Мета роботи. Провести розрахунок енергетичного балансу фотоенергетичної установки для роботи в умовах концентрованого сонячного випромінювання, розробити конструкцію теплообмінного блоку з «мікро» каналами. Методи дослідження. Аналітичні дослідження за допомогою критеріальних рівнянь гідродинаміки, створення та дослідження комп’ютерних моделей на основі рівнянь теплового балансу. Отримані результати. На основі аналізу теплових процесів запропоновано конструкцію теплообмінного блоку оснащеного «мікро каналами» для комбінованої фотоенергетичної установки, що розрахована на роботу в умовах концентрованого сонячного випромінювання. Показано, що в такій конструкції створюється перехідний режим потоку рідини, що охолоджує, що дозволяє ефективно охолоджувати сонячні елементи в умовах концентрованого сонячного випромінювання. На основі результатів досліджень запропоновано шляхи покращення конструкції теплообмінного блоку для оснащення фотоенергетичної установки, розрахованої на роботу в умовах порушення типової енергоінфраструктури. Показано, що для зменшення перепаду температури за площею СЕ можливе перенесення входу теплоносія в центр і двох виходів на протилежних краях блоку. Наукова новизна. Вперше запропонована конструкція радіатора теплообмінного блоку на основі «мікроканалів», що забезпечує перехідний режим потоку з коефіцієнтом теплообміну між теплоносієм та верхньою пластиною радіатора hf ~ 10000 Вт/(м2⋅К) при швидкості потоку у проміжках між пластинами ~2.1 м/с. Практична цінність. Виконано оцінку ефективності, теплових та електричних характеристик комбінованої фотоенергетичної установки з концентрацією сонячного випромінювання. Запропоновано використання розробленої конструкції теплообмінного блоку для оснащення фотоенергетичної установки для роботи в умовах порушення типової енергоінфраструктури. Проведено попередній розрахунок теплових та електричних параметрів фотоенергетичної установки, оснащеної багатокаскадними сонячними елементами на основі арсеніду галію та теплообмінним блоком із «мікроканалами».

Purpose. Calculate the energy balance of a photo-energy installation for operation in conditions of concentrated solar radiation, develop the design of a heat exchange unit with "micro" channels. Methodology. Analytical studies using criterion equations of hydrodynamics, creation and study of computer models based on heat balance equations. Findings. Based on the analysis of thermal processes, the design of a heat exchange unit equipped with "micro channels" for a combined photoelectric plant designed to work in conditions of concentrated solar radiation is proposed. It is shown that such a design creates a transitional mode of cooling liquid flow, which allows for efficient cooling of solar cells under conditions of concentrated solar radiation. Based on the results of research, ways of improving the design of the heat exchange unit for equipping a photoelectric system designed to work in conditions of disruption of the typical energy infrastructure are proposed. It has been shown that in order to reduce the temperature difference over the SC area, the design of the heat exchange block can be optimized by moving the coolant inlet to the center and creating two exits at the opposite ends of the block. Originality. For the first time, the design of the radiator of the heat exchange unit based on "micro-channels" was proposed, which provides a transitional mode of coolant flow with a heat exchange coefficient between the coolant and the upper plate of the radiator. hf ~ 10000 W/(m2K) at a flow speed in the gaps between the plates ~2.1 m/s. Practical value. The evaluation of the efficiency, thermal and electrical characteristics of the combined photo-energy system with the concentration of solar radiation was performed. It is proposed to use the developed design of the heat exchange unit for equipping a photoelectric plant for operation in conditions of disruption of the typical energy infrastructure. A preliminary calculation of the thermal and electrical parameters of a photovoltaic installation equipped with multi-cascade solar cells based on gallium arsenide and a heat exchange unit with "microchannels" was carried out.

In recent years, the production of solar cells (SC) based on crystalline silicon has become cheaper and at the same time increased, thanks to which solar panels from the predominantly energy source of spacecraft have become a recognized energy resource with an installed capacity of 680 GW and maintains the highest growth rate.

Commissioning and experimental testing of technical capabilities and modes of operation were carried out, and test measurements of light current-voltage characteristics of solar cells were carried out using a modern measuring complex based on the Sunbrick sun simulator. Automated measurement of the light-voltage-current characteristics of solar cells by the compensation method using the Keithley 2400 measuring device was implemented. During the approbation of the measuring complex based on the Sunbrick sun simulator, the possibility of reproducing different modes of simulator operation was tested and the ability to control radiation in terms of energy in the range from 100 to 1100 W/m2 and by spectral composition. It was established that the spatial unevenness of illumination for the investigated device is less than 2 % with an illumination area of more than 400 cm2. It is shown that the tested measuring complex allows for automated research of solar cells in irradiation regimes corresponding to both terrestrial irradiation conditions and extraatmospheric solar radiation conditions. The possibility of individual adjustment of each of the 36 channels of the emitting element in the range from 400 to 1100 nm has been tested, which adds flexibility in the use of the Sunbrick sun simulator during the study of both solar cells as a whole and the properties of functional semiconductor materials by irradiation with monochromatic or mixed illumination. It is shown that due to the rapidity of conducting research and the ability to immediately visualize the measured current-voltage characteristic on the computer screen, it is possible to significantly speed up the process of researching solar cells. Thus, it is possible to immediately divide the investigated solar cells into groups in relation to their efficiency and determine the presence of possible defects or damage in their structure.

With the use of modernized industrial vacuum installations, a series of test samples of cadmium telluride films was produced by the method of thermal vacuum evaporation on glass substrates without a sublayer of transparent conductive oxide, with a sublayer of conductive oxide, and on molybdenum foil substrates to study the influence of the substrate material on the structural parameters of the test samples. The study of the structure was carried out by the method of X-ray diffractometric analysis, the parameters of the lattice, the sizes of the regions of coherent scattering and the texture coefficient of the film were calculated. Based on the results of research into the structural parameters of samples made on a glass substrate, the presence of a cubic phase of cadmium telluride was established. It is shown that when the temperature of the substrate increases, the texture of the samples increases and the presence of tensile stresses is observed, since the lattice period of the cubic phase is significantly higher than that of the tabular phase. For a sample obtained on a glass substrate with a layer of transparent conductive ITO oxide at a substrate temperature of 200 ОC, the presence of two hexagonal phases H1 and H2 and a cubic phase C was established. The samples obtained on a molybdenum foil substrate contain almost entirely the cubic CdTe phase only in very thin sample no. 1 traces of the hexagonal phase are present. For the first thinnest sample, only one main diffraction peak of the cubic phase is observed, which can be explained by the fact that in the initial stages of the film growth, it grows as a highly textured cubic phase with the possible presence of some hexagonal phase. From the analysis of the obtained results, it can be noted that the samples obtained on the molybdenum substrate have a lattice parameter closest to the table data - 6.482–6.483 Å. The structural differences observed between the studied samples are due to the fact that they have a different preferred orientation, which is most likely due to a change in the sputtering speed

The article presents the design conception of a high mobility energy generation and storage system with intelligent energy conversion and storage systems for use in military and civilian purposes in regions with damaged infrastructure, where access to electricity and hot water is limited or threatened due to man-made actions or natural damage.The proposed system main feature is modular design which combines a heat collector, electrical energy converter, and related energy storage systems.The modular, reliable design and ease of deployment of the proposed system, the size of which allows to carry out in standard shipping containers, enables rapid and flexible scaling of a deployed solar power plant, production and storage of electricity and hot water.The design of the module of the proposed system is based on the use of highly efficient multi-junction III-V solar cells in combination with economically and reliable plastic made system for concentrating solar radiation.At the same time, the cooling of solar cells to maintain their operating temperature provides heating of water to the minimum values required in domestic conditions.Also, the modular principle is the basis of the system for storing and distributing electrical energy, which is supposed to be made of highly efficient Li-Fe based rechargeable batteries, which today have one of the best indicators in terms of the ratio of volume and accumulated energy.An intelligent control system based on microcontrollers provides accurate positioning of solar cells, the implementation of the MPPT algorithm to maximize power generation and maintain a balance between supplying consumers and charging batteries.Modularity makes it possible to form emergency power supply complexes of different power (45 W of electric power and 50 W of thermal energy per one module) for provide emergency and permanent power supply of most electronic devices according to the standard protocols PD 3.0, QC 3.0, 12 V, 220 V as well as supply consumers with warm water for basic needs.

Purpose. The introduction of electronic load for testing high-precision low-voltage sources (solar panels) requires careful review not only of the circuit design, but also thermal and mechanical design. The article considers the principle of creating and calculating the optimal solution for the implementation of electronic load. Methodology. To achieve this goal, methods of analysis of modern electronic database, calculations of basic physical and electrical parameters and their modeling are used. Findings. Based on the considered physical and circuit solutions for the implementation of the electronic load unit, a corresponding electrical circuit was developed. The transistors are controlled by four unipolar operational amplifiers integrated into the LM324 chip. Control of the electronic load unit is implemented by controlling the voltage at the positive feedback terminals, which is further stabilized by the TL431 chip. The device is powered by a source of DC stabilized current of 12 V (provides additional filtering from voltage fluctuations). Originality. Modern advances in the development of solar cells and other low-voltage energy sources have led to the need to create compact and express systems for testing them, which cannot be implemented on existing solutions. Practical value. Adherence to the indications and principles set out in this article will provide the load with the ability to work at high power, while maintaining good performance and reliability. The developed scheme allows to create a compass device for express testing of solar panels.

One of the main requirements for modern radio electronic equipment is the issue of electromagnetic (EM) stability, which means the ability to maintain operating parameters during and after the action of pulsed EM radiation of various origins.The problem of ensuring EM stability is due to the fact that under the influence of EM pulses, overvoltage pulses appeared in the circuits, which is particularly prone to the destruction of semiconductor devices due to both the properties of the p-n junction and the specific thermal conductivity of semiconductor materials.At the same time, the effects of resistive switching are actively used in modern electronics, in particular, the work of memristors is based on resistive switching in oxides of transition metals.This effect of resistive switching has long been observed in CdTe, both on thick (more than 100 μm) single-crystal layers and in thin polycrystalline films.The novelty of the proposed work consists in the fact that switching processes between low and high conductivity states in CdTe films depend on various factors, such as the film thickness, its initial structure, the power of the switching pulse, and the contact properties.Thin film CdTe based structures were prepared by using vacuum deposition methods.The study of fast switching processes in manufactured Mo -cadmium telluride -Mo structures was carried out by measuring and further analytical processing of their amplitude-time characteristics under the action of EM pulses of nanosecond duration.It was found that the prototypes with a metallization diameter of 0.5 mm and 6 mm, made using the planar technology, have similar parameters: the switching time is at the level of 1-2 ns, similar values of the cutoff voltage and the course of its dependence on the pulse amplitude.The geometry of the contact metallization does not affect the switching parameters of structures, and in the manufacture of protection elements against EM pulses on their basis, an industrial technology for the formation of metallization can be used without the need for its excessive miniaturization.

In this work, nanocomposites of polyester fabric and biopolymer nanocellulose were developed as a textile backing for an efficient thermoelectric (TE) textile material with a nanostructured semiconductor film of copper iodide (CuI) 5 μm thick. Among the three methods for obtaining nanocellulose hydrogel from hemp organosolv pulp, thermochemical treatment with deep eutectic solvent turned out to be the best. This nanocellulose is composed of rod-shaped cellulose nanocrystals, which provide strength to the nanocomposite so that the TE textile sample does not crack. The CuI film in this thermoelectric textile has the best crystal structure, is non-stoichiometric, enriched in iodine, and has copper vacancies, which contributes to a large Seebeck coefficient and low resistivity, which ensures an increase in thermoelectric efficiency. The thermal image of the TE textile confirms the low thermal conductivity of the nanocomposite. Their maximum specific output power 15.6 $\mu \mathrm{W}/\text{cm}^{2}$ is one of the best among modern solid-state miniature, flexible and textile thermoelectric materials.

Мета роботи. Впровадження електронного навантаження для випробування високоточних низьковольтних джерел (сонячних батарей) вимагає ретельного перегляду не тільки схемотехнічної конструкції, а й теплотехнічної та механічної конструкції. У статті розглядається принцип створення та розрахунку оптимального рішення для реалізації електронного навантаження. Методологія. Для досягнення мети використовуються методи аналіза сучасної електронної бази, розрахунки основних фізичних та електричних параметрів та їх моделювання. Висновки. На основі розглянутих фізико-схемних рішень для реалізації електронного блоку навантаження була розроблена відповідна електрична схема. Транзистори керуються чотирма уніполярними операційними підсилювачами, інтегрованими в мікросхему LM324. Управління електронним блоком навантаження реалізується шляхом управління напругою на клемах позитивного зворотного зв'язку, яка додатково стабілізується мікросхемою TL431. Пристрій живиться від джерела постійного стабілізованого струму напругою 12 В (забезпечує додаткову фільтрацію від коливань напруги). Оригінальність. Сучасні досягнення у розробці сонячних елементів та інших низьковольтних джерел енергії призвели до необхідності створення компактних та експресних систем їх тестування, котрі не можна реалізувати на існуючих рішеннях. Практичне значення. Дотримання показань і принципів, які викладені в цій статті, забезпечить навантаженню можливість працювати на великій потужності, і при цьому зберегти хороші характеристики і надійність. Розроблена схема дозволяє створити компасний пристрій експресного тестування сонячних батарей.

In this work, we present flexible broadband photodetectors (PDs) fabricated by a deposition of nanostructured zinc oxide (ZnO) films on polyimide (PI) substrates by using cheap and scalable aqueous method Successive Ionic Layer Adsorption and Reaction (SILAR). In order to increase the long-wavelength absorption of the nanostructured ZnO layer, we created its intrinsic defects, including oxygen vacancies by post-treatment at 300 degrees C in vacuum and thus the light-sensitive material ZnO/PI was obtained. Then we applied silver nanoparticles (Ag NPs) from a silver sol onto a nanostructured ZnO film, which were visualized using SEM in the form of spheres up to 100 nm in size that increased the photocurrent and figures of merit of thus obtained light-sensitive material ZnO_Ag/PI due to localized surface plasmon resonance and double Schottky barriers at the Ag-ZnO interface. To fabricate photodetectors based on a photoconductive effect, these ZnO/PI and ZnO_Ag/PI materials were equipped with ohmic aluminum contacts. The spectral responsivity (R-lambda up to 275 A/W to UV light) of solution-processed flexible broadband photodetector based on ZnO_Ag/PI material at different wavelengths of light and light power densities is better than R-lambda of the ZnO/PI photodetector, and at least an order of magnitude higher than R-lambda of photodetectors based on nanostructured zinc oxide described in recent articles. The external quantum efficiency (EQE) of both PDs in this study in UV-Vis-NIR spectra is very high in the range from 1 center dot 10(2) to 9 center dot 10(4) % and is better or of the same order of magnitude as the EQE data of modern flexible broadband high-sensitivity PDs based on nanostructured heterostructures containing ZnO. The specific detectivity in UV-Vis-NIR spectra is large for ZnO/PI (from 3.5 center dot 10(10) to 1 center dot 10(12) Jones) and especially for ZnO_Ag/PI (from 1.6 center dot 10(11) to 8.6 center dot 10(13) Jones), which indicates the ability of the PDs based on light-sensitive materials ZnO/PI and ZnO_Ag/PI to recognize a very weak light signal.

In the article analytical and field test of the experimental photovoltaic station equipped with hybrid photovoltaic module equipped and innovative power take-off system with DC-DC converters was carried out. It was established that the power take-off system with DC-DC converters working with hybrid photovoltaic modules has an efficiency up to 92.5 % in a wide range of solar radiation intensity, and was confirmed reliability and effective working of hybrid photovoltaic modules innovative components. It has been shown that experimental sample of the optimized photovoltaic station with a low concentration of solar radiation can generate in stable mode values of electric power on a level of 14 kW.

In this work, we used the low temperature solution growth Successive Ionic Layer Adsorption and Reaction (SILAR) for a deposition of the nanostructured undoped and indium doped (ZnO and ZnO:In) thin films on flexible polyimide (PI) substrates for their use as cheap non-toxic thermoelectric materials in the flexible thermoelectric modules of planar type to power up portable and wearable electronics and miniature devices. The use of a zincate solution in the SILAR method allows to obtain ZnO:In film, which after post-growth annealing at 300 degrees C has low resistivity rho approximate to 0.02 Omega m, and high Seebeck coefficient-147 mu V/K and thermoelectric power factor similar to 1 mu W K-2 m(-1) at near-room temperatures. As evidence of the operability of the manufactured films as the basis of the TE device, we have designed and tested experimental lightweight thin-film thermoelectric module. This TE module is able to produce specific output power 0.8 mu W/m(2) at Delta T = 50 K.

Possibilities of increasing the efficiency by more than 20 % for silicon photoelectric converters made in China have been investigated.It has been established by the method of computer simulation that the lifetimes of nonequilibrium charge carriers, which are 520 s, realized in such photoelectric converters, do not limit the possibility of increasing their efficiency by more than 20 %.It has been shown that an increase in the photocurrent density to 43.1 mA/cm 2 leads to an increase in the efficiency to 20.1 %, and a decrease in the diode saturation current density to 3.1•10 -14 A/cm 2 leads to an increase in the efficiency to 20.4 %.Simultaneous change of these diode characteristics leads to an increase in the efficiency to 23.1 %.The paper proposes physical and technological approaches to increase the photocurrent density and reduce the diode saturation current density in ready-made photovoltaic converters.The study of the influence of operating temperature on the efficiency of crystalline silicon photoelectric converters has been carried out in the article.It has been shown that with increasing operating temperature the relative decrease in the efficiency of single-crystal devices is -0.7 relative %/C, which is significantly higher than in the device structures of European production and due to non-traditional decrease in short-circuit current density.Mathematical modeling of the influence of light-emitting diode characteristics on the efficiency of crystalline silicon solar cells showed that a decrease in the efficiency of device structures with increasing operating temperature is due not only to an increase in diode saturation current density from 10 -13 to 3•10 -13 A, which is 300 %, but also by reducing the shunt resistance from 2.5 to 1.5 kOhm.A study of the effect of operating temperature on the diode saturation current showed that the height of the potential barrier in the studied silicon photovoltaic converters is 0.87 eV due to the insufficient level of doping of the base material.The limited height of the potential barrier leads to an unconventional decrease in the shunt resistance with increasing operating temperature.

The subject matter of study in the article is the optical, dielectric and photodielectric properties of ZnSe crystals containing macroscopic structural inhomogeneities. The goal of this work is to study large-scale inhomogeneities in ZnSe crystals, which is important for determining the suitability of their application in technology. The tasks to be solved are: in a crystalline ZnSe ingot of cylindrical shape in the optical range at perpendicular to the light flux orientation of the sample axis to detect macroscopic inhomogeneities and establish their relationship with the features of the dielectric properties of the local regions of the ZnSe ingot; to investigate the influence of nonmonochromatic light flux on the distribution of dielectric parameters along the axis of the ZnSe ingot containing areas of macroscopic inhomogeneities. The problems were solved by the following methods: the homogeneity of the zinc selenide ingot was studied by the polarization-optical photoelasticity method; the photometry method was used to study the intensity distribution of the light scattered by the sample perpendicular to its axis; the dielectric properties of a crystalline ZnSe ingot were investigated by the capacitive method. The following results were obtained. In ZnSe crystals regions of three types were found: isotropic, weakly anisotropic, and anisotropic. Sharp changes in the intensity of scattered light are observed in the region of large-scale optical inhomogeneity, and light scattering in this region occurs anisotropically. The angular dependences of C and tgδ at an electric field frequency of 1 kHz are obtained for the region of large-scale optical anisotropy. The changes in dielectric parameters under the action of nonmonochromatic light along the sample axis are measured. Conclusions. It was found that ZnSe crystals are characterized by large-scale inhomogeneities of the investigated properties. A close relationship is noted between the optical and electrophysical properties, which is probably due to the mutual influence of two-dimensional and point defects on the formation of a defect structure during the growth and further cooling of the crystal.

The subject matter of study in the article is the optical, dielectric and photodielectric properties of ZnSe crystals containing macroscopic structural inhomogeneities. The goal of this work is to study large-scale inhomogeneities in ZnSe crystals, which is important for determining the suitability of their application in technology. The tasks to be solved are: in a crystalline ZnSe ingot of cylindrical shape in the optical range at perpendicular to the light flux orientation of the sample axis to detect macroscopic inhomogeneities and establish their relationship with the features of the dielectric properties of the local regions of the ZnSe ingot; to investigate the influence of nonmonochromatic light flux on the distribution of dielectric parameters along the axis of the ZnSe ingot containing areas of macroscopic inhomogeneities. The problems were solved by the following methods: the homogeneity of the zinc selenide ingot was studied by the polarization-optical photoelasticity method; the photometry method was used to study the intensity distribution of the light scattered by the sample perpendicular to its axis; the dielectric properties of a crystalline ZnSe ingot were investigated by the capacitive method. The following results were obtained. In ZnSe crystals regions of three types were found: isotropic, weakly anisotropic, and anisotropic. Sharp changes in the intensity of scattered light are observed in the region of large-scale optical inhomogeneity, and light scattering in this region occurs anisotropically. The angular dependences of C and tgδ at an electric field frequency of 1 kHz are obtained for the region of large-scale optical anisotropy. The changes in dielectric parameters under the action of nonmonochromatic light along the sample axis are measured. Conclusions. It was found that ZnSe crystals are characterized by large-scale inhomogeneities of the investigated properties. A close relationship is noted between the optical and electrophysical properties, which is probably due to the mutual influence of two-dimensional and point defects on the formation of a defect structure during the growth and further cooling of the crystal.

For large-scale GaAs-based solar cells using, it is necessary to increase their efficiency and reduce the cost of their manufacture.The existing model, which describes the processes in the semiconductor material, has significant simplifications and does not take into account a number of significant processes.The article considers the problem of processes in gallium arsenide based solar cells optimization, proposes to take into account the mechanisms of radiation, surface recombination, which have a significant impact and have not been previously considered in the physical model.The article also considers methods for taking into account the photon reabsorption, the effect of which in GaAs based solar cells is taken into account by building a model of photon reabsorption.The proposed model is based on the Steiner photon absorption model, which is successfully used for modeling single-junction GaAs solar cells, taking into account some boundary conditions considering recombination processes on the device inner surfaces.Calculations using the proposed model allowed us to offer an optimized solution of thin GaAs based solar cells with a good back surface mirror and reduced surface recombination.

Systems based on the charging line are one of the most suitable designs of electromagnetic pulses generators for building up test lines of electronic devices. Such cable-based charging lines in combine with fast switching triggers will allow generating electromagnetic impulses with nanosecond duration and rising time at a level of 1 nanosecond. The amplitude of impulse directly depends from the cable charge voltage and equal half of its value. Therefore, control and setting up of generator with such parameters are quite difficult task. In present work this problem was solved by design microcontroller based electronic devices stress testing system, which includes control and power supply units for charging line generator. By using microcontroller as a control center we concentrate in one device the possibility to charge line in the range from 40 to 400 V with steps no more than 1 V, realize like manual start of a single pulse and automatic controlled regime with series of impulses and ensures necessary for safety indications of device working regimes.

In this work we investigate crystal structure, morphology, and composition of Cut films produced in different modes of SILAR on glass plates and on flexible poly(ethylene terephthalate) (PET) substrates in connection with their transport properties, and with electrical and thermoelectric properties as a whole. Temperature dependences of resistivity for most Cut films have the crossover from semiconducting to metallic behavior with increasing temperature. The semiconductor carrier transport occurs in Cut films through nearest neighboring hopping. Metallic transport in Cut films carried out in accordance with the ionized impurity scattering and the carrier-carrier scattering model.