Power Applications Research Articles

A Hybrid CMOS Digital-to-Analogue Converters Design for High Resolution SAR ADC

The paper describes the design and implementation of a 14-bit differential Digital-to-Analogue Converter (DAC) based on the Silterra 0.18µm Complementary Metal-Oxide-Semiconductor (CMOS) process to be established in a Successive Approximation Register (SAR) Analogue-to-Digital Converter (ADC) for the purpose of high-resolution, high accuracy and low power applications. The proposed differential DAC aims to eliminate the issue of stringent matching requirements imposed on high-resolution DACs while leveraging both linearity performance and power consumption parameters at a balanced point. The overall differential circuit consists of two parallel single-ended DACs that utilize a 4-bit Capacitor DAC (CDAC) and 10-bit Resistor DAC (RDAC) on each end, thereby establishing a hybrid-based architecture. Furthermore, the authors illustrate the proposed switching procedures applied to the sub-DAC circuits to ensure a low-power design is established. The new method effectiveness evaluation is confirmed by detailed transient simulations implemented on the DAC where the circuit performs the required conversions at a maximum conversion frequency of 2.5 MS/s with a peak power consumption of 0.1496mW for the standard voltage supply of 2.1V. Meanwhile, the schematic and post-layout simulations performed on the DAC registers peak DNL errors of -0.1612 and -0.8272, respectively. New research results depict performance improvements in terms of resolution and power consumption which facilitates the DAC implementation in contemporary electronic devices such as microcontroller peripherals and audio amplification devices. The overall deigned circuit is capable of achieving the desired 14-bit digital-to-analogue conversions under the CMOS 0.18µm technology, proving the DAC’s high-resolution efficacy.

An Excel/VBA Teaching-Learning Solution of Velocity Triangle Analysis of Hydraulic Turbines

Abstract :This study reports an investigation into the use of computational techniques applied to selected Turbo machinery problems. Students in their third year of a B.S./ B.Tech in Mechanical Engineering program often focus on this topic. As a result of being exposed to an overwhelming quantity of hypothetical ideas, loads of recipes, and references from information handbooks, students sometimes become overwhelmed during lessons on Turbomachinery. An intuitive learning scenario, such as a computerized setting, can be useful in some circumstances. Thus, computer-based exercises are essential to improve dynamic learning. This study will present an alternate technique of demonstrating the turbo machinery analysis using Excel/VBA. The classroom isn't the only setting where a powerful computer application can alter the way subjects are learned and homework is completed. Both students and teachers can benefit from the introduction of this technology. Students will benefit from having this tool available because it will eliminate the need for lengthy calculations and allow them to easily observe the effects of changing values on various variables, thereby improving their understanding of the subject matter and increasingtheir interest in and enthusiasm for studying it. Further, it will aid educators in conveying a variety of turbomachinery ideas to their students. In addition, students can use these resources in the project's design phase. This program can do more than just solve the equations; it can also tell you how the various parameters influence the forces. This means that students can complete as many calculations as they need with the touch of a button, without the risk of making a mistake or growing bored with the process. Keywords : Computational tool; engineering tool; Excel/VBA; innovative pedagogy; turbomachinery tool.

Ternary arithmetic and logic unit with carbon nanotube-based field-effect transistors for ultra-low power and high-speed applications

<span>The number of consumers for different applications has expanded tremendously as a result of the growth of consumer electronics-related applications in numerous sectors. Customers often need high-speed applications that use a minimal amount of power for a variety of applications like signal processing, picture processing, communication systems, and so on. The speed of a ternary logic-based design might be greater than that of a binary logic-based one. In this study, a novel architecture for arithmetic and logic units (ALUs) is proposed. The design makes use of ternary logic. In order to accomplish both low power consumption and high performance, methodologies for designing carbon nanotube-based field-effect transistors (CNTFETs) are employed. The method that has been suggested is able to carry out operations such as addition, subtraction, multiplication, reasoning, and comparison. After developing the recommended model, it is compared to earlier designs for power delay product (PDP), average power consumption, and maximum delay duration. The simulation findings show that the carbon nanotube field effect transistors (CNTFET) based ternary ALU circuits outperformed conventional ternary full adder circuits. The suggested design had a delay time of 13.94 ps and a PDP of 5.32 aJ, while the old design had a delay time of 17.67 ps and a PDP of 51.38 aJ.</span>

Discontinuous PWM Technique With Reduced Low-Order Harmonic Distortion for High-Power Applications

The modulation techniques used in high power applications have to generate high quality waveforms with reduced switching losses. As an attractive alternative, Discontinuous PWM (DPWM) techniques present lower device switching frequencies than conventional continuous PWM methods lowering the converter switching loss. Considering the same cooling system, this allows to increase the carrier frequency of DPWM methods displacing the main switching harmonics to higher frequencies. As a main drawback, when low carrier to fundamental ratios are used, DPWM methods present some undesired low-order harmonics that are required to be filtered. This paper presents a low-order harmonic minimization method for synchronous DPWM methods by modifying the conventional modulating reference to limit low order harmonics amplitude, while keeping the same effective switching frequency and thus limited switching losses.

A Design Methodology for High-Voltage, Highly-Integrated Switched-Capacitor Power Converters, and Implementation At 48 V-12 V, 23 W/cm$^{3}$ and 93.5% Peak Efficiency

In this work a design methodology and key considerations for high-voltage and highly-integrated switched-capacitor power converters is presented. The design methodology describes the power losses in high-voltage applications, where switching losses and gate-driver losses start becoming dominant compared to fully integrated, low voltage and low power applications. The design methodology is applicable for any highly-integrated switched-capacitor topology. To verify the design methodology a 48 V-12 V ladder switched-capacitor power converter in a 180 nm SOI BCD process, with external capacitors is implemented. The floating gate-drivers and a clock controller responsible for the power switch control are also presented. The peak efficiency of the proposed power converter is measured to be 93.5 %, and 24.5 W maximum output power, resulting in a power density of 23 W/cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> .

Mathematical Formulation and Experimental Evaluation of Efficient 8-Way Microwave Radial Power Combiner for High Power Applications

Mathematical Formulation and Experimental Evaluation of Efficient 8-Way Microwave Radial Power Combiner for High Power Applications

Toward assimilation of acoustic travel times into an ocean state estimate

Direct ocean observing systems are a scarce set of data that build the backbone for understanding the current state of the ocean. These systems are limited in areas of high variability in temperature and salinity. Pioneering work of Wunsch (1977) proposed efforts to extract detailed hydrographic information using sound propagation through the ocean, providing the scaffolding to improve our understanding of the ocean's interior. The integrated nature of such measurements makes acoustic thermometry a powerful application for monitoring regional to basin-averaged hydrographic changes in the ocean, a measurement that is difficult to achieve by individual “point” measurements (moorings, ship-borne CTD casts, or autonomous floats) alone. This work models acoustic travel times corresponding to eigenrays between a fixed source and receiver from an evolving ocean state. Inclusive computation of acoustic travel times within a dynamically evolving modeled ocean state provide a novel approach to model data comparison within a general ocean circulation model. An adjoint assimilation framework combines observations with numerical models to estimate and update oceanic state variables Forget et al. (2015). This process provides the necessary operators for model data comparison of ocean acoustic observable quantities within a consistent state estimation framework allowing for data assimilation from acoustic tomography measurements.

Correlating the microstructure with magnetic properties of Ti-doped high-frequency MnZn ferrite

In this study, high-frequency MnZn ferrites are prepared for power applications at 10 MHz using solid-state reaction method. The sample doped with 3000 ppm TiO2 yields the optimal comprehensive magnetic properties, with an initial permeability of 792, power loss of 415 kW/m3 (10 MHz, 5 mT, 25 ℃), and saturation induction of 460 mT. This indicates significant progress compared to previously reported results. The mechanisms of property optimisation, microstructure and domain structure evolution also discussed with TiO2 doping. The precipitation of Ti at the grain boundary can promote a high-density microstructure and favour the formation of magnetic monodomain in MnZn ferrites. Our results elucidate the correlations between microstructure, domain structure, and high-frequency performance, and present a potential roadmap for the development of high-frequency soft magnetic ferrites.

A Review on Thermophotovoltaic Energy Conversions and its Space Power Applications

Thermophotovoltaic (TPV) system coverts heat radiations from various sources like Thermophotovoltaic (TPV) system coverts heat radiations from various sources like combustion of fuels, industrial waste heat and nuclear energy into electricity. To fulfil the demand of energy TPV is an alternate, can enable approaches to energy storage and conversion. The TPV model consists of multiple arrays of TPV cells, an emitter, a radiator and a filter. one of the important advantages of TPVs are the high efficiencies and direct conversion of DC power. This paper presents the research being conducted till date in the field of Thermophotovoltaic cell and space applications of TPV cells. We have Thermophotovoltaic has been regarded as an energy substitute in radioisotope deep space power system for thermoelectric. TPV provides outstanding potential improvement in mass specific power as well as in efficiency. TPV system also proposed for inner planetary solar system. This idea leads TPV capability to store energy in the form of heat energy rather than electrical energies which is common in photovoltaic system. The current effort to derive the demonstration of efficiency conversion up to 19% and it enhances the specific power W/kg at the system level. Next generation TPV concepts are also reviewed in order to explore the future space power application. The application of TPV that includes radioisotope Thermophotovoltaic (RTPV) and solar Thermophotovoltaic (STPV) plays a vital role in deep space powered systems.

The Relationship Between Loneliness and Nomophobia in Nursing Students

Purpose: This study aims to determine the relationship between loneliness and nomophobia among S1 nursing students at STIKes Muhammadiyah Ciamis. Methods: The method used in this research is quantitative research with a correlational approach. The population in this study was 132 undergraduate nursing students at STIKes Muhammadiyah Ciamis. Sampling is done using the G*Power application. The number of samples in this study was 42. The research was conducted on March 28–29, 2023. Results: The results showed that the picture of loneliness in students mostly experienced moderate loneliness, as many as 20 respondents (47.6%). The picture of nomophobia students mostly experienced moderate nomophobia; as many as 17 respondents (40.5%) The results of the data analysis show a p-value of 0.692 &gt; 0.05. Conclusions: This study concludes that there is no relationship between loneliness and nomophobia among S1 nursing students at STIKes Muhammadiyah Ciamis.

The Relationship Between Vision And Ability To Activity In Post Cataract Surgery Patients At Pandega Hospital, Pangandaran District

Purpose: This study aims to determine the relationship between loneliness and nomophobia among S1 nursing students at STIKes Muhammadiyah Ciamis. Methods: The method used in this research is quantitative research with a correlational approach. The population in this study was 132 undergraduate nursing students at STIKes Muhammadiyah Ciamis. Sampling is done using the G*Power application. The number of samples in this study was 42. The research was conducted on March 28–29, 2023. Results: The results showed that the picture of loneliness in students mostly experienced moderate loneliness, as many as 20 respondents (47.6%). The picture of nomophobia students mostly experienced moderate nomophobia; as many as 17 respondents (40.5%) The results of the data analysis show a p-value of 0.692 &gt; 0.05. Conclusions: This study concludes that there is no relationship between loneliness and nomophobia among S1 nursing students at STIKes Muhammadiyah Ciamis.

(Invited) Selective Area Growth, Etching, and Doping of GaN By MOCVD for Power Electronics

The lack of selective-area doping technique in GaN greatly hinders the demonstration of sophisticated device structures for high power application. We explored the possibility of using selective-area etching followed by selective area growth to achieve SAD. For the etching step, we explored the in-situ TBCl etching, where we achieved controlled etch rate and smooth trenches. The TBCl etching was proven to be a low-damage etching process compared to the conventional dry etching. Moreover, selective area growth of p-GaN in a patterned trench was analyzed by atom probe tomography (APT). We found Mg atoms cannot diffuse on the GaN surface, which led to an observed inverse proportionality between Mg concentration and local growth rate. However, it was discovered that Mg precursors, like Ga, exhibit inter-trench diffusion through the gas phase.

Efficient High Temperature PEMFC Metallic Stack

The benefit of high temperature (HT) polymer electrolyte membrane fuel cells (PEMFCs) is very high for high power applications. They can be used in stationary and portable power devices combining the advantages of the PEM type cells (flexibility in dynamic operation, compactness) and high temperature operation (elimination of fuel humidification and carbon monoxide clean up). This work focuses on the development, construction and testing of an efficient all-metallic HT-PEMFC stack with 1kWe power output. The proper polymer electrolytes selection has given the possibility of operating the stack within the range of 160-190oC. The Membrane-Electrode-Assemblies (MEAs) and all of the stack’s components were designed and prepared in-house. There are many parameters that affect the fuel cell stack characteristics and performance such as the materials, components’ design and proper assembly of the stack, as well as the operating conditions. The electrical efficiency of the stack was 50% with power output of 1070 W and a power density of about 0.18 W/cm2 at 180°C under the feed of pure H2. With reformate hydrogen feeds, the stack reached the same performance.

Thermal performance of energy barrettes in an urban environment

Thermal performance of energy barrettes in an urban environment

Hydrogen Storage with Aluminum Formate, ALF: Experimental, Computational, and Technoeconomic Studies.

Long-duration storage of hydrogen is necessary for coupling renewable H2 with stationary fuel cell power applications. In this work, aluminum formate (ALF), which adopts the ReO3-type structure, is shown to have remarkable H2 storage performance at non-cryogenic (>120 K) temperatures and low pressures. The most promising performance of ALF is found between 120 K and 160 K and at 10 bar to 20 bar. The study illustrates H2 adsorption performance of ALF over the 77 K to 296 K temperature range using gas isotherms, in situ neutron powder diffraction, and DFT calculations, as well as technoeconomic analysis (TEA), illustrating ALF's competitive performance for long-duration storage versus compressed hydrogen and leading metal-organic frameworks. In the TEA, it is shown that ALF's storage capacity, when combined with a temperature/pressure swing process, has advantages versus compressed H2 at a fraction of the pressure (15 bar versus 350 bar). Given ALF's performance in the 10 bar to 20 bar regime under moderate cooling, it is particularly promising for use in safe storage systems serving fuel cells.

Improved GaN-based Current Aperture Vertical Electron Transistor (CAVET)

The objectives of this research are to improve and optimize a vertically structure HEMT device based on AlGaN/GaN heterojunctions. This novel proposed structure with double gate command would allow for a better dispersion of the electric field, with peaks lower and farther from the surface than a lateral structure. The research focuses on estimating the performance of a GaN-based vertical structure called a "Current Aperture Vertical Electron Transistor (CAVET)" that combines a two-dimensional electron gas (2DEG) and a vertical structure with technology, operation, settings, and performance that can be seen in power applications. Performance operating at high frequencies and low power loss consumer, a device that will, therefore, lead function to best in electrical power and higher system efficiency with IDss equal 0.95 A, -6 V for pinch-off, fT/fMax are 110/250 GHz and 14 % for Drain-lag.

Active Thermal Control in Neutral-Point-Clamped Multilevel Converters Based on Switching-Cell Arrays

Neutral-point-clamped multilevel converters are a suitable solution to the implementation of low–medium voltage and power applications at present, thanks to their intrinsic superior voltage and current quality. The conventional configurations of these converters present uneven power loss distribution, causing thermal stress in some power semiconductors, which weakens the power converter reliability. To overcome this, an implementation of the neutral-point-clamped multilevel converter based on a switching-cell array is introduced, adding redundant conduction paths on one side and more options to distribute the switching losses on the other side. An active thermal control is proposed to balance the temperature distribution in the converter. A four-level converter has been implemented to evaluate the proposed solution. The experimental results show that the proposed implementation and active thermal control presents an enhanced temperature distribution in the converter and, therefore, reduced thermal stress and better reliability.

Predicting and understanding corrosion in molten chloride salts

Molten chloride salts are stable at higher temperatures than many other salts, including nitrate salts, and are thus promising for heat transfer and/or thermal energy storage in concentrating solar power, nuclear power, and other thermal energy storage applications. However, corrosion in molten chloride salts remains a significant problem. While many studies have been devoted to evaluation of corrosion, we find that a comprehensive method for predicting corrosion in molten chloride salts is lacking. Here, we present an evaluation of corrosion in molten chloride salts using Ellingham diagrams and chloride-oxide stability diagrams, which enable prediction of alloy performance in molten chloride salts and allow corrosion results to be interpreted at a fundamental level.Graphical abstract

Big Data Processing over Cloud Computing Environment

The topics of this special paper are mainly devoted to the most recent research, development and applications in the field of cloud computing, big data processing in the various fields, e.g. Web blog, search engine, image processing, and industry. Among all of the submitted manuscripts, 15 papers were selected and included in this special paper. Creative thoughts and interesting inspirations are presented, discussed, and disseminated in this paper. First, there are three papers on the cloud architecture and optimization for big data processing. J. Peng, et al. discussed the problems of load balance for massive data processing on cloud considering the data processing efficiency and nodes’ capability. A load balance approach for massive data, based on the consistent hashing method, was presented to improve the data processing equalization and high processing efficiency. Large-scale sensor networks and internet of things are one of the most important application fields in big data. Y. Sun, et al. proposed a cloud computing system to support PaaS in energy power applications—PROXZONE. PROXZONE provides the cloud services uniform monitoring and authorization, and cloud message service, which can support good performance when dealing with big data. Meanwhile, S. Xu, et al. discussed an improved cooperative dynamic cluster model in multitasks mobile network, and proposed a cooperative message forwarding mechanism to improve the network performance.

Prevention of PID Phenomenon for Solar Panel Based on Mathematical Data Analysis Models

In recent years, the problem of potential-induced degradation (PID) phenomenon has been deeply associated with solar power issues because it causes serious power attenuation of solar panels and results in lowering its power generation efficiency. Thus, effectively identifying the PID problem from insights of industry data analysis to reduce production costs and increase the performance of power generation is an interesting and important subject for the solar power industry. Moreover, by the traditional standard rule (IEC62804) and the condition of a 96 h testing time, the costs of testing time and assembling materials against PID are very high and must be improved. Given the above reasons, this study proposes a hybrid procedure to organizes four mathematical methods: the mini-module testing, solar cell testing, a settling time, and a neural network, which are named as Method-1–Method-4, respectively, to efficiently solve the PID problem. Consequently, there are four key outcomes from the empirical results for solar power application: (1) In Method-1 with a 96 h testing time, it was found that the large module with higher costs and the mini module with lower costs have a positive correlation; thus, we can replace the large-module testing by the effective mini module for lower cost on module materials. (2) In Method-2 with a 24 h testing time, it was also found that the mini module and the solar cell are positively correlated; this result provides evidence that we can conduct the PID test by the easier solar cell to lower the costs. (3) In Method-3, the settling time achieves an average accuracy of 94% for PID prediction with a 14 h testing time. (4) In Method-4, the experimental result provides an accuracy of 80% when identifying the PID problem with the mathematical neural network model and are obtained within a 2 h testing time. From the above results, these methods succeed in reducing cost of materials and testing time during the manufacturing process; thus, this study has an industrial application value. Concurrently, Method-3 and Method-4 are rarely seen in the limited literature review for identifying PID problem; therefore, this study also offers a novel contribution for technical application innovation.