Charged Device Research Articles

The Influence of Donor/Acceptor Interfaces on Organic Solar Cells Efficiency and Stability Revealed through Theoretical Calculations and Morphology Characterizations.

End-groups halogenation strategies, generally refers to fluorination and chlorination, have been confirmed as simple and efficient methods to regulate the photoelectric performance of non-fullerene acceptors (NFAs), but a controversy over which one is better has existed for a long time. Here, two novel NFAs, C9N3-4F and C9N3-4Cl, featured with different end-groups were successfully synthesized and blended with two renowned donors, D18 and PM6, featured with different electron-withdrawing units. Detailed theoretical calculations and morphology characterizations of the interface structures indicate NFAs based on different end-groups possess different binding energy and miscibility with donors, which shows an obvious influence on phase-separation morphology, charge transport behavior and device performance. After verified by other three pairs of reported NFAs, a universal conclusion obtained as the devices based on D18 with fluorination-end-groups-based NFAs and PM6 with chlorination-end-groups-based NFAs generally show excellent efficiencies, high fill factors and stability. Finally, the devices based on D18: C9N3-4F and PM6: C9N3-4Cl yield outstanding efficiency of 18.53 % and 18.00 %, respectively. Suitably selecting donor and regulating donor/acceptor interface can accurately present the photoelectric conversion ability of a novel NFAs, which points out the way for further molecular design and selection for high-performance and stable organic solar cells.

A Novel Portable Solar Powered Wireless Charging Device

This paper presents the development of a portable solar panel wireless charging device with an advanced charging algorithm. The device features a 6500 mAh Li-ion battery and is designed to efficiently charge smartphones and laptops. It incorporates a simulated solar panel, charging circuit, microcontroller, and wireless charging circuits. Rigorous testing has demonstrated its stable output voltage and current at 5 V/2 A, with high power transfer efficiency. The advanced charging algorithm optimizes power transfer efficiency and reduces charging time by adjusting the current and voltage to match the device’s needs. This smart approach extends battery life and improves device performance. The device utilizes the Basic MPPT P&O Algorithm to dynamically track the solar panel’s Maximum Power Point and optimize power extraction. The Lithium Battery Charging Characteristic Algorithm adjusts the charging levels to ensure safe and efficient charging. However, challenges were encountered during implementation and testing, highlighting the complexities of real-world scenarios and the need for further optimization. The device offers a sustainable and environmentally friendly charging alternative, particularly in areas with limited power access. The research findings contribute to the field of wireless charging, driving advancements in sustainable and efficient technologies.

Optimizing Energy Transfer: A Novel Wireless Bypass Charging System for E-Vehicles with Darrieus Technology

This paper presents a parallel resonant inverter-based solution to power several distributed transmitter coils after giving a summary of the available electric vehicle (EV) charging technologies. Where the receiver coil is attached to the car determines which coils are energized in sequence. By means of this approach, Inductive Power Transfer (IPT) Technology functions. Ingenious magnetic induction bypass charging does away with the need for actual connections between the charger and the charging device. Convenient and easy charging of the smartphone is made possible by the charging station's use of magnetic induction. This method uses electromagnetic fields to help the energy transfer between coils placed in the receiving device and the charging station. Close to the charging station, the device's coils oscillate at the same frequency. An electrical current is therefore generated and sent through the receiver coil, so replenishing the device's battery. Offering consumers an easy and practical way to charge their gadgets without the need for cables or plugs is the aim of wireless bypass charging. By enhancing device portability, convenience, and efficiency in the powering process, this invention has the potential to completely transform a number of industries, including consumer electronics, healthcare, and automotive.

Revealing the impact of thermal annealing on the perovskite/organic bulk heterojunction interface in photovoltaic devices.

Perovskite/organic bulk heterojunction (BHJ) integrated solar cells have tremendous development potential to exceed the Shockley-Queisser limit efficiency of single-junction photovoltaics, due to the merits of spectra response extension. However, the presence of energy level barriers and severe non-radiative recombination at the interface between perovskite and BHJ greatly hindered the transport and collection of charge carriers, usually leading to large Voc and photocurrent loss, as well as the stability degradation of integrated devices. Therefore, investigating the interface properties of perovskite/BHJ is crucial for understanding the charge transport process and enhancing device performance. In this study, we effectively regulated the interface properties and charge transport in perovskite/BHJ integrated devices using a thermal annealing process. Using Kelvin probe microscopy, photoluminescence, and transient absorption spectroscopy, we revealed that moderate annealing treatment would contribute to forming close interface contact and provide more channels or pathways for charge transfer, which is advantageous for the interface charge collection and device performance. In addition, the lone pair electrons of acyl, thiophene and pyrrole function groups in polymer PDPP3T and PCBM can act as the Lewis base and provide electrons to the under-coordinated lead atoms or clusters in the perovskite, effectively passivating traps on the surface and grain boundaries of the perovskite through Lewis acid-base coordination. Finally, we improved the photovoltaic conversion efficiency of the device to 21.57% with enhanced stability using an optimized thermal annealing process. This study provides a comprehensive understanding of the integrated perovskite/BHJ interface properties, which could be extended to other optoelectronic devices based on a similar integrated structure.

A compact dielectric grating-based charged particle bunch length diagnostic device at ARES

Dielectric gratings are already used in Dielectric Laser Acceleration due to their high damage thresholds at high acceleration gradients. When an electron bunch passes close to one of these gratings, it emits radiation, and the features of this radiation will be dependent upon the beam position relative to the grating, the bunch charge, and the bunch length. A compact high-resolution diagnostics device will be developed that consists of multiple gratings with different periods; these types of devices are required for the accurate operation of future compact accelerators which are currently undergoing development and testing. ARES linac at DESY is able to provide sub-fs electron bunches and has a range of high-resolution diagnostic devices installed, such as the PolariX Transverse Deflecting Structure, which will allow for performance verification of a new diagnostic. The electron bunches can be altered, allowing for the measurement and analysis of the emitted radiation for different bunch lengths and charges. This work will present the current progress in this area, including the presentation and discussion of simulations, and a discussion of the planned experiments at ARES.

Morphology optimization via pre-aggregation and miscibility matching in PM6:L8-BO ternary organic solar cells.

To elucidate the mechanism by which pre-aggregation and miscibility matching govern the active layer morphology in non-fullerene organic solar cells, chloroform (CF) and o-xylene (OX) were used as solvents, while D18 and N2200 were incorporated as third components into the PM6:L8-BO system. The incorporation of D18 enhanced device performance, whereas the addition of N2200 reduced device performance. Based on surface energy analysis, the free energies of pure components and binary blends in different solvents were calculated, showing that the Gibbs free energies of D18, PM6 and L8-BO exhibited better pre-aggregation matching. Employing the melting point depression method, the Flory-Huggins interaction parameters of D18 : L8-BO (1 : 6) and N2200 : L8-BO (1 : 5) blends were calculated. The results revealed that the miscibility of the samples cast with CF was superior to those cast with OX. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) observations revealed that D18 could induce L8-BO to aggregate and crystallize to form a nanofiber architecture, leading to an optimized phase separation. Attributing to the desirable miscibility of D18 with L8-BO, the D18:L8-BO nanostructures could be dispersed within an amorphous PM6 matrix, forming a double-fibril network morphology that facilitated charge transfer and enhanced device performance. In contrast, N2200 was immiscible with L8-BO, which led to the formation of a suboptimal morphology exhibiting excessive aggregation or excessive dispersion, resulting in a deterioration in charge transfer and device performance. The investigation of pre-aggregation matching in solvents, and miscibility matching of the components could provide guidance for the rational selection of appropriate solvents and suitable third components towards high-performance ternary organic solar cells.

Development of a Portable SF6/N2 Mixed Gas Charging Device for On-Site Modification of Gas Insulated Current Transformer

Development of a Portable SF₆/N₂ Mixed Gas Charging Device for On-Site Modification of Gas Insulated Current Transformer

Modeling the operation of an induction charger for mobile charging of electric vehicles

The speed of implementation of electric vehicles depends on the level of development of the charging infrastructure, which is subject to ever new requirements, including increasing ease of use and reducing charging time. A solution to the problem could be an introduction of wireless charging of electric vehicles (inductive charging device – WPT). However, in order to produce an effective WPT (without preliminary calculation and modeling the efficiency of the device may not reach 10 %), it is necessary to select the parameters of the coils and simulate the frequency characteristics of the voltage. For this purpose, as part of the implementation of the project to create a mobile charging installation for electric vehicles, the problem of modeling the operation of the WPT has been solved. In accordance with the technical specifications, a coil has been built in Excel, which was used as geometry in Comsol to evaluate the distribution of magnetic fields. To study the frequency characteristics, the CST Studio program has been used. Using these programs, we simulated various methods for implementing the WPT with obtaining frequency characteristics. It has been confirmed that the coupling coefficient increases with decreasing distance between parts of the WPT. Calculations of resonant circuits and the expected efficiency for both types of resonant circuits have been carried out, and it has been concluded that decreasing the distance leads to a decrease in the resonant frequency of the system of connected circuits. The developed model allows us to obtain the values of the circuit capacitances for the formation of resonance, move on to practical implementation and verify the resulting models.

Structural Tailoring the Phenylenediamine Isomers to Obtain 2D Dion–Jacobson Tin Perovskite Solar Cells with Record Efficiency

Abstract2D Dion–Jacobson (DJ) tin halide perovskite shows impressive stability by introducing diamine organic spacer. However, due to the dielectric confinement and uncontrollable crystallization process, 2D DJ perovskite usually exhibits large exciton binding energy and poor film quality, resulting in unfavorable charge dissociation, carrier transport and device performance. Here, the ortho‐, meta‐, and para‐isomers of phenylenediamine (PDA) are designed for 2D DJ tin halide perovskites. Theoretical simulation and experimental characterizations demonstrate that compared with p‐PDA and m‐PDA, o‐PDA shows larger dipole moment, which further reduces the exciton binding energy for the 2D perovskites. Besides, there is a strong hydrogen bond interaction between o‐PDA cation and inorganic octahedron, which not only improves the structural stability, but also induces larger aggregates in the precursor to form dense and uniform high‐quality films, and strengthens the antioxidant barrier. More interestingly, femtosecond transient absorption further proves that o‐PDA organic spacers can reduce unfavorable small n‐phases, resulting in sufficient and effective charge transfer between different n‐value. As a result, the 2D DJ (o‐PDA)FA3Sn4I13 solar cells achieve a record power conversion efficiency of 7.18%. The study furnishes an effective method to optimize the carrier transport and device performance by tailoring the chemical structure of organic spacers.

Mitigation of PQ issues in EV charging station connected distribution system using novel RSMLI-based shunt APF

<span>In the present scenario, the significant use of electric vehicles (EVs) is growing rapidly in the automotive industry due to cheaper transportation, no fossil fuel required, low maintenance, no fuel cost, and low impacts on the environment over the formal internal combustion engine (ICE) vehicles. In actuality, these EVs are powered by batteries that are charged by a utility-grid-based charging facility. A power-electronic conversion-based charging device is used in this charging station to charge the battery packs in the EV system. The problem statement of this work is identified, these conversion devices in charging units proliferate the power quality of the utility grid. To overcome these problems, a classical square-wave inverter-based active power filter (APF) is employed. The major problems in classical inverters are high common-mode voltage, more harmonic profile, high dV/dt stress, high switching stress, and low efficiency. The contribution of this work is proposing the multilevel inverter (MLI) based APF for better compensation over classical inverters. In this approach, a novel reduced-switch MLI-based APF has been proposed for the mitigation of harmonic currents and also enhances the power factor in utility-grid-connected distribution systems. The effectiveness of the proposed reduced-switch multilevel inverter (RSMLI)-APF is validated by integrating the number of charging units with the MATLAB/Simulink tool, and simulation outcomes are shown along with comparisons.</span>

Fast Charging Control Method for Electric Vehicle-to-Vehicle Energy Interaction Devices

In order to reduce energy consumption and alleviate environmental pollution, the number of electric vehicles is increasing. But people are still worried about the choice of electric vehicles because of the problems of battery charging and duration. Therefore, a vehicle-to-vehicle energy interaction converter device is proposed in this paper, which has the characteristics of high-power, high-gain and small-volume. Based on the characteristics of this device, this paper uses modularized boost converter (MBC) to design this device. However, the electric vehicle battery can be divided into constant resistance loads and constant power loads (CPLs). Therein, the CPLs are very easy to cause the instability of the charging device. Therefore, a nonlinear controller combining an external nonlinear disturbance observer and an adaptive backstepping algorithm is proposed in this paper. In the first place, the high order MBC model is reduced to Brunovsky’s canonical form by using accurate feedback linearization technology in this paper. Afterwards, a nonlinear disturbance observer is designed to speed up the dynamic response of the system. At the same time, an adaptive backstepping controller is designed to ensure the stability of the output voltage in the sense of large signal by using the output of nonlinear disturbance observer. In the end, simulation and experiment results illustrate the correctness and feasibility of the converter device.

Performance assessment of an electrostatic filter-diverter stent cerebrovascular protection device. Is it possible not to use anticoagulants in atrial fibrilation elderly patients?

Stroke is the second leading cause of death worldwide. Nearly two-thirds of strokes are produced by cardioembolisms, and half of cardioembolic strokes are triggered by Atrial Fibrillation (AF), the most common type of arrhythmia. A more recent cause of cardioembolisms is Transcatheter Aortic Valve Replacements (TAVRs), which may onset post-procedural adverse events such as stroke and Silent Brain Infarcts (SBIs), for which no definitive treatment exists, and which will only get worse as TAVRs are implanted in younger and lower risk patients. It is well known that some specific characteristics of elderly patients may lower the safety and efficacy of anticoagulation therapy, making it a real urgency to find alternative therapies. We propose a device consisting of a strut structure placed at the base of the treated artery to model the potential risk of cerebral embolisms caused by dislodged debris of varying sizes. This work analyzes a design based on a patented medical device, intended to block cardioembolisms from entering the cerebrovascular system, with a particular focus on AF, and potentially TAVR patients. The study has been carried out in two stages. Both of them based on computational fluid dynamics (CFD) coupled with Lagrangian particle tracking method. The first stage of the work evaluates a variety of strut thicknesses and inter-strut spacings, contrasting with the device-free baseline geometry. The analysis is carried out by imposing flowrate waveforms characteristic of both healthy and AF patients. Boundary conditions are calibrated to reproduce physiological flowrates and pressures in a patient's aortic arch. In the second stage, the optimal geometric design from the first stage was employed, with the addition of lateral struts to prevent the filtration of particles and electronegatively charged strut surfaces, studying the effect of electrical forces on the clots if they are considered charged. Flowrate boundary conditions were used to emulate both healthy and AF conditions. Results from numerical simulations coming form the first stage indicate that the device blocks particles of sizes larger than the inter-strut spacing. It was found that lateral strut space had the highest impact on efficacy. Based on the results of the second stage, deploying the electronegatively charged device in all three aortic arch arteries, the number of particles entering these arteries was reduced on average by 62.6% and 51.2%, for the healthy and diseased models respectively, matching or surpassing current oral anticoagulant efficacy. In conclusion, the device demonstrated a two-fold mechanism for filtering emboli: while the smallest particles are deflected by electrostatic repulsion, avoiding microembolisms, which could lead to cognitive impairment, the largest ones are mechanically filtered since they cannot fit in between the struts, effectively blocking the full range of particle sizes analyzed in this study. The device presented in this manuscript offers an anticoagulant-free method to prevent stroke and SBIs, imperative given the growing population of AF and elderly patients.

Electroviscous effects in pressure-driven flow of electrolyte liquid through an asymmetrically charged non-uniform microfluidic device

BackgroundMicro-scale systems depict a different flow behavior from the macro-scale systems due to more vital surface forces such as surface tension, electrical charges, magnetic field, etc., which significantly affect the micro-scale flow. Further, among others, electrokinetic phenomena play a significant role at the micro-scale for controlling practical microfluidic applications. Therefore, it is essential to understand the fluid dynamics in micron-sized channels to develop efficient and reliable microfluidic devices. MethodsThe electroviscous effects in pressure-driven flow of electrolyte liquid through an asymmetrically charged contraction-expansion (4:1:4) slit microfluidic device have been investigated numerically. The mathematical model (i.e., Poisson's, Navier-Stokes, and Nernst-Planck equations) is solved using the finite element method to obtain the electrical potential, velocity, pressure, ion concentration fields, excess charge, an induced electric field strength for the following ranges of parameters: Reynolds number (Re=0.01), Schmidt number (Sc=1000), inverse Debye length (2≤K≤20), top wall surface charge density (4≤St≤16), surface charge density ratio (0≤Sr≤2) and contraction ratio (dc=0.25). Significant FindingsResults show that the charge asymmetry (Sr) at the different walls of the microfluidic device plays a significant role on the induced electric field development and microfluidic hydrodynamics. The total potential (|ΔU|) and pressure drop (|ΔP|) maximally increase by 197.45% and 25.46%, respectively with asymmetry of the charge. The electroviscous correction factor (ratio of apparent to physical viscosity) maximally changes by 20.85% (at K=2, St=16 for 0≤Sr≤2), 34.16% (at St=16, Sr=2 for 2≤K≤20), and 39.13% (at K=2, Sr=2 for 0≤St≤16). Thus, charge asymmetry (0≤Sr≤2) remarkably influences the fluid flow in the microfluidic devices, which is used for controlling the microfluidic processes, such as, mixing efficiency, heat, and mass transfer rates. Further, a simpler analytical model is developed to predict the pressure drop in electroviscous flow considering asymmetrically charged surface, based on the Poiseuille flow in the individual uniform sections and pressure losses due to orifice, estimates the pressure drop 1–2% within the numerical results. The robustness of this model enables the use of present numerical results for design aspects in the microfluidic applications.

A Deep Transfer Learning-Based Network for Diagnosing Minor Faults in the Production of Wireless Chargers

Wireless charger production is critical to energy storage, and effective fault diagnosis of bearings and gears is essential to ensure wireless charging performance with high efficiency, high tolerance to misalignment, and thermal safety. As minor faults are usually difficult to detect, timely diagnosis and detection of minor faults can prevent the fault from worsening and ensure the safety of wireless charging systems. Diagnosing minor faults in bearings and gears with data is a useful but difficult task. To achieve a satisfactory diagnosis of minor faults in the production of wireless charging systems related to the mechanical system that produces wireless charging devices, such as robot arms, this paper proposes a deep learning network based on CNN and LSTM (DTLCL). The method uses deep learning network, model-based transfer learning and range adaptation technology. First, a deep neural network is built to extract significant fault features. Second, the deep transfer network is initialised using model-based transfer learning with a good starting point. Finally, range adaptation using the maximum mean discrepancy between the features learned from the source and target ranges is realised by a multi-layer adaptive technology. The effectiveness of the method was verified using actual measurement data. The training time is 19 s, and the accuracy exceeds 94.5%. The explanation results show that the proposed DTLCL method provides higher accuracy and robust identification of smaller errors compared to the current combination of integrated and single non-transmission models. Due to its data-driven nature, the DTLCL method could be used for fault diagnosis of bearings and gears, which would further promote the application process of wireless charging.

Comparative Study of TiO2, ZnO, and Nb2O5 Photoanodes for Nitro-Substituted Naphthoquinone Photosensitizer-Based Solar Cells.

This research focuses on the first demonstration of NO2Lw (2-hydroxy-3-nitronaphthalene-1,4-dione) as a photosensitizer and TiO2, ZnO, and Nb2O5 as photoanode materials for dye-sensitized solar cells (DSSCs). The metal-free organic photosensitizer (i.e., nitro-group-substituted naphthoquinone, NO2Lw) was synthesized for this purpose. As a photoanode material, metal oxides, such as TiO2, ZnO, and Nb2O5, were selected. The synthesized NO2Lw contains an electron-withdrawing group (-NO2) and anchoring groups (-OH) that exhibit absorption in the visible range. The UV-visible absorbance spectrum of NO2Lw demonstrates the absorption ascribed to ultraviolet and visible region charge transfer. The NO2Lw interacts with the TiO2, ZnO, and Nb2O5 photoanode, as shown by bathochromic shifts in wavelengths in the photosensitizer-loaded TiO2, ZnO, and Nb2O5 photoanodes. FT-IR analysis also studied the bonding interaction between NO2Lw and TiO2, ZnO, and Nb2O5 photoanode material. The TiO2, ZnO, and Nb2O5 photoanodes loaded with NO2Lw exhibit a shift in the wavenumber of the functional groups, indicating that these groups were involved in loading the NO2Lw photosensitizer. The amount of photosensitizer loading was calculated, showing that TiO2 has higher loading than ZnO and Nb2O5 photoanodes; this factor may constitute an increased JSC value of the TiO2 photoanode. The device performance is compared using photocurrent-voltage (J-V) curves; electrochemical impedance spectroscopy (EIS) measurement examines the device's charge transport. The TiO2 photoanode showed higher performance than the ZnO and Nb2O5 photoanodes in terms of photoelectrochemical properties. When compared to ZnO and Nb2O5 photoanodes-based DSSCs, the TiO2 photoanode Bode plot shows a signature frequency peak corresponding to electron recombination rate toward the low-frequency region, showing that TiO2 has a greater electron lifetime than ZnO and Nb2O5 photoanodes based DSSCs.

Leading the Charge

As the demand for wireless charging devices in consumer electronics surges, CET&D explores the testing, standards and regulatory landscape for this emerging technology.

ПІДХІД ТА ВИМОГИ ДО СТВОРЕННЯ ЗАРЯДНОЇ ІНФРАСТРУКТУРИ В КИЄВІ ТА КИЇВСЬКІЙ ОБЛАСТІ

The article shows two different approaches to the development of charging infrastructure. The first ap-proach of expanding charging network proposes an average use of the charging point of about 5 percent. This approach focuses on the rapid creation of slow AC charging points (5-22 kW). However, low network utilization is not economically viable in the long term and limits investment by private companies. The second approach to network development is more usage-oriented, where charging points should be used with-in 15%. Also, the difference is fast charging with direct current (50-300 kW). Such a network develops more slowly, being restricted to major transport corridors; but in the future it looks more attractive, and this approach is currently domi-nant in the countries of the European Union. Methodology. The article uses the approach of comparing two ways of deploying the charging infrastructure at dif-ferent loads of one charging point and different power of the charging device. Goal. Possible creation of a charging network under the conditions of an acceptable load of one charging point. Originality. The article proposes an approach that allows using a charging station as a tool for increasing the de-mand for electric vehicles. Practical value. Existing legislation of the European Union on increasing environmental safety of vehicles, pro-vides possible background for installing chargers within the largest roads of the Kyiv region. It is necessary, because number of electric vehicles could stay low without charging infrastructure available. Keywords: motor vehicle, electric vehicle, charging point, charging infrastructure, location of charging station, power of charging point, the cost of connecting a charging station.

Photo-assisted capacitive performance of V2O5 supercapacitor

A photo-assisted energy storage system enables a new pathway to utilize unlimited solar energy. Herein, V2O5 was synthesized using a simple, time-saving thermal decomposition process. The V2O5 samples were characterized thoroughly. The photo-electrochemical performances of the as-prepared V2O5 samples were evaluated using a three-electrode system. The material showed increased specific capacity from 45 C g−1 to 69 C g−1 in the presence of light. The photo-assisted V2O5||V2O5 and V2O5||AC (activated carbon) ASC (asymetric supercapacitors) FTO devices effectively responded to the light sources. The areal capacity of the V2O5||AC ASC FTO photo-assisted charging device was 112 mC cm−2 under the given light intensity, whereas the device tested using the conventional process (without light irradiation) delivered only 45 mC cm−2 at the same current density. Further, the asymmetric FTO device delivered high specific energy and power density of 9.8 Wh kg−1, and 29 W kg−1 respectively, in the presence of light. Notably, the symmetric FTO device was photo charged to 200 mV in 1 h without any external current and was discharged in the dark at 0.01 mA cm−2. On the other hand, V2O5 symmetric coin cell delivered excellent cycle stability over 40,000 cycles at different current rates with an outstanding coulombic efficiency of 98%. These results are a clear indication that the photo charging-based supercapacitor will pave an innovative path in constructing futuristic energy storage devices.

Maximize Lifetime of Wireless Rechargeable Sensor Networks with Mobile Energy-Limited Charging Device.

Mobile charging devices (MCDs) have been regarded as a promising way to solve the energy shortage of wireless sensor networks. Due to ignoring some important factors, such as redundant sensor nodes, there is still room to improve network lifetimes. We propose a charging strategy for wireless sensor networks with one energy-limited MCD. To give the best support for sensor nodes which need charging the most, an algorithm is proposed to find the minimum sensor nodes which keep the coverage and connectivity of the network and have the least energy requirements. Then, the goal of maximizing network lifetime is changed into how to utilize the limited energy of the MCD to guarantee the minimum sensor nodes work as long as possible. If the MCD has enough energy for all sensor nodes, the charging algorithm is designed to minimize the outage time of the network and maximize charging efficiency. Otherwise, if the energy capacity is larger than the least energy requirement, the charging target minimizes the outage time of the minimum sensor node; otherwise the charging problem becomes maximizing the lifetime of minimum sensor nodes, which has lower complexity. The results of simulation experiments confirm that our scheme prolongs network lifetime and improves charging efficiency.

Selection of the Winding Type of Solid-State Transformers in Terms of Transmitting the Greatest Possible Power in the Frequency Range from 500 Hz to 6000 Hz

Solid-state transformer (SST) is an emerging technology that integrates with transformer power electronics converters and control. The most noticeable advantages of SST are the size and weight reduction compared with low-frequency transformers. Since this device is used in many devices such as smart grids, traction systems, systems with renewable energy sources (RESs) and electric vehicle charging devices, it is important to build a high-efficiency device at a low cost. The article evaluates a medium frequency transformer (SST) operating at a frequency of 500 Hz to 6000 Hz with coils wound with aluminum foil or Litz windings and of a grain-oriented electrical steel (GOES) core. The calculations were made using the 3D field method using the numerical finite element method, and the results were compared with the tests of the real model. The measurement method based on the Fourier analysis of real signals was used for the research.