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Abstract This paper proposes an isolated single‐phase impedance‐source ac‐ac converter with a wide voltage conversion ratio and a safe commutation strategy. The new topology has noteworthy features like continuous input current, galvanic isolation, and non‐inverting and inverting buck‐boost modes with a wide voltage coverage. Also, only one switch operates with high‐frequency PWM signals, reducing the semiconductor switching loss. The galvanic isolation has been achieved by employing a high‐frequency transformer (HFT), eliminating low‐frequency transformers (LFT) from the topology. A safe commutation strategy has been designed and applied to the converter to mitigate the voltage and current spikes on power switches, which eliminates additional snubber circuits. A prototype has been designed to validate the suggested converter performance in stand‐alone and DVR applications. The peak obtained efficiency equals 96.1% and 94.9% in inverting and non‐inverting step‐down and step‐up modes, respectively, validated by an accurate power loss model and experimental results. Experimental results confirm the theory and operation of the proposed converter.

Abstract This paper introduces a new direct step‐up ac‐ac converter designed based on the SEPIC. It provides a higher step‐up conversion ratio than other counterparts with valuable features like high efficiency, reasonable input and output total harmonic distortions (THD), continuous input current waveform, common ground, few components, and single‐stage conversion without snubber and LC filters. Unlike most counterparts, the duty cycle can be varied between zero and one in boost operation and is not limited to any value below one. The voltage stress on one switch is reduced by increasing the winding coefficient of the utilized coupled inductor, and current stress on another is independent of this coefficient. It reduces the switches' losses and improves the converter efficiency. Thanks to the above attributes, the proposed converter is suitable for inductive power transfer from low‐voltage ac sources, operating as an ac voltage regulator for sensitive ac loads, and any applications that require a boost converter with few components. This article shows the converter's operation principle and evaluates its performance through experiments on a 225 W prototype. Accordingly, the maximum obtained efficiency is 95.4%. The input and output current THDs for the nominal inductive load equal 4.5 and 2.8%, respectively. Results confirm the claims.

Abstract This paper investigates the stability and reliability analysis of a non‐isolated high‐gain DC‐DC converter. The proposed DC‐DC converter produces a high gain output voltage with a lower duty ratio and reduced voltage stress on the semiconductor switch. A reliability analysis is performed to predict the failure rate and lifetime of the individual components using the military handbook (MIL‐HDBK‐217F). A state space equation and small signal modeling of the proposed converter are derived to elucidate the performance of the proposed converter through stability analysis. A closed‐loop using PID controller is incorporated to attain the constant regulated output voltage during sudden parameter changes. The validation of the closed‐loop using the PID controller is verified with the wide range of variations in the different parameters, such as input voltage, load value, and reference voltage value. The laboratory‐based prototype is developed for the proposed converter and validated the performance with 250 W. The power density and efficiency of the proposed converter are 1.360 kW/L and 93%, respectively.

With the increasing demand for high power density, and to meet extreme working conditions, research has been focused on investigating the performance of power electronics devices at cryogenic temperatures. The aim of this paper is to review the performance of power semiconductor devices, passive components, gate drivers, sensors, and eventually power electronics converters at cryogenic temperatures. By comparing the physical properties of semiconductor materials and the electrical performance of commercial power semiconductor devices, silicon carbide switches show obvious disadvantages due to the increased on-resistance and switching time at cryogenic temperature. In contrast, silicon and gallium nitride devices exhibit improved performance when temperature is decreased. The performance ceiling of power semiconductor devices can be influenced by gate drivers, within which the commercial alternatives show deteriorated performance at cryogenic temperature compared to room temperature. Moreover, options for voltage and current sense in cryogenic environments are justified. Based on the cryogenic performance of the various components afore-discussed, this paper ends by presenting an overview of the published converter, which are either partially or fully tested in a cryogenic environment.

The aircraft power supply system is the power source of all electrical equipment on board，thus its safety and reliability are pretty important. Against the backdrop of environmental protection and high-efficiency development needs，research and application of more/all electric aircraft technology with electric power as the core is advanced. The widespread use of electric drive devices and power electronic devices has led to the complexity of aircraft power supply system structure，which puts forward higher requirements for aircraft reliability，safety，testability and maintainability，so that researches on fault diagnosis technology for aircraft power supply systems are of great significance. In this paper，firstly the composition structure and respective functions of aircraft power supply system are introduced. Secondly，the development process of aircraft power supply system is outlined. Thirdly，the characteristics of typical domestic and foreign power supply systems are compared. Fourthly，the main failure modes，fault characteristics and failure causes of aircraft power supply system are summarized，and a design architecture of aircraft power health management system is proposed. Fifthly，the research progress of fault diagnosis methods based on model and data are reviewed，then，the characteristics of various diagnostic methods are evaluated from aspects such as accuracy，data demand，applicability and implementation difficulty. Finally，the challenges and development trends of fault diagnosis technology for aircraft power supply system are pointed out.

Abstract Interconnecting multiple microgrids (MGs) to form a MG cluster (MGC) is significant to improve the MG power supply reliability and increase the new energy accommodation capacity. However, for the traditional MGC in complex operational conditions, the following technologies need to be further researched, such as mutual power support among MGs, voltage support and power quality improvement and so on. Focusing on the above problems, a novel virtual synchronous port control (VSPC) strategy for MGC is proposed. Firstly, a multi‐port soft open point (SOP) is used to interconnect each sub‐MG in the MGC, to achieve a better flexible interconnection among sub‐MGs. Secondly, on this basis, the VSPC strategy is proposed. By adopting the DC voltage control of multi‐port SOP and the virtual synchronisation control of interconnecting ports, multiple voltage source converters (VSCs) are cluster controlled to provide the sub‐MGs with superordinate ports with virtual synchronisation characteristics, which ensures the dynamic balance of the power inside the MGC and achieves better voltage and frequency support capability. Finally, the example results verify the feasibility and effectiveness of the proposed VSPC strategy.

Abstract The electrification of remote islands has long been a subject of research interest, primarily because of their historical reliance on fossil fuels, leading to a significant carbon footprint. Recent advancements in wave energy converters offer a promising avenue to make these islands more self‐sustainable while considerably reducing carbon emissions. However, the persistent issue of voltage dips due to weaker grids continues to pose a challenge. This study introduces a multi‐mode converter control strategy with the goal of electrifying remote islands, employing a linear generator‐based wave energy converter in a unified electrical model. Various scenarios, including voltage dips and mainland grid disconnection, are simulated using MATLAB/Simulink. The study demonstrates the converter's ability to transition swiftly and smoothly in response to these scenarios, ensuring an uninterrupted power supply. Furthermore, the analysis indicates that the power quality at the point of common coupling remains well within acceptable standards.

The p-GaN-gated E-mode HEMTs (P-HEMTs) are being extensively studied for emerging power electronics. However, the devices still suffer from performance trade-off among threshold voltage (V TH), output drain current (I DS), and breakdown voltage (V BD). Herein, we propose a P-HEMT with a stair-like p-GaN cap layer to boost their performance. The p-GaN cap layer is composed of four discrete p-GaN staircases with the decreased thickness to the right (R ight- S tair P -HEMT) or to the left (L eft- S tair P -HEMT). It is found that the RSP-HEMT simultaneously achieves the 1.3 times increased I DS, 160 V enhanced V BD, and improved V TH stability against drain-induced barrier lowering effects, compared with the LSP-HEMT and the conventional B a S eline P -HEMT. These device merits should be attributed to the effective manipulation of the lateral electric field (E F) under all bias conditions by the unique band structures enabled by the RSP configuration. Such E F manipulation strategies offer us helpful guidance and insights to further propel the development of high-performance E-mode P-HEMTs. [ABSTRACT FROM AUTHOR]

Cell phones, tablets, laptop computers, and many other consumer technology gadgets use lithium-ion batteries (LIBs). The characteristics of lithium batteries include a high specific energy, great efficiency, and a long life. Owing to their distinctive qualities, lithium batteries are now the preferred power source for the electronics industry, with annual production in billions of units. This paper discusses several safety hazards introduced by mechanical, thermal, and electrical abuse as well as cutting-edge fixes for these difficulties. This review sought to achieve a deeper understanding of the safety risks of lithium-ion batteries depending on materials chemistry together with a positive response to these problems. This review discusses different methods for enhancing cell safety, including cooling, balancing, and cell chemistry. It then examines current safety regulations and associated testing procedures. Finally, it concludes with observations on potential future advancements and the prospects for safer lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

The quadratic buck converter is renowned for its steep step‐down capability. It encounters increased losses due to its high component count. In scenarios with light loads, switching losses become the dominant factor. Additionally, the presence of two right‐half plane zeros impairs transient response, even at high‐frequency switching operations. Incorporating this converter into the digital domain introduces an undesired phenomenon known as subharmonic oscillation, rendering the system unstable, albeit potentially mitigated over time—a drawback particularly undesirable for converters tasked with rapid load dynamics. This paper introduces an adaptive pulse skipping modulation scheme to control metal–oxide–semiconductor field‐effect transistor (MOSFET) switching actions, enhancing overall efficiency in discontinuous conduction mode. Furthermore, the effects of right half‐plane (RHP) zeros on stability are analyzed within these switching schemes. The proposed scheme is integrated with voltage‐mode control. Simulation and theoretical analyses are conducted to validate this converter. A flat efficiency of 89% to 86% for the load range of 25 to 700 mA is obtained, outperforming other existing schemes. The results demonstrate that the adaptive pulse modulation scheme effectively improves efficiency and stability in discontinuous conduction mode converters. This research provides valuable insights for optimizing power electronics systems with varying load dynamics. [ABSTRACT FROM AUTHOR]

Electrostatic energy storage capacitors are essential passive components for power electronics and prioritize dielectric ceramics over polymer counterparts due to their potential to operate more reliably at > 100 ˚C. Most work has focused on non‐linear dielectrics compositions in which polarization (P)/electric displacement (D) and maximum field (Emax) are optimized to give values of energy density, 6≤U≤21 J cm−3. In each case however, either saturation (dP/dE = 0, AFE) or "partial" saturation (dP/dE → 0, RFE) of P limits the value of U which can be achieved before breakdown. It is proposed that U can be further improved with respect to relaxors (RFEs) and anti‐ferroelectrics (AFEs) by designing high permittivity quasi‐linear dielectric (QLD) behaviour in which dP/dE remains constant up to ultrahigh Emax. QLD multilayer capacitor prototypes with dielectric layers composed of 0.88NaNb0.9Ta0.1O3‐0.10SrTiO3‐0.02La(Mg1/2Ti1/2)O3 deliver room temperature U ≈ 43.5 J cm−3, supporting an extremely‐large Emax ≈ 280 MV m−1, both of which exceed current state‐of‐art by a factor of two for devices based on powder, tape‐cast technology. Importantly QLD capacitors exhibit scant variation in U (≈15 J cm−3) up to > 200 ˚C and robust resistance to cyclic degradation, offering a promising new approach for the development of sustainable technology. [ABSTRACT FROM AUTHOR]

The presence of non-linear, time-variant loads in power networks introduces harmonics and other power quality issues in voltage and current waveforms. With the growing prevalence of power electronics, managing harmonic distortion has become a significant challenge in modern power distribution systems. This study aims to assess and analyze power quality at various locations within an academic institution (Sultan Qaboos University). The study encompasses the outputs of PV converters, uninterruptible power supplies (UPS), chillers with variable-speed motors, 11 kV/415 V transformers at both the College of Engineering and the Center of Information Systems, as well as two main substations supplying power to the university (33 kV/11 kV). Data collected—such as harmonic content in current and voltage waveforms and Total Harmonic Distortion (THD)—were meticulously analyzed to identify the factors affecting waveform quality. Measurements were conducted using advanced power quality instruments (Fluke 435-II), and the data were analyzed using MATLAB software. The study reveals that most results adhered to both the Oman grid code and international standards. The findings and methodology presented in this paper provide a critical benchmark for guiding standards compliance as Sultan Qaboos University, and other academic institution, undertakes the modernization of aging equipment and the expansion of new high-tech facilities. [ABSTRACT FROM AUTHOR]

This paper proposes a systematic approach to enhance the performance of a 21‐level asymmetrical multilevel inverter (MLI) with less power electronics switches and DC voltage sources. In the first step (Configuration 1), the voltage level is improved at the cost of DC‐link voltage utilization. In the second step (Configuration 2), the ratio of the DC‐link voltages is modified to improve the utilization of DC‐link voltage, with an insignificant reduction of voltage levels as compared to Configuration 1. Finally, another modification of the MLI configuration is proposed (Configuration 3), by incorporating an H‐bridge in place of a T‐type module for further improvement of DC source utilization and increasing the number of voltage levels. Thus, Configuration 3 improves the inverter's total standing voltage (TSV) and efficiency. To reduce the number of DC sources, the output voltage levels are obtained in Configuration 3 by adding and subtracting the input DC sources. Moreover, conducting switches are reduced to minimize conduction loss and maximize efficiency. The DS1103‐based digital controller is used to verify the performance of the proposed configurations, which are compared with the literature‐based MLI models. [ABSTRACT FROM AUTHOR]

The growing interest for power electronics devices demands suitable materials which can perform in harsh conditions. Gallium oxide (Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$) has shown tremendous potential in high voltage, high temperature, and gassensing applications due to its unique material properties. Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$ is considered to be the next‐generation material for power electronics owing to ultrawide bandgap of 4.5–4.9 eV and high electric field of 8 MV cm−1. These material properties coupled with high‐power figure of merits make Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$ a superior material compared to GaN and SiC. Herein, state‐of‐the‐art development and recent breakthroughs in Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$‐based field‐effect‐ transistors (FETs) highlighting major ongoing research are reviewed. The review describes the material property, band structure, and Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$‐based field‐effect transistors in detail. Some promising applications capitalizing the epitaxial growth techniques along with the characteristics and performance of Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$‐based devices are also explained. The prime objective of this review is to provide an up‐to‐date scientific framework pertaining to this niche emerging research area followed by device processing. This survey reveals the potential of Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$‐based FETs for high‐ voltage and high‐power applications while several critical challenges have to be still overcome. Finally, insights are represented and future perspectives of Ga2O3$\left(\text{Ga}\right)_{2} \left(\text{O}\right)_{3}$‐based transistors along with their hetero‐structures are discussed. [ABSTRACT FROM AUTHOR]

With the penetration of the high proportion of power electronics interfaced energy resources, the frequency stability issue in power systems is becoming increasingly prominent. This paper proposes a coordinated control strategy of multiple voltage source converter based high voltage direct current transmission (VSC‐HVDC) to simultaneously improve the transient frequency and steady‐state frequency after a severe disturbance. Firstly, a modified average system frequency response (MASFR) model is constructed with reserve power limitation, which takes into account the frequency responses of different types of generators (thermal, hydro and new energy resources). Secondly, according to the frequency stability requirements, the corresponding constraints, which consider the overload capacity of VSC‐HVDC, the AC transmission capacity and the frequency of AC grids on both sides of VSC‐HVDC, are formulated. Thirdly, for the transient frequency control, the coordinated optimization control model of multiple VSC‐HVDC is established, which aims to minimize the control energy considering the transient frequency threshold. For the steady‐state frequency control, the coordinated optimization control model is fomulated, which aims to minimize the control cost while considering the steady‐state frequency threshold. The two control schemes achieve seamless and smooth switching. Finally, the correctness and effectiveness of the proposed control strategy are verified in the improved IEEE 39 bus system. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive guide for the design and development of a power electronic converter, specifically focusing on the Buck converter. The guide aims to bridge the gap between theoretical knowledge and practical application, providing engineering students with a hands-on experience in digital control using the STM32 microcontroller. The workshop experience described covers all necessary steps, from the initial design and simulation using tools like MATLAB-Simulink and Plecs to the final implementation and testing of the converter. The educational value of this approach is highlighted, emphasizing the importance of practical engagement in understanding complex concepts related to power electronics. [ABSTRACT FROM AUTHOR]

Traditional valve-controlled hydraulic cylinders are usually very inefficient due to power loss through the control valve. An efficient alternative architecture is to distribute power electrically rather than hydraulically to a group of cylinders and drive each cylinder via individual servomotor-driven pumps. This arrangement is called electrohydrostatic actuation. Such actuators are currently available for power ratings of several hundred watts or greater, but not in the sub-100 W range. This paper details the design, simulation and testing of a piezopump which is intended to address this gap. The motivation is for aerospace applications, and in particular accessory actuators used in the landing gear system. The 10–100 W range is a high-power output for a piezopump, and to achieve this a novel design using disc-style reed valves was developed to allow pumping frequencies above 1 kHz. These high frequencies necessitated the development of custom power electronics capable of delivering 950 V peak-peak sine wave excitation to a largely capacitive load. Experimental results show that the piezopump is capable of delivering over 30 W of hydraulic power, and at no-load can deliver up to 2 L/min of flow at 1250 Hz. Future development includes a transition to multi-cylinder pumps, and improved reed-valve modelling to improve the accuracy of simulated performance. [ABSTRACT FROM AUTHOR]

Due to advances in power electronics technology and the evolution of automation devices, the number of electrical devices that are sensitive to power quality is rapidly increasing, and for this reason, users are increasing their demand for high quality. To meet power quality demands, many power conversion devices are used, including dynamic voltage restorers (DVRs). DVRs are recognized as devices that can effectively manage problems such as voltage segments, swells, and harmonics. DVR control requires many samples for harmonic compensation, which has the disadvantage of being complicated to implement due to fast digital signal processing computation and the application of the cyclic discrete Fourier transform. In this paper, a high-precision DVR system configuration is proposed that compensates for harmonics using a periodically equivalent time-interval sampling technique and a novel circular-structured memory filter. The proposed circular-structured multi-pointer memory filter is an effective filter algorithm for high-precision input voltage measurement because it can remove noise and compensate for the delay of the phase angle of the filter in voltage measurement. A simulation and DVR prototype system were built, and the feasibility and effectiveness of the phase angle multi-filter voltage detection method and the compensation method were verified by experiments. [ABSTRACT FROM AUTHOR]

Soft switching reduces voltage and current stress during transitions, smoothing and quieting operations and reducing electromagnetic interference while also increasing efficiency and equipment lifespan. Circuit design, component selection, and switching frequency optimization affect power electronics soft switching. This paper proposes boost integrated half-bridge dual-output series resonant (BIHBDOSR) converter, a novel converter design and control method to increase series resonant converter performance by reducing storage element size, switch count, and switching losses. This methodology relies on soft-switching technologies like zero-voltage switching (ZVS) and zero-current switching (ZCS). These methods use class-D, class-E, series, parallel, and series–parallel resonant converter circuits to increase efficiency and minimize component stress. The proposed converter is ideal for constant voltage, constant power, and current-controlled loads with the output voltage being regulated by a closed-loop PI controller. The output voltages for two loads in the simulation depart from reference values. V01 changes from 14 to 20 V and V02 from 18 to 15 V at 300 ms owing to switching variances. The proposed converter utilizes gate driver circuits, resonant tank circuit, current sensor, FPGA board for closed-loop control, and current sensor for stability, ensuring converter stability. The proposed converter closed-loop control method modifies PWM signals to regulate both loads independently and ensure steady output voltage. Additionally, to validate the effectiveness of proposed converter, a 50-W driver circuit is designed, delivering two independent outputs of 20 W and 30 W. Frequency modulation (FM) and duty cycle control methods are employed to obtain the desired outputs. [ABSTRACT FROM AUTHOR]

The study introduces a method for identifying the location of receiver coils within a multi‐transmitter IPT system that utilizes shared transmitter coils. In contrast to the conventional receiver coil position recognition methods, this approach eliminates the need for additional detection coils and position sensors. Identifying the location of the receiver coil in a multi‐transmitter IPT system is achieved through the concurrent optimization of the transmitter coil and its electrical characteristics. The study presents the design of coil grouping and control mechanisms for a 3×3 multi‐transmitter. A mathematical model has been developed for the mutual inductance between receiver and transmitter coils on the X–Y plane. Adaptive cooperative particle swarm optimizer (ACPSO) facilitates the identification of mutual inductance and load parameters in a multi‐transmitter IPT system, positioning the receiver coil in a 2D plane using genetic particle swarm optimization (GAPSO) and a mutual inductance mathematical model. The discrepancy in accuracy between the receiver coil's test coordinates and the absolute coordinates remains below 3.5%. [ABSTRACT FROM AUTHOR]

Chronic wounds affect ~2% of the U.S. population and increase risks of amputation and mortality. Unfortunately, treatments for such wounds are often expensive, complex, and only moderately effective. Electrotherapy represents a cost-effective treatment; however, its reliance on bulky equipment limits its clinical use. Here, we introduce water-powered, electronics-free dressings (WPEDs) that offer a unique solution to this issue. The WPED performs even under harsh conditions--situations wherein many present treatments fail. It uses a flexible, biocompatible magnesium-silver/silver chloride battery and a pair of stimulation electrodes; upon the addition of water, the battery creates a radial electric field. Experiments in diabetic mice confirm the WPED's ability to accelerate wound closure and promote healing by increasing epidermal thickness, modulating inflammation, and promoting angiogenesis. Across preclinical wound models, the WPED-treated group heals faster than the control with wound closure rates comparable to treatments requiring expensive biologics and/or complex electronics. The results demonstrate the WPED's potential as an effective and more practical wound treatment dressing. [ABSTRACT FROM AUTHOR]

Power losses in semiconductor devices present a significant impediment to advancing power electronics systems for achieving higher frequencies, improved efficiency, and greater integration. A major challenge lies in directly coupling power losses with various control strategies, considering the variations in manufacturers, packaging, and process structures within the power electronics field. This paper introduces a field‐circuit coupling simulation methodology of the insulated gate bipolar transistor (IGBT) within the Simulink/COMSOL environment, using a conventional three‐phase six‐switch voltage source inverter (VSI) IGBT module as a case study. A composite transfer function interconnects the electrical and thermal aspects, enabling bidirectional coupling between IGBT temperature and losses. This study aims to comprehensively compare the effects of various control strategies, namely, single‐vector, dual‐vector, and three‐vector current model predictive control (CMPC) and space vector pulse width modulation (SVPWM), on the losses and temperature of IGBT power modules. The findings emphasize that losses are significantly influenced by the selection of weighting factor coefficients and power factor settings under the same CMPC control strategy with a fixed switching frequency. Additionally, the selection of control strategies, such as CMPC and SVPWM, substantially impacts power losses in power electronic devices. [ABSTRACT FROM AUTHOR]

Of late, there has been a tremendous surge in the development of field-effect transistors of various kinds because of their versatile nature of applications in the frontier fields of science and technology. Among them, metal oxide semiconducting field-effect transistors (MOSFET) offer cutting-edge technology in a cost-efficient way of fabricating the device, which focuses on enlarged active area and high area efficiency that could be achieved using simple fabrication processes. The top contact-bottom gate approach has been chosen for the fabrication of an Indium Zinc Oxide MOSFET utilizing silver (Ag) as the source and drain materials. High k-dielectric layer Al2O3 has been deposited onto the n-type phosphorus-doped silicon substrate, which functions as a gate layer. The fabrication process is entailed with the solution processing technique along with the spin coating process. Electrical characterization on the IZO MOSFET shows promising results in the field-effect mobility of 21.37 cm2 V−1 S−1, a subthreshold slope of 0.181 V/decade, and a threshold voltage of 1.2608 V, respectively. The electrical characterization was considered under different atmospheres like dark and daylight showcasing the photoresponsivity which leads to the possible potential for optoelectronic devices. Transport properties of the fabricated IZO MOSFET have been determined by Hall measurements which indicate an electron density of 0.343 × 1023 cm−3 as well as an electron mobility of 2.305 × 10−4 cm2 eV−1 S−1. The structural analyses have been investigated using X-ray diffraction and X-ray photoelectron spectroscopic techniques which could confirm the composition and the film quality of the fabricated materials on the substrate. Surface morphology and structural characterization of the thin film have been studied using SEM and AFM studies. Major applications of IZO MOSFET include power electronics such as power supplies, inverters, and motor control systems. [ABSTRACT FROM AUTHOR]

This article presents a novel approach to enhance the efficiency, control, and power management capabilities of traditional Zeta Converters in renewable energy applications. The proposed particle swarm optimization (PSO)-modified three-port zeta converter (MTPZC) features a multiport structure with dedicated input ports for photovoltaic (PV) and battery sources, along with an output port. The integration of PSO optimization aims to optimize maximum power point tracking to enhance energy extraction. Extensive simulations and experimental validations showcase the MTPZC's superior performance in power extraction from both PV and Battery sources. This innovative design positions the converter as a promising solution for multiport energy conversion systems in renewable energy applications. The article contributes to the advancement of power electronics by offering improved reliability and efficiency. Simulation results, validated in MATLAB and compared with existing methods, demonstrate an impressive efficiency of 97.8%. The MTPZC outperforms existing approaches, indicating lower converter losses and highlighting its potential for practical implementation in diverse renewable energy systems. [ABSTRACT FROM AUTHOR]

Researchers at Kobe University in Japan, in collaboration with National Chung Hsing University in Taiwan, have developed a new electrical power converter design that offers improved efficiency at a lower cost and maintenance. The converter utilizes high-frequency switching and "soft switching" techniques to reduce electromagnetic noise and power losses. The researchers aim to expand the power capacity of the converter in the future. This development has significant applications in various industries, including electric power, renewable energy, transportation, information and telecommunications, and healthcare. [Extracted from the article]

In the fixed time-step electromagnetic transient (EMT)-type program, an interpolation process is applied to deal with switching events. The interpolation method frequently reduces the algorithm's accuracy when dealing with power electronics. In this study, we use the Butcher tableau to analyze the defects of linear interpolation. Then, based on the theories of Runge–Kutta integration, we propose two three-stage diagonally implicit Runge–Kutta (3S-DIRK) algorithms combined with the trapezoidal rule (TR) and backward Euler (BE), respectively, with TR-3S-DIRK and BE2-3S-DIRK for the interpolation and synchronization processes. The proposed numerical integral interpolation scheme has second-order accuracy and does not produce spurious oscillations due to the size change in the time step. The proposed method is compared with the critical damping adjustment method (CDA) and the trapezoidal method, showing that it does not produce spurious numerical oscillations or first-order errors. [ABSTRACT FROM AUTHOR]

Model predictive control (MPC) performance depends on the accuracy of the system model. Moreover, the optimization algorithm of MPC requires numerous online computations. These inherent limitations of MPC hinder its application in power electronics systems. This paper proposes a two-part solution for these challenges for a three-phase inverter with an output LC filter. The first part of the control scheme is a linear and modified model-free approach based on the auto-regressive structure (ARX) with exogenous input. The second part is the computationally efficient optimization algorithm based on the active set method to solve the optimization problem of the MFPC. The objective of the control scheme is to regulate the output voltages of the inverter in the presence of constraints. The constraints are the maximum admissible filter current and optimal duty cycle to avoid any damage to the system. To validate the performance of the proposed control scheme, simulations and hardware-in-loop (HIL) real-time investigations have been performed, comparing the results of the proposed approach with the model-based predictive control. The results showcase the computational efficiency and effectiveness of the MFPC approach, demonstrating its potential for overcoming the limitations of traditional MPC in power electronics systems. [ABSTRACT FROM AUTHOR]

Amorphous IGZO (a‐IGZO) thin‐film transistors (TFTs) are standard backplane electronics to power active‐matrix organic light‐emitting diode (AMOLED) televisions due to their high carrier mobility and negligible low leakage characteristics. Despite their advantages, limitations in color depth arise from a steep subthreshold swing (SS) (≤ 0.1 V/decade), necessitating costly external compensation for IGZO transistors. For mid‐size mobile applications such as OLED tablets and notebooks, it is important to ensure controllable SS value (≥ 0.3 V/decade). In this study, a conversion mechanism during plasma‐enhanced atomic layer deposition (PEALD) is proposed as a feasible route to control the SS. When a pulse of a diethylzinc (DEZn) precursor is exposed to the M2O3 (M = In or Ga) surface layer, partial conversion of the underlying M2O3 to ZnO is predicted on the basis of density function theory calculations. Notably, significant distinctions between In‐Ga‐Zn (Case I) and In‐Zn‐Ga (Case II) films are observed: Case II exhibits a lower growth rate and larger Ga/In ratio. Case II TFTs with a‐IGZO (subcycle ratio of In:Ga:Zn = 3:1:1) show reasonable SS values (313 mV decade−1) and high mobility (µFE) of 29.3 cm2 Vs−1 (Case I: 84 mV decade−1 and 33.4 cm2 Vs−1). The rationale for Case II's reasonable SS values is discussed, attributing it to the plausible formation of In‐Zn defects, supported by technology computer‐aided design (TCAD) simulations. [ABSTRACT FROM AUTHOR]

Generation of green energy is critical for addressing the environmental pollution and saving aquatic life in future by reducing the greenhouse gas. Green energy is generated using sources like wind, water, sun, living plants, and so on. These sources are essential for long‐term efforts to mitigate climate change. The large‐scale use of green energies will contribute to sustainable development which ensure access to reliable, and chemical free energy to power up the portable devices. This research article proposes design of green rechargeable and regenerative battery for brighter future. The proposed battery is not only rechargeable and eco‐friendly but also non‐flammable and can survive at extreme weather conditions T = 70°C (V = 1.52 V, I = 75.5 μA) and T = −65°C (V = 1.52 V, I = 55.2 μA). The electric current of the designed battery also depends on shaking/rotation. The proposed battery can charge 80% to 90% of its initial value within 30 to 40 minutes which makes it a favorable candidate where faster recharging is needed. The designed battery does not show any heating effect even at T = 70°C. Since, battery is free from any chemical, it is therefore does not release any hazardous chemicals once dispose of. [ABSTRACT FROM AUTHOR]

The integration of wind turbines and wind farms into the power grid presents significant challenges, including the variable and uncertain nature of wind power, the need for efficient transmission and distribution of power, and the need for advanced control and monitoring systems. Recent advances in wind turbine and wind farm technology have greatly improved their ability to integrate into the power grid. This includes the use of variable speed generators and power electronics, such as inverters, which allow for more accurate control of the power output and better alignment with the grid's frequency. Additionally, advanced control algorithms, such as model predictive control and feedback linearization, have been developed to improve the stability and reliability of wind power systems. Communication systems have also been integrated into wind power systems to allow for real-time monitoring and control of the wind farm's performance. This improves the ability of the wind farm to provide ancillary services, such as frequency regulation and voltage control. In this work, the major interconnection requirements for the U.S. grid for the expected mass integration of wind farms were discussed focusing on sustainable and reliable control strategies. The paper explores various control schemes that are used for providing response for grid reliability and sustainability. The analysis also included the future steps that OEMs of wind turbines need to take and the regulatory framework that is needed for ancillary services to provide an equitable platform for all generating units – conventional and renewables. [ABSTRACT FROM AUTHOR]

Environmental issues and the global need to increase economically sustainable access to electricity addressed and boosted scientific research and use of Distributed Energy Resources, such as solar Photovoltaic (PV). Multi‐port power converters can be of great interest for a compact and efficient interface between PV, storage units, and DC loads. The Triple Active Bridge (TAB) shows interesting advantages in terms of isolation and Zero Voltage Switching capabilities over wide load and input voltage ranges. This work aims to develop a TAB prototype for a NanoGrid (NG) application, analyzing the possibility of a direct interface of PV modules, storage units, and DC loads, without the use of intermediate conversion stages. The TAB prototype uses Gallium Nitride devices, and an evaluation of the overall efficiency is provided, useful to compare with other isolated three‐port converters. Through an analytical approach, a TAB has been sized and optimized to meet specific application requirements. MATLAB/Simulink simulations have been done for the sizing validation and the control strategy design. A prototype has been developed and experimental measurements have been compared with simulation results. The TAB is proposed as a key element of DC NGs, but applications of interest are also automotive, More Electric Aircraft, and naval applications. [ABSTRACT FROM AUTHOR]

Due to high computation complexity, traditional design methods for LLC converter usually consider limited kinds of performance, and the process for searching the optimal parameter scheme is discrete, which might cause the missing of real optimal solution. In order to solve these problems, a multi‐objectives optimization design method for the LLC converter is proposed in this paper. According to the numerical calculation method, a closed parameter space for resonant parameters is established under the constraints of operation mode, switching frequency, zero voltage switching (ZVS), and voltage stress of resonant capacitor. Besides, the root‐mean‐square (RMS) value of resonant current and secondary current, as well as the core loss of the transformer, are selected as the optimization objectives. Non‐dominated sorting genetic algorithm (NSGA‐II) is utilized to deal with these multi‐objective formulations. In order to reduce the computation complexity, a data‐driven method, called adaptive polynomial approximation (APA), is selected to obtain the explicit expressions of the parameter space and the optimization objectives. Then, by substituting this simplified surrogate model into the NSGA‐II algorithm, the optimal parameter scheme is obtained. The comprehensive comparison analysis is performed, and a 400 W/48 V experimental prototype was built to verify the theoretical analysis, which shows that the proposed method features the highest efficiency of 95%. [ABSTRACT FROM AUTHOR]

Anti‐icing of superhydrophobic materials has attracted a lot of attention. The potential for applications in power electronics, transportation, engineering and other fields is enormous. However, in practical applications, the anti‐icing performance parameters of superhydrophobic materials are still far from meeting the engineering requirements. It is a feasible solution to modify superhydrophobic materials to assist surface deicing by combining the vibration and heat generated by equipment in actual engineering. In this study, conventional superhydrophobic materials are modified by h‐BN. The electrical properties are improved to meet the engineering requirements. At the same time, it reduces the ice adhesion at the interface and improves the thermal conductivity of the material. The modified material has the possibility of assisting in de‐icing in engineering applications. A feasible solution is found for the engineering interface ice‐covering problem. [ABSTRACT FROM AUTHOR]

The paper presents a normalized, varying step size-based least mean square-based control for a standalone microgrid and Ant Lion optimization-based maximum power point tracking. This modified version of the incremental conductance algorithm addresses issues like slow dynamic response, fixed step size issues, and steady state oscillations. Comparative analysis with well-known techniques shows that Ant Lion optimizes the tracking of maximum power points more accurately, with fewer oscillations and increased efficiency. Power management and power quality are maintained through proposed adaptive voltage source converter control. The proposed voltage control shows better performance under various dynamic and steady conditions. [ABSTRACT FROM AUTHOR]

We have developed and simulated a high electron mobility transistor (HEMT) operating in the 5 nm regime. This HEMT uses hafnium oxide (HfO2), a high-k dielectric material, to create an undoped region (UR) beneath the gate. While the gate and undoped regions share equal thickness, the channel length differs. This innovative undoped under the gate dielectric HEMT design mitigates the maximum electric field (V) within the channel area, leading to a significant increase in drain current. The utilization of a high-k dielectric in the HEMT structure results in a saturated Ion current that is 60% higher compared to conventional structures. Specifically, we use an AlGaN/GaN/SiC-based HEMT with an intrinsic section below the gate, using HfO2 as the high-k dielectric substantial, for applications requiring high power and high-frequency power amplifiers. Compare this advanced HEMT design to conventional HEMTs and you will see improved conductivity, a greater drain current (Id), a 54% increase in transconductance (Gm), and a lower on-resistance (Ron). Additionally, advancements in the electric field in the Y direction are seen. This HEMT structure exhibits superior performance compared to alternative materials analyzed. The integration of AlGaN/GaN materials in HEMTs opens up extensive opportunities in the realms of radio frequency very large-scale integration (VLSI) and power electronics. [ABSTRACT FROM AUTHOR]

The existing battery management systems perform many functions, such as simply monitoring the battery's voltage, current, and temperature for the most basic and compensating energy imbalances between battery cells for the most advanced systems. In this last example, the function balancing helps protect the battery from obtaining a better lifespan. However, these systems with such functions remain complex because they involve techniques specific to power electronics and energy conversion. The number of components, implementation complexity, and cost increased. The work presented in this paper fits directly into this context. The main objective is to provide a solution to the problem of battery management and careful pack cell balancing. The proposed system aims to balance the battery pack cells based on the intermediate state of charge by charging or discharging the imbalanced cell. The implementation of the proposed control strategy was for a battery pack composed of five cells under MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

Power conversion systems for wireless power transfer (WPT) applications have demanding requirements for continuity of service, besides being operated with stressing environmental conditions. Diagnostic and prognostic programs are thus quite useful and this work shows a novel approach based on the analysis of spectra of an autoregressive (AR) model to recognize a wide range of faulty devices, including incipient faults, when deviations from nominal parameters begin to manifest. AR modeling provides cleaner and easier to interpret spectra, where only the salient features remain, and they are more sensitive to variations in the corresponding time domain waveforms. A log spectral distance is calculated that successfully separates healthy and faulty states of the feeding single-phase inverter, even in challenging scenarios of poor signal-to-noise ratio. [ABSTRACT FROM AUTHOR]

The application of GaN HEMTs on silicon substrates in high-voltage environments is significantly limited due to their complex buffer layer structure and the difficulty in controlling wafer warpage. In this work, we successfully fabricated GaN power HEMTs on 6-inch sapphire substrates using a CMOS-compatible process. A 1.5 µm thin GaN buffer layer with excellent uniformity and a 20 nm in situ SiN gate dielectric ensured uniformly distributed VTH and RON across the entire 6-inch wafer. The fabricated devices with an LGD of 30 µm and WG of 36 mm exhibited an RON of 18.06 Ω·mm and an off-state breakdown voltage of over 3 kV. The electrical mapping visualizes the high uniformity of RON and VTH distributed across the whole 6-inch wafer, which is of great significance in promoting the applications of GaN power HEMTs for medium-voltage power electronics in the future. [ABSTRACT FROM AUTHOR]

Featured Application: Given the increased use of high-voltage DC (HVDC) systems and the conversion of AC to DC using power electronics with faster switching times, the issue of electromagnetic interference (EMI) is receiving more attention. In this paper, the origin and evolution of EMI to the outside of HVDC converter stations is examined along with measures for managing this EMI. The electromagnetic interference (EMI) generated by switching operations within high-voltage DC (HVDC) converter stations is an issue that has been addressed by CIGRE, and methods to manage EMI should be considered in the design phase using electromagnetic modeling techniques. It is shown that the methods of the moments-based techniques that have been used in many previous studies may not be sufficient. Here, a finite-difference time-domain method is used to study the properties of single switching events using a realistic model of an HVDC converter station with a special emphasis on determining the impact of the valve hall on shielding EMI. It is shown that the valve hall does not confine high-frequency electromagnetic fields to the valve hall; rather, it delays them from exiting through bushings in the wall and spreads them out in time. Further, it is shown that incorporating electromagnetic absorbing material into the valve hall's design can significantly reduce EMI outside the converter station. [ABSTRACT FROM AUTHOR]

Ferrite magnetic materials are excellent materials for the fabrication of ferrite core inductors. Here, rare-earth La3+ -doped cobalt ferrites, CoFe2-xLaxO4 (x = 0.0, 0.10, and 0.20) have been produced using the eco-friendly sol–gel auto-combustion method. The laboratory-made samples were utilized for the fabrication of ferrite core/rod inductors. The obtained nanomaterials were tested for structural and microstructural characterizations using x-ray diffraction (XRD), infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) techniques. The XRD outcomes confirmed the single phase (Fd-3 m space group) nanocrystalline nature with sizes ranging ~ 36 nm to 40 nm for all the product samples, which was also verified by the TEM analysis (38–40 nm). FTIR spectra showed characteristic bands for metal–oxygen (M-O) stretching vibrations from the tetrahedral site near 463–467 cm−1 and from the octahedral site at 689–696 cm−1 for all the fabricated samples. On La3+ doping in the CoFe2O4 matrix, a minor change in band positions was caused due to the microstructure. The ferrite rod inductors had an inductance (L) that ranged from ~ 140 µH to 200 µH. With the addition of La3+, the electro-magnetic characteristics of the cobalt ferrite nanocrystals underwent a transformation, which led to an increase in inductance of the ferrite rod inductors. The ferrite core inductors that have been acquired can be advantageous for electrical circuits in power electronics, microwaves, and cellular technology applications. [ABSTRACT FROM AUTHOR]

This comprehensive review delves into the intricate realm of GaN-based metal–oxide–semiconductor (MOS) high-electron-mobility transistors (HEMTs), providing an exhaustive analysis of their contemporary DC and radio-frequency (RF) performance. Despite familiar challenges in the instability of threshold voltage (VTH) observed in GaN MOSHEMTs, recent innovations in interface technologies, incorporating in situ SiNx and surface oxidation of (Al)GaN, have led to exceptional DC and dynamic performances, achieving stability in VTH by reducing surface states, minimizing interface traps, controlling surface potential, and enhancing interface quality. Adoption of high-κ dielectric materials is emphasized since they are indispensable, as they play a crucial role in improving the electrostatic control of the gate and reducing parasitic capacitance, and contribute to achieving low gate leakage, high gm, small VTH fluctuation, and small current collapse. The recent aspects of the AlGaN/GaN MOSHEMT devices are presented, and the impacts of structural breakthroughs are discussed. When compared to single-layer arrangements, the utilization of multilayer gate stacks can provide improved gate control and less leakage. Tailoring the electric field distribution and enhancing device performance for particular applications or operational conditions are made possible by engineering the gate stack arrangement. This review also discusses fabrication challenges and reliability issues in GaN-based MOSHEMTs, highlighting innovative manufacturing techniques and shedding light on ongoing research to address these challenges. By presenting a comprehensive overview of recent developments and emerging trends, this review aims to contribute valuable insights for researchers and practitioners in the dynamic and expanding field of GaN-based RF power electronics and sensing technologies. [ABSTRACT FROM AUTHOR]

This paper introduces a new direct step‐up ac‐ac converter designed based on the SEPIC. It provides a higher step‐up conversion ratio than other counterparts with valuable features like high efficiency, reasonable input and output total harmonic distortions (THD), continuous input current waveform, common ground, few components, and single‐stage conversion without snubber and LC filters. Unlike most counterparts, the duty cycle can be varied between zero and one in boost operation and is not limited to any value below one. The voltage stress on one switch is reduced by increasing the winding coefficient of the utilized coupled inductor, and current stress on another is independent of this coefficient. It reduces the switches' losses and improves the converter efficiency. Thanks to the above attributes, the proposed converter is suitable for inductive power transfer from low‐voltage ac sources, operating as an ac voltage regulator for sensitive ac loads, and any applications that require a boost converter with few components. This article shows the converter's operation principle and evaluates its performance through experiments on a 225 W prototype. Accordingly, the maximum obtained efficiency is 95.4%. The input and output current THDs for the nominal inductive load equal 4.5 and 2.8%, respectively. Results confirm the claims. [ABSTRACT FROM AUTHOR]

This paper investigates the stability and reliability analysis of a non‐isolated high‐gain DC‐DC converter. The proposed DC‐DC converter produces a high gain output voltage with a lower duty ratio and reduced voltage stress on the semiconductor switch. A reliability analysis is performed to predict the failure rate and lifetime of the individual components using the military handbook (MIL‐HDBK‐217F). A state space equation and small signal modeling of the proposed converter are derived to elucidate the performance of the proposed converter through stability analysis. A closed‐loop using PID controller is incorporated to attain the constant regulated output voltage during sudden parameter changes. The validation of the closed‐loop using the PID controller is verified with the wide range of variations in the different parameters, such as input voltage, load value, and reference voltage value. The laboratory‐based prototype is developed for the proposed converter and validated the performance with 250 W. The power density and efficiency of the proposed converter are 1.360 kW/L and 93%, respectively. [ABSTRACT FROM AUTHOR]

Most high‐gain step‐up dc‐dc structures operate with a limited duty cycle and suffer from a high component count, limiting their application. This paper addresses these problems by proposing a new step‐up dc‐dc converter that provides a high conversion ratio with few elements. Two coupled inductors are used instead of conventional voltage multiplier cells to improve the gain without excessive components. The topology includes one switch whose duty cycle is not limited and can vary between zero and one according to the output voltage condition. It has been placed on the low‐voltage side of the converter that encounters low‐voltage stress. It is selected from low‐voltage rating switches with small on‐resistance, which reduces the conduction loss of the switch and improves the efficiency. High boost factor, high efficiency, reasonable component counts, improved gain‐to‐element ratio, and low voltage stress on the switch distinguishe the converter from their counterparts. The topology also benefits from the common‐ground feature. However, its input current waveform is pulsating. This article describes the theory and operation principle of the topology in detail. Experimental results are represented to evaluate the converter's performance and operation. In this case, a 240 W prototype has been designed and fabricated. Results confirm the above claims. [ABSTRACT FROM AUTHOR]

Most coupled inductor‐based step‐up DC–DC converters encounter a significant voltage overshoot on their power switch due to the leakage inductance of the coupled inductor. So, they need additional bulky snubber circuits or a sophisticated procedure for coupled inductor design to reduce that effect. This paper proposes an improved coupled inductor‐based DC–DC converter, which provides a high quadratic voltage conversion ratio without excessive voltage stresses on the power switch. An active clamp circuit that operates with the zero‐voltage switching (ZVS) feature has been utilized for this aim. This feature allows the main power switch to be selected from low voltage ratings and low on‐resistance MOSFETs, which reduces conduction loss. The topology also benefits from continuous input current, high gain, high efficiency, and an appropriate number of components compared with the produced gain. In this article, the theory and operation of this converter are described by proposing the dc and small‐signal models, loss model, and continuous and discontinuous current modes (CCM and DCM) relations. Experimental results are represented to evaluate the performance of the proposed topology. For this purpose, a 240 V/240 W prototype has been designed and fabricated. Results confirm the above claims. [ABSTRACT FROM AUTHOR]

This paper proposes an isolated single‐phase impedance‐source ac‐ac converter with a wide voltage conversion ratio and a safe commutation strategy. The new topology has noteworthy features like continuous input current, galvanic isolation, and non‐inverting and inverting buck‐boost modes with a wide voltage coverage. Also, only one switch operates with high‐frequency PWM signals, reducing the semiconductor switching loss. The galvanic isolation has been achieved by employing a high‐frequency transformer (HFT), eliminating low‐frequency transformers (LFT) from the topology. A safe commutation strategy has been designed and applied to the converter to mitigate the voltage and current spikes on power switches, which eliminates additional snubber circuits. A prototype has been designed to validate the suggested converter performance in stand‐alone and DVR applications. The peak obtained efficiency equals 96.1% and 94.9% in inverting and non‐inverting step‐down and step‐up modes, respectively, validated by an accurate power loss model and experimental results. Experimental results confirm the theory and operation of the proposed converter. [ABSTRACT FROM AUTHOR]

The provision of wireless and battery-free power is key to extending the applications of body-worn sensing electronics. This paper investigates the design of an IPT system for a body-worn scenario where the challenges include highly variable coupling, the requirement for the coil/s to be flexible, and close proximity to the body. Variable coupling results in a system that must operate with received powers ranging over orders of magnitude, whilst the use of flexible coils reduces the Q-factor and results in the potential for inductance variation. The human exposure considerations limit both the maximum field strengths that the wearer of a receiver coil might experience and the field strengths that a third party might be exposed to. In this paper, analytical models are used to identify key design variables and to guide the design synthesis of an IPT system for a wrist-worn medical sensor. Practical circuits to drive the transmit coil and to interface the receive coil with the load electronics are described. A prototype system is tested to validate the theoretical analysis, providing power greater than 2 mW to the sensor over a hemispherical region up to 250 mm in radius from the transmit coil. [ABSTRACT FROM AUTHOR]

Electrostatic capacitors, with the advantages of high-power density, fast charging–discharging, and outstanding cyclic stability, have become important energy storage devices for modern power electronics. However, the insulation performance of the dielectrics in capacitors will significantly deteriorate under the conditions of high temperatures and electric fields, resulting in limited capacitive performance. In this paper, we report a method to improve the high-temperature energy storage performance of a polymer dielectric for capacitors by incorporating an extremely low loading of 0.5 wt% carbon quantum dots (CQDs) into a fluorene polyester (FPE) polymer. CQDs possess a high electron affinity energy, enabling them to capture migrating carriers and exhibit a unique Coulomb-blocking effect to scatter electrons, thereby restricting electron migration. As a result, the breakdown strength and energy storage properties of the CQD/FPE nanocomposites are significantly enhanced. For instance, the energy density of 0.5 wt% CQD/FPE nanocomposites at room temperature, with an efficiency (η) exceeding 90%, reached 9.6 J/cm3. At the discharge energy density of 0.5 wt%, the CQD/FPE nanocomposites remained at 4.53 J/cm3 with an efficiency (η) exceeding 90% at 150 °C, which surpasses lots of reported results. [ABSTRACT FROM AUTHOR]

NaNbO3(NN)-based lead-free materials are attracting widespread attention due to their environment-friendly and complex phase transitions, which can satisfy the miniaturization and integration for future electronic components. However, NN materials usually have large remanent polarization and obvious hysteresis, which are not conducive to energy storage. In this work, we investigated the effect of introducing CaTiO3((1−x)NaNbO3-xCaTiO3) on the physical properties of NN. The results indicated that as x increased, the surface topography, oxygen vacancy and dielectric loss of the thin films were significantly improved when optimal value was achieved at x = 0.1. Moreover, the 0.9NN-0.1CT thin film shows reversible polarization domain structures and well-established piezoresponse hysteresis loops. These results indicate that our thin films have potential application in future advanced pulsed power electronics. [ABSTRACT FROM AUTHOR]

The paper is devoted to analysis of power losses in a resistance welding machine including supplying system and examination of welding conditions of the welding machine current in a case of synchronous (simultaneous) operation of multiple welding machines, i.e., during the conduction of welding current. Analysis of the most important contributors of power losses generated on the current path between a power source and the welded joint is carried out. The analysis is carried out for a DC (direct current) welding machine with power electronics inverter. AC (alternating current) welding machines are also taken into account. The analysis is divided in two parts. The first one is the analysis of single welding machine operation, while in the second part, coexistence (mutual operation) of two synchronous welding machines is considered. The analysis is based on results of numerical and experimental investigations. The first one is focused on calculation of power losses in the energy path (including a Sankey type power loss distribution diagrams), and the second one is based on experimental tests carried out to determine the diameter of the weld nugget and the strength of the joints, for cases of reducing the welding current. An example of simultaneous operation of welding machines was presented and discussed. The percentage voltage drops and power losses in the entire power supply path of the resistance welder are shown. The analysis carried out is extremely important from this point quality of welded joints. [ABSTRACT FROM AUTHOR]