Efficient Electronic Systems Research Articles

A numerical simulation of heat transfer performance on MHD nanofluids in porous metal for enhancing CPU cooling efficiency

The main goal of this study is to enhance CPU cooling efficiency using nanofluids, and the novelty of the study lies in the investigation of heat transfer and convective flow of MHD nanofluid through porous metal structures and foam heat sink/source to improve CPU cooling efficiency. The governing equations for the flow model are solved using the BVP4C with MATLAB package through shooting techniques. The effects of various parameters on velocity, temperature fields, HT and drag force are discussed through graphical simulations. The results indicate that as the Reynolds and Darcy numbers rise, fluid flow velocity undergoes unique alterations. Higher Reynolds and Darcy numbers result in cooler temperatures, while higher heat generation lead to warmer temperatures.Boosting Prandtl number improves HT by 52% with Cu nanoparticles, whereas elevating heat generation values reduce HT by 6.43% more efficiently with Cu nanoparticles than Al2O3 nanoparticles. Raising the Hartmann number would boost drag force, but the Darcy number opposes it. An increase in Hartmann number leads to a decrease in HT by 30.16% for Al2O3-H2O nanofluids and 47.81% for Cu-H2O nanofluids. The findings contribute to the development of advanced computing devices, paving the way for more efficient and reliable electronic systems in various applications.

Assessment and improvement of adhesion of printed silver-based inks on alumina produced by fused filament fabrication

More efficient electronic systems need more temperature-stable substrate materials and more flexible production possibilities. Ceramics such as alumina can be used for 2D and 3D base bodies, since they provide better thermal properties than their polymeric counterparts and can be additively manufactured utilizing e.g. Fused Filament Fabrication. Proper functionalization can be achieved by applying methods of printed electronics. Here, adhesion of the functional ink to a substrate is a crucial issue and especially challenging on ceramic substrates. This contribution reached a noteworthy increase in this matter, using a modified silver-based ink with piezojet-printing, while preserving very low electrical resistance after convection sintering. Adhesion is determined by pull-off testing, based on ISO 4624. By the approach shown in this work, printed ceramics could become a more viable choice for use in functional electronic systems.

Evaluation of Different Methodologies for Wave Energy Conversion Systems Integration into the Power Grid Using Power Hardware-in-Loop Emulation

The ocean energy resources hold the promise of a sustainable solution within global efforts to diversify energy sources and mitigate climate change. Wave energy conversion (WEC) systems, as emerging technologies, offer adaptability and the potential to harness predictable wave energy. However, integration of WEC systems into a power grid brings challenges for system operators due to their nature of operation. Addressing these demands is a multilayered process that involves highly efficient power electronic devices, control systems, and efficient energy storage solutions. This paper specifically focuses on the methodologies of the grid integration of a specific wave energy conversion system—a point absorber developed by the company Sigma Energy. Proposed methodologies are experimentally tested using power hardware-in-loop (PHIL) emulation of a fully monitored and controlled small-scale microgrid equipped with a battery energy storage system (BESS), different emulators of loads, and distributed generators (DG).

Comparative Analysis of 5-Level and 7-Level Single-Phase Cascaded H-bridge Multilevel Inverters

The demand for high-performance, efficient, and reliable power electronic systems has been steadily increasing in various industrial applications, including renewable energy systems, electric vehicles, and smart grids. In response to this demand, the Cascaded H-Bridge Multi-level Inverter (CHB-MLI) has emerged as a promising solution, offering advantages such as improved voltage waveform quality, reduced harmonic distortion, and enhanced power handling capabilities. The CHB-MLI is characterized by its modular structure, comprising multiple H-bridge cells cascaded in series. Each H-bridge cell operates with a separate DC power source, enabling the generation of stepped voltage levels at the inverter output. By intelligently controlling the individual H-bridge cells, the CHB-MLI achieves the synthesis of a high-quality multilevel output voltage waveform. The different multi-level inverter topologies are Diode-Clamped MLI, Capacitor-Clamped MLI and Cascaded H-bridge MLI. This paper focused on key aspects like design, simulation, control strategies, performance evaluation, overall comparison and analysis of 5-level and 7-level CHB-MLIs. By addressing these aspects, this paper aimed to contribute to the advancement of power electronics technology and promote the adoption of the CHB-MLI in real-world applications, fostering energy efficiency and sustainability in power conversion systems. Index Terms: Inverter, Multi-level inverter, CHBMLI, switching, SPWM, MCSPWM, gate signal, waveform, harmonics, THD, MATLAB.

WAYS TO REDUCE THE IMPACT OF PULSATIONS IN LOCAL POWER SUPPLY ROBOTIC SYSTEMS

An analysis of the changes in the flow of pulsation transforming the energy-dynamic indicators of on-board power electronics systems has shown that there are several options for solving this problem.
 The article outlines the main options for the current problem of pulsation in the energy systems of autonomous electrical systems, such as UAVs, robotic complexes, and other systems. The effectiveness of changes in pulsation is examined, in addition to directly assessing the effectiveness of stagnation strategies and methods. Also in the statistics, the optimal technical solutions for specific operating minds were identified.
 The prospects and future directives have been predicted based on the proposals for further research in the sphere of changes in pulsation in local life systems.
 In the future, it is predicted and supported by the development of technology and innovation in this country.
 To sum up, we can say that the statistics have analyzed the changes in pulsation in robotic local power supply systems, which is one of the key directions in the field of electrical engineering and electronics. Increased attention to this problem is due to the need for assured stability, reliability and greater energy efficiency of electronic systems. Research in this area is aimed at developing more comprehensive methods and strategies for reducing noise and pulsation in electrical systems.
 Assessing the effectiveness of stagnant methods, promoting the development of new technologies and innovation, as well as developing promising directions in this field opens the way to creating more stable and adaptive living systems. Replacement of advanced electronic filters, voltage stabilizers, selection of new materials and components, integration of intelligent energy management systems and optimization of essential energy resources local power supply systems – the whole purpose is to directly conduct further investigations.
 The growing demand for stable and efficient electronic systems is driven by current research and the introduction of new technologies to change pulsation. Technological developments and scientific research in this area open up broad prospects for reducing the power supply and ensuring the stability of the functioning of modern electronic devices.

A Systematic Literature Review of Current Trends in Electronic Voting System Protection Using Modern Cryptography

Electronic voting, based on cryptographic protocols and blockchain technology, represents an advanced method for ensuring the security, transparency, and reliability of electoral processes. The scientific research presented in this article is devoted to the analysis of trends and advanced technologies in the field of electronic voting. The authors propose a systematic mapping of this area using bibliometric analysis. The research is based on the analysis of scientific articles extracted from the Web of Science and Scopus databases. Bibliometric analysis tools are used to automatically identify key topics and trends in the literature. The results of the study reveal the key directions of the development of electronic voting, including the integration of cryptographic protocols and blockchain technology. Specific aspects include improving privacy through the use of modern cryptographic protocols, creating an immutable register of votes using blockchain technology, ensuring trust through open-source code, and increasing resilience to cyber-attacks. These areas reflect the desire to develop efficient, transparent, and secure electronic voting systems. Based on the identified trends, recommendations are proposed for further research aimed at improving electronic electoral systems and their adaptation to the modern requirements of security and transparency in electoral processes.

The advantages and short circuit characteristics of SiC MOSFETs

SiC MOSFETs have exhibited considerable benefits in high-frequency, high-voltage, and high-temperature power electronics applications with outstanding material attributes as a result of the rapid advancement of power electronics technology. SiC MOSFETs slower short-circuit tolerance and faster switching rates provide new issues for the short-circuit prevention technology. In the opening section of the study, Si and SiC MOSFETs are compared and evaluated using various models and parametric factors. It has been demonstrated that SiC MOSFETs outperform Si MOSFETs in a variety of conditions and applications. The many SiC MOSFET short-circuit failure types as well as their underlying theories are initially explained in the papers main body. In addition, it examines the fundamentals of short-circuit test procedures and SiC MOSFET test circuits. The issues and limitations of the currently available SiC MOSFET short-circuit protection technology are then explored, along with factors impacting the short-circuit of SiC MOSFETs that are thoroughly examined. Lastly, the SiC MOSFET short-circuit protection technology development trend is forecasted, and potential future areas for improvement and innovation are considered. SiC MOSFET short-circuit protection technology will be enhanced and optimized to satisfy the needs of efficient and dependable power electronic systems as technology advances and application requirements expand.

Maximizing Foreign Direct Investment Returns: Unravelling the Complexities and Overcoming Challenges in Dividend Withholding Tax Reclaim Processes

This article explores the complexities surrounding dividend withholding tax reclaim processes and their impact on foreign direct investment returns. It first highlights the growing trend of investors seeking opportunities outside their local stock exchanges and investing in shares abroad or dual-listed shares. Through advanced technology, cross-border transactions have become more prevalent, allowing resident investors to easily purchase shares in foreign markets and non-resident investors to invest in local markets.The refund process often involves submitting extensive documentation, lengthy processing times, potential time limitations for claiming refunds, burdensome administrative procedures, language barriers in foreign jurisdictions, unfamiliar legal requirements, and the possibility of audits or reviews by tax authorities to validate refund claims. Examining these complexities and their impact, this article employs a doctrinal research approach comparing different treaty practices across the Southern African Development Community, also in relation to third countries. It reveals that the complexities of dividend withholding tax reclaim processes significantly affect foreign direct investors’ returns on investment. The article emphasizes the importance of enhancing transparency and consistency in these processes, streamlining documentation requirements, and developing efficient electronic systems.

Catalysing Democracy: Exploring Security and Performance in Blockchain-Based Electronic Voting Systems and Centralized Solutions

Abstract: This research paper conducts a comprehensive comparative study between blockchain-based electronic voting systems and centralized solutions, focusing on their security and performance attributes. Acknowledging the significance of electronic voting in modern democracies, the study delves into blockchain's role in enhancing security and transparency while addressing potential challenges. Through an in-depth literature review, the paper examines the existing research landscape, highlighting security aspects, performance evaluations, and the impact of decentralization. The subsequent analyses dissect the security features, enhancements, vulnerabilities, and potential attacks in each system, followed by a thorough performance assessment encompassing transaction speed, scalability, and resource consumption. The interplay between security and performance tradeoffs is explored, culminating in a discussion of the research's implications, future directions, and ethical considerations. The study's significance lies in guiding decision-making, promoting balance, and fostering ongoing innovation in the pursuit of secure and efficient electronic voting systems.

An Overview of Strengths and Weaknesses in Using MOSFET Experience for Modeling GaN HEMT

GaN high electron mobility transistors (HEMTs) represent an emerging and key enabling technology for obtaining highly efficient and compact power electronic systems. The use of circuit models of power devices is essential for the optimal design of power converters, but while they have been deeply investigated for power MOSFETs and IGBTs, GaN HEMT models are still in their early stages. This paper first discusses the main similarities and differences between conventional MOSFETs and GaN HEMTs in terms of the datasheet information that the device manufacturers use to obtain the behavioral models that they usually provide as Spice-like netlists. Then, it highlights the strengths and weaknesses of using the behavioral models of MOSFET for GaN HEMT. To achieve this aim, a study of the existing GaN HEMT models revealed the lack of a proper modeling strategy for the dynamic conduction resistance, which is the most critical aspect of HEMT modeling. The difficulty is due to the dependence of the dynamic conduction resistance on quantities related to the application, which is a behavior absent in power MOSFETs. Consequently, future research efforts on GaN HEMT modeling must face this issue.

Design of a LED driver with a flyback topology for intelligent lighting systems with high power and efficiency

Considered in this paper are the parameters and characteristics of the developed highly efficient electronic control systems for powerful LED modules (drivers), built on the basis of a single-stage flyback converter with a nominal power close to 200 W. The results of experimental tests show that, at the nominal load, the minimum efficiency of the developed driver reaches 88.2% with the power factor above 0.97 and the coefficient of total harmonic current distortion close to 23.4%. With the maximum value of the efficiency factor of the developed system 90.3% and the supply voltage 240 V, the power factor is higher than 0.99, and the total harmonic current distortion is 3.6%. The values of current harmonics of the driver do not exceed the maximum allowable values defined by the current standards. Used driver construction topology enabled to reduce the cost of the final product due to the unification of the component base, which increases the availability and manufacturability of the design. The use of a modern element base made it possible to ensure the deviation of the output current from the set one by no more than 1% over the whole range of the operating voltage of the supply (180…250 V), which allows using the developed driver in intelligent lighting systems and lighting systems with a combined power supply.

Systematic review of facilitators and barriers to community pharmacists’ role in licit opioid misuse prevention

Abstract Introduction The prescribing rate of Opioids is increasing and is perceived as main contributor to opioid misuse.1,2 Community pharmacists can help reduce opioid misuse rates by carrying out licit opioid misuse prevention services.3 Understanding and reviewing the barriers and facilitators to community pharmacists’ involvement in the prevention of licit (over-the-counter and prescription) opioid misuse prevention services have the potential to significantly improve these services. Aim To identify, collate and synthesise existing evidence of stakeholders’ views regarding barriers and facilitators to community pharmacists’ role in licit opioid misuse. Methods A systematic review of original studies was carried out in MEDLINE, Embase, Scopus, Web of Science, CINAHL, and APA PsycINFO using search terms for community pharmacy, opioid misuse interventions and opioid misuse. Titles, abstract and full text were independently reviewed by two researchers and consensus on eligibility of included studies was reached. Studies were included if they were: either qualitative or mixed methods studies of community pharmacy and licit opioid misuse; published in English; either over-the-counter or prescription opioids. Quantitative, non-English studies; and studies on illicit opioids were excluded. Narrative synthesis was carried out by: developing a theory of change model, data extraction and thematic analysis, discussing relationship and robustness of studies. Quality assessment was carried out by the Joanna Briggs Institute critical appraisal checklist. Ethical approval was obtained from Newcastle University Faculty of Medical Sciences Research ethics committee. Results A total of 1,234 articles were retrieved from all database searches. After deduplication, title, abstract screening and data extraction, 10 studies were included. Barriers and facilitators identified are knowledge and skill, pharmacists’ attitude, relationship with prescribers, time, number of support staff, remuneration of service, scheduling of over-the-counter opioids, corporate pharmacy support, private counseling room and electronic programmes. The factors grouped as: capabilities are knowledge and skill; opportunities include relationship with prescribers, time, number of support staff, remuneration of services, scheduling of over-the-counter opioids, corporate pharmacy support, private counseling room and electronic programmes while motivation was Pharmacists’ attitude. Discussion/Conclusion Overall, Study opines that: (1) improving capabilities and opportunities will improve motivation of the Community Pharmacists; (2) improved motivation of Community Pharmacists will improve their involvement in the prevention of licit opioids misuse. (3) Improved capability could be achieved by implementation of policies that focus on: improving opioid misuse education at the undergraduate level and routine training of community pharmacists; while (4) improved opportunity could be achieved by implementing integrated pharmacy care model (a health system in which community pharmacists and prescribers collaborate), increased number of pharmacy support staff, remuneration for service, upscheduling of OTC opioids, pharmacy managers’ support, modifying the community pharmacy setting to include a private consultation area and efficient electronic systems. Findings of this study may not be generalized to developing countries because majority of the studies included in the review were carried out in developed countries. However, implementation of these factors (by policy makers, pharmacy managers) will improve community pharmacists’ attitude towards the provision of licit opioid misuse prevention services resulting in improved community pharmacists’ involvement in these services.

Triboelectric Nanogenerators in Sustainable Chemical Sensors

The rapid development of sensing technology has created an urgent need for chemical sensor systems that can be rationally integrated into efficient, sustainable, and wearable electronic systems. In this case, the triboelectric nanogenerator (TENG) is expected to be a major impetus to such innovation because it can not only power the sensor by scavenging mechanical energies and transforming them into electricity but also act as the chemical sensor itself due to its intrinsic sensitivity towards the chemical reaction that occurs at the triboelectric interface. In this review, recent research achievements of chemical sensors that are based on TENGs are comprehensively reviewed according to the role of TENGs in the system, that is, pure power supplies or self-powered active chemical sensors. Focus is put on discussing the design criteria and practical applications of the TENG-based active sensors in different fields, which is unfolded with a classification that includes biosensors, gas sensors, and ion sensors. The materials selection, working mechanism, and design strategies of TENG-based active chemical sensor systems (CSSs) are also discussed, ending with a concise illustration of the key challenges and possible corresponding solutions. We hope this review will bring inspiration for the creation and development of TENG-based chemical sensors with higher sensitivity, simpler structure, and enhanced reliability.

Analysis of Non-Minimum Phase System for AC/DC Battery Charger Power Factor Correction Converter

Electric mobility is nowadays one of the more important trends regarding pollution reduction and global warming due to fuel consumption. Big efforts are done in order to develop efficient and reliable power electronic systems for electric vehicles. In two stage on board-battery chargers, one way of improving efficiency is by means of ensuring the DC-DC isolated converter always operates in the nominal input/output voltage ratio, that could be achieved with a variable DC-link operation. In this paper, a four-switch buck-boost based AC/DC converter is deeply analyzed in order to improve its dynamic performance, the power factor and the total harmonic distortion. The converter suffers from a non-minimum phase characteristic in different input–output transfer functions, which reduces the closed-loop bandwidth of the system. Therefore, after a deep converter analysis has been done, different solutions have been evaluated and tested. Finally, a control to different output transfer functions of the converter become minimum phase, which allows us to increase the system bandwidth and, consequently, high power factor, low harmonics distortion, single control structure and fast dynamics for wide output voltage range are achieved.

Measurement and Analysis of Power Losses in Sintered Cores for Power Electronic Devices in Renewable Energy Systems

Abstract Measurement of power losses in inductive devices in highly efficient power electronic systems is crucial for choosing appropriate components. A calorimetric method for measuring power losses below 10 W is presented in the following paper to decompose the inductive devices’ power losses. A fully enclosed double-jacked calorimetric chamber is constructed to measure the temperature with digital temperature sensors TMP275, providing a resolution of 0.1 W/K. The finite element method is used with analytical calculation to estimate core and conduction losses to decompose power losses. Power losses are measured for an inductor with a 3C95 ferrite core and four types of windings, where three were made of wire with a different number of strands, whereas the fourth has been made using copper foil. All windings have similar cross-sectional areas for comparison.

Busbar Current Measurement With Elliptical Sensor Arrays Without Conductor Specific Calibration

In highly efficient power electronic systems, circular arrays of magnetic field sensors offer numerous advantages compared to older magnetic core-based sensors. They feature low power consumption, low weight, and high immunity to external magnetic fields. In power converters, conductors with a rectangular cross section, a small height, and a large width are widely used. Thus, an elliptical sensor array could reduce the space needed for the current sensor, e.g., in a power converter by a factor of four or more compared to a circular sensor array. In this work, we theoretically and experimentally study the sensitivity error caused by the change of the conductor geometry. Therefore, we calibrated different elliptical sensor arrays on a circular conductor and determined the sensitivity error for the use of flat conductors with different widths. This calibration on a circular conductor avoids a costly conductor-specific calibration of the sensor array in the application. Two different distribution methods for elliptical sensor arrays and different ratios of the semiaxes are considered. In addition, the influence of the number of sensors and the starting position for the sensors are examined. The presented elliptical sensor arrays can be used to measure the current carried by a flat conductor largely independent of its width. For some aspect ratios, they even offer a lower sensitivity error than circular sensor arrays. In this article, design considerations for those elliptic sensor arrays are given.

Power Electronics Based on Wide-Bandgap Semiconductors: Opportunities and Challenges

The expansion of the electric vehicle market is driving the request for efficient and reliable power electronic systems for electric energy conversion and processing. The efficiency, size, and cost of a power system is strongly related to the performance of power semiconductor devices, where massive industrial investments and intense research efforts are being devoted to new wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN). The electrical and thermal properties of SiC and GaN enable the fabrication of semiconductor power devices with performance well beyond the limits of silicon. However, a massive migration of the power electronics industry towards WBG materials can be obtained only once the corresponding fabrication technology reaches a sufficient maturity and a competitive cost. In this paper, we present a perspective of power electronics based on WBG semiconductors, from fundamental material characteristics of SiC and GaN to their potential impacts on the power semiconductor device market. Some application cases are also presented, with specific benchmarks against a corresponding implementation realized with silicon devices, focusing on both achievable performance and system cost.

Measurement of Power Dissipation Due to Parasitic Capacitances of Power MOSFETs

Analysis of the switching losses in a power MOSFET is crucial for the design of efficient power electronic systems. Currently, the state-of-the-art technique is based on measured drain current and drain-to-source voltage during the switching intervals. However, this technique does not separate the switching power due to the resistance of the MOSFET channel and due to the parasitic capacitances. In this paper, we propose a measurement method to extract the power dissipation due to the parasitic capacitances of a MOSFET, providing useful information for device selection and for the design of efficient power electronic systems. The proposed method is demonstrated on a basic boost converter. The proposed method shows that the existing method underestimates the turn-On losses by 41% and overestimates the turn-Off losses by 35%.

Reversible Realization of N-bit Arithmetic Circuit for Low Power Loss ALU Applications

Today, low loss efficient digital calculating systems are among the key focus of researchers. Fast and efficient processing parts are in the concrete demands of this era. Reversible digital design approach is directed towards this need of efficient electronic system design. Arithmetic circuits are considered as the main part of any digital calculating system. Designing of these arithmetic subsystems using reversible design approach leads to the generation of low power loss efficient electronic systems. In this paper, we have proposed a novel approach to design n-bit arithmetic circuit with reversible design approach. This proposed design is compared with existing designs on the basis of some selected performance parameters. Comparison and analysis of these designs show that proposed design is the most optimized approach for reversible realization of arithmetic circuit for low power Arithmetic logic unit (ALU) circuit applications. The proposed model can be used for reversible design of digital computing systems for low power ALU designs.

Power Semiconductor Devices for Smart Grid and Renewable Energy Systems

Modern civilization is related to the increased use of electric energy for industry production, human mobility, and comfortable living. Highly efficient and reliable power electronic systems, which convert and process electric energy from one form to the other, are critical for smart grid and renewable energy systems. The power semiconductor device, as the cornerstone technology in a power electronics system, plays a pivotal role in determining the system efficiency, size, and cost. Starting from the invention and commercialization of silicon bipolar junction transistor 60 years ago, a whole array of silicon power semiconductor devices have been developed and commercialized. These devices enable power electronics systems to reach ultrahigh efficiency and high-power capacity needed for various smart grid and renewable energy system applications such as photovoltaic (PV), wind, energy storage, electric vehicle (EV), flexible ac transmission system (FACTS), and high voltage dc (HVDC) transmission. In the last two decades, newer generations of power semiconductor devices based on wide bandgap (WBG) materials, such as SiC and GaN, were developed and commercialized further pushing the boundary of power semiconductor devices to higher voltages, higher frequencies, and higher temperatures. This paper reviews some of the major power semiconductor devices technologies and their potential impacts and roadmaps.