductance expression of cubic order can show three intersections on the VI contour under certain parameter related constraints. Moreover, the OTA-based emulator reported in the work is very compact in nature because of the no use of external multiplier IC/circuitry, which has been popular in previous emulators.

Originality/value

For the first time, a multiple cross-over memristor emulator has been reported which can operate under practical operating conditions such as at practical operating frequencies and sinusoidal excitation.

Details

Circuit World, vol. 48 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 3 August 2022

Bin Zhao, Yawei Zhou, Junfeng Qu, Fei Yin, Shaoqing Yin, Yongwei Chang and Wu Zhang

Since carbon nanotubes (CNTs) were discovered by Iijima in 1991, they have gained more and more attention by people because of their unique physical and chemical properties. The…

Abstract

Purpose

Since carbon nanotubes (CNTs) were discovered by Iijima in 1991, they have gained more and more attention by people because of their unique physical and chemical properties. The CNTs have one-dimensional nanostructure, high surface adsorption capacity, good conductivity and electronic ballistic transmission characteristics and therefore have excellent mechanical, electrical, physical and chemical properties. CNTs are ideal basic materials to make nanometer gas sensors. Nanometallic materials function as to enhance electrode activity and promote the electron transfer, so if composite nanometallic materials M (such as Au, Pt, Cu and Pd) and CNTs are used, all kinds of their characters of components would have coeffect. Electrochemical sensors by use of such composite as electrode would have a higher detection sensitivity.

Design/methodology/approach

CNTs were synthesized via chemical vapor deposition technique and were purified afterward. CNTs-M(Pt,Au) suspension was prepared by chemical deposition using spinning disc processor (SDP) and was coated on gold electrode. The modified electrodes were constructed, based on immobilization of glucose oxidase on an Au electrode by electrostatic effect. CNTs-Pt/ glassy carbon electrodes (GCE) electrodes were made by electrochemically deposition of platinum particles on GCE modified by CNTs. The microstructures of the harvested CNTs, CNTs-M (M = Au, Pt) were analyzed under scanning electron microscopy and transmission electron microscopy. The application of the sensor in medical detection has been evaluated.

Findings

The results shown that CNTs-Au biosensors exhibit good reproducibility, stability and fast response to glucose detection, it can be used in the clinic detection of glucose concentration in human serum. Using CNTs-Pt/GCE for formaldehyde detection exhibited high sensitivity and good reproducibility.

Originality/value

This study modified CNTs by using self-assembled techniques through SDP with nano Pt and Au by electrodeposition for the first time. CNTs-Pt/GCE electrode was prepared by depositing platinum particles electrochemically on GCE modified by CNTs. CNTs-Au-modified electrode was prepared by immobilization of glucose oxidase on an Au electrode first by electrostatic effect. Electrochemical behaviors of glucose at CNTs-Au and formaldehyde at CNTs-Pt/GCE were investigated by cyclic voltammetry.

Details

Sensor Review, vol. 42 no. 5
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 28 March 2023

Yixuan Li, Yanfeng Chen, Bo Zhang, Dongyuan Qiu, Fan Xie and Chao Cheng

The purpose of this paper is to find a simpler model for the reactance components in the high-frequency range on the premise of ensuring the accuracy.

Abstract

Purpose

The purpose of this paper is to find a simpler model for the reactance components in the high-frequency range on the premise of ensuring the accuracy.

Design/methodology/approach

In this paper, based on the fractional calculus theory and the traditional integer-order model, a reactance model suitable for high frequency is constructed, and the mutation cross differential evolution algorithm is used to identify the parameters in the model.

Findings

By comparing the integer-order model, high-frequency fractional-order model and the actual impedance characteristic curve of inductance and capacitance, it is verified that the proposed model can more accurately reflect the high-frequency characteristics of inductance and capacitance. The simulation and experimental results show that the oscillator constructed based on the proposed model can analyze the frequency and output waveform of the oscillator more accurately.

Originality/value

The model proposed in this paper has a simple structure and contains only two parameters to be identified. At the same time, the model has high precision. The fitting errors of impedance curve and phase-frequency characteristic curve are less than 5%. Therefore, the proposed model is helpful to improve the simplicity and accuracy of circuit system analysis and design.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 42 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 May 2006

C. Wang, Z. Huang, X. Bai, N. Huang and B. Wang

To evaluate the photoelectrochemical characteristics of polymer doped with CdSe and CdSe/TiO2 for improved photoelectric conversion efficiency.

Abstract

Purpose

To evaluate the photoelectrochemical characteristics of polymer doped with CdSe and CdSe/TiO2 for improved photoelectric conversion efficiency.

Design/methodology/approach

A method was set‐up to dope the nano‐CdSe with poly‐perylene‐tetracarboxylic imide (PPI) in the nano‐TiO2/ITO films, which were characterised by X‐ray diffraction; electrochemical analytical system; multifunctional grating spectrometer; digital photometer and ultrasonic cleanout instrument, etc.

Findings

The modification of PPI doped with CdSe and CdSe/TiO2 showed significant elevation of the monochromatic incident photo‐to‐electron conversion efficiency (IPCE) of the photoelectrode, which was about 3 per cent. The doping caused a tone up separate efficiency of charge, restraining the complex of electron‐cavity by doped nano‐CdSe. Therefore, the photocurrent of the TiO2 film doped with nano‐CdSe was about three times higher than that without.

Research limitations/implications

The mixed film could also be formed from conjugated polymer mixed with polymer and inorganic particle, based on polymer doped with CdSe and CdSe/TiO2. In addition, the monochromatic incident IPCE of the photoelectrode needs to be extensively studied.

Practical implications

The treatment method developed provided a practical and effective solution to increasing the ICPE.

Originality/value

The method for doping polymer with CdSe and CdSe/TiO2 was novel and could probably be adapted for the manufacture of solar cell.

Details

Pigment & Resin Technology, vol. 35 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 December 1951

R.L Aspden

THE last decade has seen great progress in the development of the electronic flash tube and there are today few scientific or engineering projects which do not employ the tube as…

Abstract

THE last decade has seen great progress in the development of the electronic flash tube and there are today few scientific or engineering projects which do not employ the tube as a high‐speed photographic light source to secure data which cannot otherwise be obtained. Aeronautical research is no exception; the technique of flash photography was accelerated during the war years, both in this country and America, primarily to meet the many and varied problems which arise in aircraft engineering.

Details

Aircraft Engineering and Aerospace Technology, vol. 23 no. 12
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 5 May 2015

Mykhaylo Zagirnyak, Mariia Maliakova and Andrii Kalinov

Analytical determination of harmonic components of current in electric circuits containing semiconductor converters with the use of a small parameter method (SPM) in frequency…

Abstract

Purpose

Analytical determination of harmonic components of current in electric circuits containing semiconductor converters with the use of a small parameter method (SPM) in frequency domain. The paper aims to discuss these issues.

Design/methodology/approach

A SPM realized in frequency domain was used in the analytical analysis of electric circuits with semiconductor converters. An automated method of formation of orthogonal harmonic components of electrical values on the basis of discrete convolution algorithm was used to provide the possibility of realization of calculation in frequency domain. A nonlinear characteristic of a semiconductor converter was presented by the method of numerical approximation. A numerical structured simulation method was applied to determination of the reference values of current in the analyzed circuit. Laws of theoretical electrical engineering were used for formation of the equations of voltage balance in the circuit with a nonlinear element.

Findings

It is shown that application of a SPM with its realization in frequency domain enables significant simplification of the process of the analysis of electric circuits with semiconductor converters in an analytical form and facilitation of calculation automation. Analytical and numerical calculation of a circuit with a diode under active-inductive load demonstrated efficiency and sufficient accuracy of the proposed method. It is shown that increase of the order of approximating polynomial and of the number of the analyzed harmonics provides the improvement of the accuracy of numerical calculations.

Practical implications

The results of the work can be used in calculation of electrotechnical devices containing semiconductor appliances and electric devices with nonlinear characteristics. Moreover, the obtained results enable studying the processes of compensation of current higher harmonics in electric networks with a nonlinear load containing semiconductor converters.

Originality/value

For the first time it was proposed to apply a SPM with its realization in frequency domain to the analysis of nonlinear electric circuits. The significance of the paper consists in the fact that the offered method makes it possible to carry out both circuit analytical and numerical analysis with the possibility of its automation.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 July 2014

Yifan Wang and Guozhu Chen

As arc suppression coils (ASCs), magnetically controlled reactors (MCRs) are usually operated in the single-phase mode. Due to the lack of a third order harmonic compensation…

Abstract

Purpose

As arc suppression coils (ASCs), magnetically controlled reactors (MCRs) are usually operated in the single-phase mode. Due to the lack of a third order harmonic compensation circuit, the current harmonics are high. The purpose of this paper is to propose a novel structure of MCR and a genetic algorithm (GA) to determine the parameters which will result in minimum total harmonics.

Design/methodology/approach

This paper proposes the structure and the working principle of the multi-valve controlled saturable reactor (MCSR). There are several sorts of magnetic valves in the iron cores of the MCSR. The saturation degree of each magnetic valve is different when the same direct component of the magnetic flux is generated in the iron core, therefore current harmonics of different phases emerging, i.e. the total harmonics can be reduced. The magnetization characteristics and the mathematical model of the current harmonics of the MCSR are presented by introducing three parameters. The optimal values of the parameters that result in the smallest total harmonic distortion in the output current are calculated by a GA.

Findings

The simulation and experimental results are coincident with the theoretical analyses, which prove the effectiveness of the proposed method on harmonic suppression.

Practical implications

The method proposed in this paper can successfully reduce the current harmonics of the conventional MCR, including but not limited to the ASC. A prototype MCSR (540 kVA/10 kV) has been designed and constructed.

Originality/value

In this paper, a MCSR is proposed. The mathematical model of the MCSR for harmonic analysis is developed. The optimal parameters that result in the smallest THD in the output current are calculated. The mathematical model can be also used for the harmonic analysis of conventional MCRs.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 February 1989

Bennett J. Price

Uninterruptible Power Supply (UPS) systems are typically designed to provide power to computers for five to thirty minutes after all utility company power has failed. In addition…

Abstract

Uninterruptible Power Supply (UPS) systems are typically designed to provide power to computers for five to thirty minutes after all utility company power has failed. In addition to providing blackout and brownout protection, many UPS systems also protect against spikes, surges, sags, and noise, and some also offer many of the features found in power distribution units (PDUs). The major components or subsystems of a typical UPS system are detailed, and a sample bid specification is appended. Three sidebars discuss UPSs and air conditioning, the maintenance bypass switch (MBS), and literature for further reading.

Details

Library Hi Tech, vol. 7 no. 2
Type: Research Article
ISSN: 0737-8831

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