Application of varistor-posistor structure for protection from overvoltages of photovoltaic cells of solar arrays

Иванченко, А. В.; Тонкошкур, А. С.; Mazurik, S. V.

doi:10.15421/331913

Cited by 5 publications

(4 citation statements)

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“…In conclusion, we note that similar patterns were obtained by us [96] and when using a working varistor element (layer with a diameter of 13 mm and a thickness of The results of the study of the electrical characteristics of the structure based on the varistor ceramic layer and the posistor layer, which uses a polymer PPTC-nanocomposite, give reason to believe that such a device has certain unique functionality that makes it possible to implement DC overvoltage protection.…”

Section: Voltage Limitation For a Group Of Series-connected Photovoltaic Cellssupporting

confidence: 79%

Application of Polymer Posistor Nanocomposites in Systems for Protecting Photovoltaic Components of Solar Arrays From Electrical Overloads

Тонкошкур¹,

Иванченко²,

Nakashydze³

et al. 2021

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The experience of operating solar arrays indicates the need to solve the problem of creating effective and reliable switching elements to block defective and damaged photovoltaic cells. Available methods of solving this problem (for example, the use of transistor switches, electronic systems, etc.) either do not completely solve it, or are expensive. The tasks of increasing the reliability and efficiency of switching elements, preventing the destruction of photovoltaic cells which occurs during heating by dark current ("hot spots" and fire hazardous situations) are relevant. Recently, one of the promising solutions of this problem is the use of additional devices for isolating inactive (shaded or defective) areas of both separate photovoltaic cells and their modules. These devices are PPTC (polymeric positive temperature coefficient) resettable fuses of PolySwitch type, which are polymer composites with nanoscale carbon fillers. The basic functional property of PPTC fuse is an abrupt increase in electrical resistance by several orders of magnitude when a temperature is reached and a return to the initial high conductive state when the temperature drops. The advantages of such structures based on polymer composites with nanocarbon fillers include: – close to the metal resistance to the switching temperature and to the resistance of the insulator above the specified temperature; – possibility of realization in the form of discrete elements and continuous film-tapes (that is important at the decision of problems of realization of isolation of defective local area of the separate photovoltaic cell); – reaction in the form of temporary isolation of separate components of the solar array to increase their temperature. The research results are presented and the concept of overload protection by using resettable fuses based on polymer nanocomposite materials with nanocarbon fillers is substantiated in this paper. In particular, the expediency of series connection of PolySwitch fuses to photovoltaic modules with parallel connection of their strings is shown to prevent an abnormal situation, namely, a complete loss of electrical energy generated by such a string, which can occur when one of its modules is short-circuited. The circuit solutions in the form of combined structure based on layers of a varistor ceramics and a posistor polymer nanocomposite with carbon filler being in thermal contact are investigated. The prospect of its use to protect photovoltaic cells with a high reverse resistance from overvoltage is established. The problem of protection against local overheating in photovoltaic cells (or their parallel connections) by physical and technological methods, in particular, by creating photovoltaic cells with a built-in layer based on a posistor composite being in thermal contact with it, is analyzed. In general, the described results represent a new direction in the field of improving photovoltaic systems, in particular, in terms of increasing their efficiency, operating time and reliability by using solid-state devices based on polymer posistor nanocomposites and varistor ceramics as means of their protection from electrical and thermal overloads. Keywords: SOLAR ARRAY, PHOTOVOLTAIC MODULE, PHOTOVOLTAIC CELL, ELECTRIC OVERLOAD, POLYMER POSISTOR NANOCOMPOSITE, HOT SPOT, VARISTOR CERAMICS

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Section: Voltage Limitation For a Group Of Series-connected Photovoltaic Cellssupporting

confidence: 79%

Application of Polymer Posistor Nanocomposites in Systems for Protecting Photovoltaic Components of Solar Arrays From Electrical Overloads

Тонкошкур¹,

Иванченко²,

Nakashydze³

et al. 2021

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“…The current issue and full text archive of this journal is available on Emerald Insight at: https://www.emerald.com/insight/1573-6105.htm A small number of works (Tonkoshkur and Ivanchenko, 2019;Tonkoshkur et al, 2021;Ivanchenko et al, 2019) have been devoted to the study of the electrical characteristics of the considered two-layer varistor-posistor structures. In this case, mainly static characteristics were studied.…”

Section: Voltagelimiting Kinetics 1249mentioning

confidence: 99%

“…The tasks of developing the considered devices require detailed knowledge of their electrical and thermal characteristics and their behavior under various conditions, including transient process. This is due to the peculiarities of their optimal use as voltage limiters for general multipurpose use, resettable fuses from overvoltage in photovoltaic systems of solar array (Tonkoshkur et al, 2021;Ivanchenko et al, 2019).…”

Section: Voltagelimiting Kinetics 1249mentioning

confidence: 99%

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Modeling of voltage-limiting kinetics in two-layer varistor–posistor structures

Tonkoshkur,

Ivanchenko

2023

MMMS

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PurposeThe 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/approachThe 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.FindingsThe 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/valueThe 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.

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Electrical properties of photogalvanic element with built-in posistor layer based on polymer nanocomposite with carbon filler

Иванченко

Тонкошкур

2020

ТКЭА

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The study considers the problem of preventing overheat and thermal breakdown of a photovoltaic cell when a high reverse voltage is applied to its p—n junction. The overvoltage protection ability of a structure made up of a photovoltaic cell in direct thermal contact with a built-in posistor layer has been experimentally studied. Fragments of solar cells based on single-crystal silicon were used as a photovoltaic cells. The posistor layer was a polymer nanocomposite with carbon filler used in the resettable fuses of the “PolySwitch” technology. The authors study kinetics of changes in the electrical characteristics of such a structure under constant electric overvoltage on a shaded photovoltaic cell, when its p—n junction is turned on in the reverse direction. It is shown that the current and reverse voltage on the shaded photovoltaic cell are limited and reduced from the moment when the temperature of this structure reaches the values close to the temperature of the phase transition of the posistor nanocomposite to the low-conductive state, which is ≈ 125°С. With an increase in the overvoltage value, a decrease in the response time of the considered protection and an increase in the maximum current value through the structure under study are observed. A decrease in the current value required to reach the tripping temperature by the posistor layer can be achieved by reducing the thermal resistance of the contact between the photovoltaic and posistor elements of the structure. The results obtained indicate the possibility of implementing protection against reverse electrical overvoltage and thermal breakdown of photovoltaic systems based on photovoltaic cells with built-in fuse layers of a specified type.

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Application of varistor-posistor structure for protection from overvoltages of photovoltaic cells of solar arrays

Cited by 5 publications

References 10 publications

Application of Polymer Posistor Nanocomposites in Systems for Protecting Photovoltaic Components of Solar Arrays From Electrical Overloads

Application of Polymer Posistor Nanocomposites in Systems for Protecting Photovoltaic Components of Solar Arrays From Electrical Overloads

Modeling of voltage-limiting kinetics in two-layer varistor–posistor structures

Electrical properties of photogalvanic element with built-in posistor layer based on polymer nanocomposite with carbon filler

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