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Article
Publication date: 16 May 2019

Shouyi Han, Chuang Liu, Xiaodong Sun and Kaikai Diao

This paper aims to propose an effective method to verify poles polarities of switched reluctance motors (SRMs). Different from the ways of detection poles polarities by…

Abstract

Purpose

This paper aims to propose an effective method to verify poles polarities of switched reluctance motors (SRMs). Different from the ways of detection poles polarities by permanent magnet in SRMs, the difference of self-inductance between different winding connections is used to verify the pole polarity.

Design/methodology/approach

First, the winding connections with the forward and reverse series are proposed. The magnetic circuit models are established to analyze the flux linkage of different winding connections. Then, according to the difference of inductance characteristics, including the self-inductance and the mutual inductance affected by the adjacent poles, it is theoretically feasible to verify the polarity of each pole. Finally, the proposed method is verified by the simulation and experiment on a six-phase SRM.

Findings

First, compared to the reverse series, the forward series can produce larger self-inductance when one phase is excited at the same current excitation, which can be used to verify the poles polarities of one phase with different winding connection. Second, the mutual inductance can be used to distinguish the winding connections. Third, the difference of the maximum self-inductance of the winding, which is composed of two adjacent windings, can be used to verify the polarities of the adjacent poles.

Originality/value

This paper proposes an effective method to verify poles polarities of SRMs.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 19 June 2017

Yanhang Zhao, Jingang Wang, Shoupeng Ban, Xueqi Hu and Diancheng Si

The purpose of this paper is to design a current transformer model based on the principle of B-dot. It can reflect the change of transmission line current and meet the…

Abstract

Purpose

The purpose of this paper is to design a current transformer model based on the principle of B-dot. It can reflect the change of transmission line current and meet the requirement of automation and intelligence for current measurement in power system.

Design/methodology/approach

In this paper, a new type of current transformer is designed on the principle of B-dot, which has the structure of the inverse series of planar air core coils and the form of printed circuit board (PCB). With this structure, the current transformers can induce magnetic field quite well. The finite element simulation for the current transformer with n layers structure is conducted in the Maxwell, which help to optimize the design of the current transformer.

Findings

By setting up the experimental platform, the experiment of the current transformer is carried out. The results of the test show that the measurement accuracy can satisfy the requirement of measurement. Besides, the new current transformer has good transient characteristics and can meet the needs of the development of smart grid.

Originality value

The new type of current transformer is based on the principle of B-dot, which is designed with a new type of non-contact PCB hollow coil current transformer. It has no iron core, no ferromagnetic effect and the phenomenon of ferromagnetic resonance. It has great progress in its insulation performance, volume and bandwidth response. In addition, the planar hollow coil of the inverse series structure can make the structure more accurate.

Details

Sensor Review, vol. 37 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 9 December 2020

Xinning Tang, Yong Dai, Yunhui Ma and Bingyin Ren

This study aims to solve the problem of the existing metal foreign object (MFO) detecting systems, which are not sensitive to the small size MFO in wireless charging…

Abstract

Purpose

This study aims to solve the problem of the existing metal foreign object (MFO) detecting systems, which are not sensitive to the small size MFO in wireless charging region of electric vehicle (EV) because of the extremely complex signal noise in the process of wireless charging of EV.

Design/methodology/approach

A method for MFO detection based on the principle that MFOs can cause mistuned resonance of detection coil resonant circuit is proposed. The general scheme of detecting system is proposed. The design method for detection coils which is effective to small MFOs detection in large-area region of wireless charging of EV is presented. The design of time-sharing driving circuit and amplifying circuit of high frequency exciting signal for detection coils is introduced. The design scheme of signal processing circuit (including filter and rectifier) of detection coil terminal voltage is also proposed.

Findings

The influence of exciting frequency of detection coils on detecting sensitivity and the anti-noise feature of system are analyzed according to the experiment results.

Originality/value

The experiment of MFO detection indicates that the proposed method can effectively detect the coin-sized small MFO in the process of wireless charging of EV.

Details

Sensor Review, vol. 41 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 13 November 2019

A.S. Tonkoshkur and A.V. Ivanchenko

The purpose of this paper is to minimize and prevent current overloads (including the elimination of abnormal and fire hazardous situations) in photovoltaic solar arrays…

Abstract

Purpose

The purpose of this paper is to minimize and prevent current overloads (including the elimination of abnormal and fire hazardous situations) in photovoltaic solar arrays by using low-cost functional electronic elements, in particular, the new PolySwitch PPTC fuses.

Design/methodology/approach

The modeling method has been used to investigate the circuit solution of the use of PolySwitch type fuses to prevent and minimize current overloads in photovoltaic solar arrays.

Findings

It is shown that the limitation of the short-circuit current with parallel connection of photovoltaic components (photovoltaic cells or their modules) can be implemented when the following conditions are met: the resistance of the fuse in the conducting state is much lesser than the parallel connection of the series resistances of the photovoltaic components; and the tripping current of the fuse must be greater than the maximum current of the separate photovoltaic components and lesser than the current of a parallel connection of several photovoltaic components.

Originality/value

The influence of the magnitude of the resistance in the conducting state and the response current of the fuses to the current–voltage and volt–watt characteristics of parallel connections of the photovoltaic components (photovoltaic cells or their modules) is analyzed. The modeling results are confirmed by experimental data on the transformation research of light current–voltage and volt–watt characteristics of parallel connections of industrial photovoltaic modules using resettable fuses of the PolySwitch type.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 2 July 2020

Yihua Dou, Yufei Li, Yinping Cao, Yang Yu, Jiantao Zhang and Lin Zhang

To maintain the well integrity, the strength and sealing ability of premium connection should be in the safe scope. ISO 13679 is widely used for evaluating the ability of…

Abstract

Purpose

To maintain the well integrity, the strength and sealing ability of premium connection should be in the safe scope. ISO 13679 is widely used for evaluating the ability of tubing and casing connection all over the world. FE is adopted to simulate the ISO 13679 tests.

Design/methodology/approach

Because of the disadvantage of experiment such as long period, high cost and high requirement on the facility, considering the convenience and universality of finite element method, as well as the contacting nonlinearity and material nonlinearity, three-dimensional finite element model of a certain type of premium connection is established with the consideration of helix angle. The loads exerted on the premium connection are the loads in series B test and thermal cycle test of ISO 13679. The distributions of Von Mises stress and contact pressure in various cases were studied.

Findings

The results showed that the bending load has a great influence on the distribution of Von Mises stress and contact pressure for premium connection. The Von Mises stress and contact pressures on the sealing surface are smaller on the tension side and greater on the compression side. With increasing axial compression load, the contact pressures on the tension side are too small, which may lead to sealing failure. The influence of temperature on the performance of premium connection cannot be ignored when choosing or designing premium connections. Both the Von Mises stress and contact pressure decrease slightly during a period of thermal cycle. Although the performance of the premium connection is good in a period of thermal cycle, its performance in a long period should be evaluated. Finite element simulation can effectively simulate the ISO 13679 test procedure and obtain the stress and contact pressure distribution. It can be used as a reference for evaluating the performance of premium connections.

Originality/value

Considering the convenience and universality of finite element method, as well as the contacting nonlinearity and material nonlinearity, three-dimensional finite element model of a certain type of premium connection is established with the consideration of helix angle.

Details

International Journal of Structural Integrity, vol. 12 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 14 August 2017

Rudrajeet Pal

The purpose of this paper is to identify the major reverse logistics design aspects in used clothing value chains, and those enabling and challenging manifestation of…

2503

Abstract

Purpose

The purpose of this paper is to identify the major reverse logistics design aspects in used clothing value chains, and those enabling and challenging manifestation of value creation.

Design/methodology/approach

This research is based on an exploratory study of 12 established organizations in Swedish used clothing networks. Data were gathered through semi-structured interviews, secondary sources, and subsequent field visits.

Findings

Empirical insights on how various design aspects influence value creation in used clothing value chains are provided. Crucial among these are strategic and consistent collection, presence of multi-channel sales, and communication of post-retail concepts for manifesting value by bolstering consumer satisfaction, environmental motivation, and corporate image. Inter-organizational collaboration in reverse logistics processes and workplace training, further renders higher economic, environmental and information values.

Research limitations/implications

The paper proposes a holistic framework of design aspects in reverse value chains, and extends existing knowledge on how these aspects manifest value creation. By doing so, a nuanced view of the design aspects is offered by highlighting how they can differentially, either enable, or challenge value creation. In this connection, seven supporting propositions are developed for in-depth future research.

Practical implications

The paper includes implications for the devising strategic solutions for higher value creation, by understanding of the key enablers and challenges, for many actors in the used clothing networks.

Originality/value

The role of various design aspects in reverse value chains for manifesting multifaceted stakeholder value creation is explicitly defined in the paper.

Details

The International Journal of Logistics Management, vol. 28 no. 3
Type: Research Article
ISSN: 0957-4093

Keywords

Article
Publication date: 14 January 2021

Fatih Kızılaslan

The purpose of this paper is to investigate the stochastic comparisons of the parallel system with independent heterogeneous Gumbel components and series and parallel…

Abstract

Purpose

The purpose of this paper is to investigate the stochastic comparisons of the parallel system with independent heterogeneous Gumbel components and series and parallel systems with independent heterogeneous truncated Gumbel components in terms of various stochastic orderings.

Design/methodology/approach

The obtained results in this paper are obtained by using the vector majorization methods and results. First, the components of series and parallel systems are heterogeneous and having Gumbel or truncated Gumbel distributions. Second, multiple-outlier truncated Gumbel models are discussed for these systems. Then, the relationship between the systems having Gumbel components and Weibull components are considered. Finally, Monte Carlo simulations are performed to illustrate some obtained results.

Findings

The reversed hazard rate and likelihood ratio orderings are obtained for the parallel system of Gumbel components. Using these results, similar new results are derived for the series system of Weibull components. Stochastic comparisons for the series and parallel systems having truncated Gumbel components are established in terms of hazard rate, likelihood ratio and reversed hazard rate orderings. Some new results are also derived for the series and parallel systems of upper-truncated Weibull components.

Originality/value

To the best of our knowledge thus far, stochastic comparisons of series and parallel systems with Gumbel or truncated Gumble components have not been considered in the literature. Moreover, new results for Weibull and upper-truncated Weibull components are presented based on Gumbel case results.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 8
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 January 1978

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the…

1023

Abstract

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the 1970 Act (which has been amended by the Sex Discrimination Act 1975) provides:

Details

Managerial Law, vol. 21 no. 1
Type: Research Article
ISSN: 0309-0558

Article
Publication date: 30 September 2013

Nataraj Chandrasekharan, Jaehyung Ju and Lonny Thompson

A three-dimensional finite element (FE) model is developed to design a vibrating bimorph piezoelectric cantilever beam with lead zirconate titanate (PZT-5H) for energy…

Abstract

Purpose

A three-dimensional finite element (FE) model is developed to design a vibrating bimorph piezoelectric cantilever beam with lead zirconate titanate (PZT-5H) for energy harvesting. The paper aims to discuss these issues.

Design/methodology/approach

A parametric study of electric power generated as a function of the dielectric constant, transverse piezoelectric strain constant, length and thickness of the piezoelectric material, is conducted for a time-harmonic surface pressure load. Transversely isotropic elastic and piezoelectric properties are assigned to the bimorph layers with brass chosen as the substrate material in the three-dimensional FE model. Using design of experiments, a study was conducted to determine the sensitivity of power with respect to the geometric and material variables.

Findings

The numerical analysis shows that a uniform decrease in thickness and length coverage of the piezoelectric layers results in a nonlinear reduction in power amplitude, which suggests optimal values. The piezoelectric strain coefficient, d31 and the thickness of PZT-5H, tp, are the most important design parameters to generate high electric energy for bimorph vibration harvesting device.

Originality/value

The work demonstrates that, through a sensitivity analysis, the electro-mechanical piezoelectric coupling coefficient (d31) and the thickness of the piezoelectric strips (tp) are the most important parameters which have a significant effect on power harvested.

Details

Multidiscipline Modeling in Materials and Structures, vol. 9 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 1 August 1993

Zhanbo Yang

Following Ma, Yonghao and Yi Lin's definition of a mathematical model of general systems in 1987, shows the class of all general systems with relation‐reversion mappings…

Abstract

Following Ma, Yonghao and Yi Lin's definition of a mathematical model of general systems in 1987, shows the class of all general systems with relation‐reversion mappings and that of all general systems with relation‐preserving mappings to be productive, co‐productive categories Answers two questions posed in earlier published papers and poses some more questions for solution.

Details

Kybernetes, vol. 22 no. 8
Type: Research Article
ISSN: 0368-492X

Keywords

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