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Article
Publication date: 4 April 2022

Alexander Yu. Lyashkov, Vladimir O. Makarov and Yevhen G. Plakhtii

The paper aims to substantiate optimization directions of resettable fuses parameters to protect solar arrays from overcurrent.

Abstract

Purpose

The paper aims to substantiate optimization directions of resettable fuses parameters to protect solar arrays from overcurrent.

Design/methodology/approach

The method of modeling the electrophysical characteristics of resettable fuses is used.

Findings

Resettable fuses currently produced are of little use for protecting photovoltaic cells (PVC) in solar arrays from overcurrent. The volume fraction of the conductive filler should be about 0.15, near the percolation threshold. Thus, reducing the resistance by increasing the amount of filler is not possible. The matrix of the composite should consist of a material with a significant proportion of the crystalline phase to ensure a sharp increase in the composite's volume near the melting point. Using a polymer with a lower melting point instead of polyethylene can reduce the power required to switch a resettable fuses.

Originality/value

The possibility of using resettable fuses based on polymer composite materials with a positive temperature coefficient of resistance to protect photovoltaic solar cells from current overloads is considered. Modeling of the electrophysical characteristics of modern industrial fuses of this type based on polyethylene-nanocarbon composites has been carried out. The limits of their applicability for the protection of photovoltaic solar cells are analyzed. On the basis of the obtained results, the optimization directions of the resettable fuses parameters for use in the protection circuits of PVC of solar array are determined.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 2
Type: Research Article
ISSN: 1573-6105

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 by using…

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: 4 August 2014

Thomas Maeder, Caroline Jacq, Ludivine Ammon and Perer Ryser

The purpose of this paper is to study tuneable positive temperature coefficient (PTC) effect in polymer-wax-carbon composite resistors. The resistivity dependence on temperature…

Abstract

Purpose

The purpose of this paper is to study tuneable positive temperature coefficient (PTC) effect in polymer-wax-carbon composite resistors. The resistivity dependence on temperature of composite resistors made of carbon fillers dispersed in an organic matrix is known to be strongly affected by the matrix thermal expansion. High PTC effects, i.e. essentially switching from resistive to quasi-insulating behaviour, can be caused by phase changes in the matrix and the assorted volume expansion, a behaviour that has been previously shown with both simple organic waxes and semi-crystalline polymers. However, waxes become very liquid on melting, possibly resulting in carbon sedimentation, and tuneability of semi-crystalline polymers is limited.

Design/methodology/approach

The authors therefore study a ternary polymer-wax-conductor (ethylcellulose-octadecanol-graphite) composite resistor system, where polymer and wax fuse to a viscous liquid on heating, and re-solidify and separate by crystallisation of the wax on cooling.

Findings

It is shown that with appropriate formulation, the resulting resistors exhibit strong PTC effects, linked with the melting and crystallisation of the wax component. The behaviour somewhat depends on sample history, and notably cooling speed.

Research limitations/implications

The phase equilibria and transformation kinetics of the polymer-wax system (including possible wax polymorphism), as well as the exact mechanism of the conductivity transition, remain to be investigated.

Originality/value

As many compatible polymer-wax systems with different melting/solidification behaviours are available, ternary polymer-wax-conductor composite PTC resistors allow a high tuneability of properties. Moreover, the high viscosity in the liquid state should largely avoid the sedimentation issues present with binary wax-conductor systems.

Details

Microelectronics International, vol. 31 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 26 September 2023

Alexander Sergeevich Tonkoshkur and Alexander Vladimirovich Ivanchenko

The purpose of this study is to model the dependences of the output voltage, temperature, current and electrical power dissipation of a voltage limiter based on a two-layer…

Abstract

Purpose

The purpose of this study is to model the dependences of the output voltage, temperature, current and electrical power dissipation of a voltage limiter based on a two-layer varistor–posistor structure on time and analysis the influence of operating modes and design parameters of such a limiter on these characteristics.

Design/methodology/approach

The behavior of the limiting voltage, temperature and other parameters of the voltage limiter when an input constant overvoltage is applied is studied by the simulation method. The voltage limiter was a two-layer construction. One layer was a zinc oxide ceramic varistor. The second layer was a posistor polymer composite with a nanocarbon filler of PolySwitch technology.

Findings

The output voltage across the varistor layer decreases and reaches some fixed value related to its breakdown voltage after applying a constant overvoltage to the structure over time. The temperature of the structure increases to some steady state value, while the current decreases significantly. The amplitude of the transient current pulse increases, its duration and energy of the transient process decrease with increasing overvoltage. An increase in the internal resistance of the overvoltage source can cause a decrease in the amplitude and an increase in the duration of transient currents.

Originality/value

The ranges of values for the activation energy of conduction of the varistor layer in weak electric fields, the intensity of heat exchange between the structure under study and the environment are determined to ensure the stable operation of this structure as a voltage limiter. The results obtained make it possible to select the necessary parameters of the indicated structures to ensure the required operating modes of the voltage limiter for various applications.

Article
Publication date: 1 September 2004

Christine Connolly

A new material has been developed consisting of metal particles intimately distributed in a polymer. This composite becomes a conductor under compression, tension or twisting…

Abstract

A new material has been developed consisting of metal particles intimately distributed in a polymer. This composite becomes a conductor under compression, tension or twisting, exhibiting a resistive range of one trillion to one, and following a smooth, repeatable curve. It has been shown that the conductivity arises from the quantum tunnelling effect. The material is used in a wide range of switches and sensors, as a replacement in standard components and also in novel applications.

Details

Sensor Review, vol. 24 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article
Publication date: 1 March 1999

29

Abstract

Details

Sensor Review, vol. 19 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article
Publication date: 1 March 1999

Clive Loughlin

224

Abstract

Details

Sensor Review, vol. 19 no. 1
Type: Research Article
ISSN: 0260-2288

Article
Publication date: 1 April 1991

Jack Hollingum

In the early 1980s Elmwood Sensors, part of Hawker Siddeley's Instruments and Controls Division, was totally reliant on a single 15‐year‐old product range of electro‐mechanical…

Abstract

In the early 1980s Elmwood Sensors, part of Hawker Siddeley's Instruments and Controls Division, was totally reliant on a single 15‐year‐old product range of electro‐mechanical thermostats using a bimetallic strip. Dissatisfied with this insecure situation and uncertain about the long‐term sales life for electromechanical sensors, the company decided that it should start looking for advanced technology substitutes.

Details

Sensor Review, vol. 11 no. 4
Type: Research Article
ISSN: 0260-2288

Article
Publication date: 1 July 1959

Brother D.A. Rock

Nowadays there is little need to argue the case for providing a low voltage system in science laboratories — for physics at least. However, there is still much argument about the…

Abstract

Nowadays there is little need to argue the case for providing a low voltage system in science laboratories — for physics at least. However, there is still much argument about the relative merits of different low voltage systems and it is difficult to choose between them. This article attempts to clarify the problem in three ways: first, it outlines the main features which are desirable in any low voltage system, then it attempts a comparison of some commonly used low voltage systems with respect to these and certain other important criteria, and finally it describes a new unit which seems close to providing a solution to the problem.

Details

Education + Training, vol. 1 no. 7
Type: Research Article
ISSN: 0040-0912

Article
Publication date: 1 July 1972

D.O. BURNS and BSc(Eng) FIEE

Remote power control basically means control at a distance of major switching operations in a generating and distribution system.

Abstract

Remote power control basically means control at a distance of major switching operations in a generating and distribution system.

Details

Aircraft Engineering and Aerospace Technology, vol. 44 no. 7
Type: Research Article
ISSN: 0002-2667

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