Efficient Power Supply Research Articles

Regulation of feeding part of complex of vibroacoustic diagnostics of rotary units of rolling stock

The article deals with the study of parameters of power supply control systems for the position of non-disassembly vibroacoustic diagnostics of rotary units of rolling stock. It is assumed that the power sources transmit constant electricity to bring the traction motors of electric locomotives and electric trains into rotation with the required frequency at the position of non-disassembly diagnostics of bearings. Experiments were performed following the MatLab/Simulink software. Analytical methods are used to determine the parameters of traction motors of electric rolling stock according to the program and the parameters of the controlled part as the power factor of various power supply options. The energy indicators of electric traction motors of electric rolling stock were determined in tabular and analytical forms, controlled parameters with different power coefficients of power sources. Based on the assessment of the energy indicators of various power supply options, it is concluded that it is advisable to use a circuit with a pulse converter in the position of vibroacoustic diagnostics of rotary assemblies. A variant of an energy–efficient power supply for non-disassembled vibroacoustic diagnostics is proposed, including an uncontrolled semiconductor rectifier and a pulse converter executed on an IGBT transistor. A radical way to increase the power factor of the power supply is using pulse voltage regulation.

New Trends and Prospects for Developing Local Power Sources Based on Fuel Cells and Power Storage Units for Critical Infrastructure Customers

A reliable and efficient power supply for critical infrastructure customers is key to ensuring energy security. Critical infrastructure requires local power sources. Currently, performance requirements for such sources have significantly increased. Apart from high energy efficiency, important requirements include quick start-up time, small size, environmental friendliness, low noise, etc. These may be provided by fuel cells, which are considered the most prospective sources of electric power. However, it is necessary to overcome a number of obstacles limiting fuel cell efficiency in power supply systems for critical infrastructure customers. This paper presents the results of design analysis in the field of fuel cell, hydrogen conversion and power storage technologies. An assessment is given of promising studies aimed at combining the abovementioned technologies to create local power sources to ensure reliable power supply to critical infrastructure objects.

Analysis of the structure of generating capacity and dynamics of electricity consumption in Sredne-Kamchatsky isolated power hub

THE PURPOSE. To examine the features of the location and the overall structure of theSredne-Kamchatskyisolated power hub. To considerthe structure of installed electric capacity and the composition of generating equipment of power plants in the mentioned power hub. To determine the composition and characteristics of the electric grid economy. To analyze and determine the main indicators of electricity consumption and capacity dynamics of the hub. To perform an analysis of the existing balance of power and electric energy, to determine the main technical and economic parameters of the power supply. To consider options for the power supply system development including on the basis of renewable energy sources. METHODS. When solving this problem, we usedmethods of mathematical processing of statistical data and methods of normative forecasting. RESULTS. We considered the special featuresof generating capacities and network infrastructure development,the issues ensuring the long-term and medium-term demand for electric energy and capacity, the formation of stable and favorable conditions for attracting investment in the construction of electric power facilities.The study calculated the current and prospective balances of electricity and capacity in the discussed power hubbased on the analysis of the energy structure of an isolated power unit and the dynamics of electricity consumption. CONCLUSION. Any failure in an isolated system leads to dangerous crisis phenomena and significant economic losses. Thus it is important to provide reliable and efficient power supply to energy isolated territories. The presented comprehensive assessment of the state of the electric power industry in the isolated Sredne-Kamchatsky power plant allows us to predict the prospects for its development within the framework of the overall development of the electric power complex of the Kamchatka Territory.

Design and Implementation of Multi-output Flyback Switch Power Supply

The switching power supply with flyback topology type has the advantages of easy design, lightweight, and high efficiency, and it is widely used in occasions with low power and multiple outputs. In order to solve the problems of low efficiency and low output precision of switching power supply in the current market, this paper proposes an improved 90~264Vac to +5V, +15V, -15V three-way output flyback with a power of 43.5W. The experimental test results show that the proposed switching power supply has the advantages of strong anti-interference, strong robustness, high efficiency, and low cost, and it can be widely used in various electronic devices.

In-situ fabrication of superhydrophobic surface on copper with excellent anti-icing and anti-corrosion properties

The accumulation of ice on electrical construction works not only leads to the reduced efficiency of power supply and heat exchangers, but also increases the energy losses and even brings about serious disasters. Therefore, it is essential to reduce or eliminate the issue of ice accumulation on metal constructions. Nowadays, superhydrophobic surfaces have received lots of attentions for their outstanding hydrophobicity. In this study, Cu(OH)2 nano grass was firstly in-situ constructed on copper surface via simple anodization, then superhydrophobic CuO nano needles were obtained after the dehydration of Cu(OH)2 and modification with fluoro-alkyl silanes. The results showed that when the anodic oxidation temperature was 20 °C and the current density was 2 mA·cm−2, nano-needle-like multistage micro-nano structures can be obtained. The as-prepared superhydrophobic surface showed the water contact angle as large as 162° and sliding angle lower to 4°. Additionally, the as-prepared superhydrophobic surface displayed outstanding anti-icing property, delaying icing substantially even under − 10 °C environment regardless of droplet volume and type. Moreover, it also revealed good anti-corrosion property with a corrosion current density of 2.2 × 10−8 Ω·cm2 and the corrosion resistance of 1.55 × 106 Ω·cm2 which is about three order of magnitudes than that of bare copper. We prospect that this easily prepared surface can provide a solution of anti-icing and anti-corrosion for electrical construction works and large-scale metals.

Predictive Data Analytics for Electricity Fraud Detection Using Tuned CNN Ensembler in Smart Grid

In the smart grid (SG), user consumption data are increasing very rapidly. Some users consume electricity legally, while others steal it. Electricity theft causes significant damage to power grids, affects power supply efficiency, and reduces utility revenues. This study helps utilities reduce the problems of electricity theft, inefficient electricity monitoring, and abnormal electricity consumption in smart grids. To this end, an electricity theft dataset from the state grid corporation of China (SGCC) is employed and this study develops a novel model, a mixture of convolutional neural network and gated recurrent unit (CNN-GRU), for automatic power theft detection. Moreover, the hyperparameters of the proposed model are tuned using a meta-heuristic method, the cuckoo search (CS) algorithm. The class imbalance problem is solved using the synthetic minority oversampling technique (SMOTE). The clean data are trained and then tested with the proposed classification. Extensive simulations are performed based on real energy consumption data. The simulated results show that the proposed theft detection model (CNN-GRU-CS) solved the theft classification problem better than other approaches in terms of effectiveness and accuracy by 10% on average. The calculated accuracy of the proposed method is 92% and the precision is 94%.

Electrochemical enhanced betavoltaic cells based on ZrO2@TiO2 nanorod arrays with type-I band alignment

Direct energy conversion from beta radiation to electricity using betavoltaic effect is a promising energy conversion technology for a long-time and highly efficient power supply. This work presents an electrochemical betavoltaic cell (EBC), consisting of a beta-anode with TiO2 nanorod arrays (TNRAs) modified with ZrO2 nanoparticles, a polyiodide (I−/I3−) electrolyte, and a 63Ni/Ni counter electrode. Free-standing TNRAs structures were fabricated using hydrothermal method and post-annealed in Ar atmosphere to enable a rutile TiO2 material with excellent electrochemical performance. Monte Carlo (MC) method was used to determine the optimum length (∼2.5 μm) of the TiO2 nanorods. Investigation on ultraviolet photoelectrochemical performance of EBCs was used to evaluate and optimize the content of ZrO2 (thickness of ∼10 nm) modified on the TNRAs. The EBCs demonstrated an energy conversion efficiency of 9.27% with an open-circuit voltage of 0.276 V and short-circuit current density of 1.041 μA·cm−2 when using a 10 mCi 63Ni source. The enhanced performance can be ascribed to the three-dimensional ZrO2/TiO2 heterojunction with a large specific area in favor of the interface carrier transfer as well as the suppression of carrier recombination through the type-I band barrier, effectively promoting the electrochemical redox reaction.

INVERTER MODELING IN IMPROVING THE ENERGY EFFICIENCY OF A MOBILE UNINTERRUPTED SUPPLY SOURCE

In the work in the MATLAB program, an IGBT-transistor inverter was modeled to improve the energy efficiency of a mobile uninterruptible power supply. In order to improve the efficiency of the uninterruptible power supply, its principal and structural diagrams have been developed.

A green energy circular system with carbon capturing and waste minimization in a smart grid power management

Sustainable electricity production is an energy-efficient strategy aimed at both economic progress and environmental conservation. The power generation sector is the major contributor to global emissions and waste. The scope of circular economy in the power production sector with investments in waste minimization and emission reduction was not discussed in previous studies. In this context, a circular sustainable smart electric supply chain system is introduced in this paper with an aim of maximizing the profit with the minimum amount of emissions and waste generated from the power generation units. The power plant in this system consists of four power generation units that generate electricity from coal, waste, wind, and solar plants. A smart grid management system is used in this system for an efficient power supply according to the demands of the customer, and it enhances the system to distribute the power from renewable energies. In this system, the carbon dioxide from the thermal plants is captured and converted to natural gas to reduce emissions. Municipal and industrial waste is transformed into composite fuel to generate electricity. The profit for each unit and the customer’s demand for electricity depends on the circularity index. Linear demand versus linear and logistical cases of unit profit was considered. This study theoretically and numerically maximizes the profit of the system with optimal power consumption, circularity index of electricity, and green and waste minimization investment as per the carbon cap policy. To find the optimal strategies for maximum profit, an algorithm was developed. Sensitivity analysis is done to determine the fluctuations in the profit, emission cost, waste cost, circularity index, and power consumption due to the variations in parameters. The wise allocation of power generation from each unit and reduce energy loss by installing efficient storage devices will result in a higher profit. A system with the high efficacy of green techniques to reduce emissions, a smart grid to minimize waste, higher taxes to regulate emissions, and a rise in the amount of production of electricity from renewable sources will result in a greener power system that gains more profit than conventional systems. The key findings state that electric supply chain systems can obtain a good profit in a more sustainable manner than conventional systems.

Development and research of uninterruptible power supply system for networks with supply voltage up to 24 V

Objectives. Due to the continuous rapid development of renewable energy sources, requirements for secondary power supply systems keep increasing from year to year. Productive uptime for end users is dependent on the efficiency and stability of the power supply system. Such systems should be able to distribute and store energy from renewable sources having various parameters and configurations. Therefore, the present work is aimed at developing technical solutions for efficient uninterruptible secondary power supply systems in low voltage DC networks.Methods. Advanced circuitry solutions are used for performing pulse conversions with high efficiency. The flexible hardware-software system is used for implementing the parameter control system.Results. An uninterruptible power supply for low-voltage DC networks is developed. The description of subsystems and calculations for all main elements including the power ones are given. Using a contemporary component base, the system prototype is assembled, configured, and measured by parameters. The presented solutions allow achieving the universality of the system in terms of the input and output voltage range. Support for the fast-charging Power Delivery protocol is integrated. As well as regulating the battery charging current and voltage, the Li+ battery charging controller permits changes in the number of chargeable cells. The monitoring and control unit monitors network parameters and controls the system automation. Using a microcontroller as the control device, it is possible to easily change control parameters by changing software settings. Dual redundancy of the module monitoring the built-in battery parameters is used to ensure the reliability and safety of system functioning. Support for the standardized I2C communication protocol with a separate power bus allows any necessary sensors to be connected for monitoring system parameters. External high-power devices controlled by a PWM signal may be added, if required. In the paper, the Li+ battery charging profile recommended by the manufacturer is provided.Conclusions. The designed system provides stable power supply to end users at a power consumption up to 40 W for at least 45 min. The automation demonstrates reliable operation.

Construction and performance analysis of a solar thermophotovoltaic system targeting on the efficient utilization of AM0 space solar radiation

Solar thermophotovoltaic (STPV) has great potential as efficient power supply source for spacecraft to meet the demand of spacecraft miniaturization. In this work, a novel space STPV system is proposed to achieve the efficient utilization of the AM0 space solar radiation. Metamaterial structures were designed and FDTD method is used to analyze their radiation regulation mechanism. A multi-layer cylindrical periodic structure is used as the absorber which realizes a total absorptance of 0.9283 to AM0 radiation. A cylindrical periodic structure is used as the emitter to reshape the broadband thermal radiation as narrowband to match with the Si/InGaAsSb tandem cell, which realizes a highest TPV efficiency of 51.36%. System performance analysis is conducted and the system presents a highest STPV efficiency of 40.86% and good adaptability under wide range of operating parameters, which reveals its great potential to realize the efficient utilization of AM0 solar radiation for space power supply.

Guest Editorial Special Issue on Power Electronics Systems for Aerospace Applications

Aerospace applications have been a major driver for the development of power electronics. The demand of light and efficient power supplies, common both for space and aeronautic applications, spearheaded the research and development efforts around switching mode power systems. Major seminal works in the field, such as those pioneered by Prof. R. D. Middlebrook, were developed under funding from National Aeronautics and Space Administration (NASA). Another example is that average current mode control or transconductance control was developed in the European Space Agency (ESA) laboratories while at the same time peak current mode control was invented in U.S. institutions.

Cooperation between Z.-T. Gramme and P.N. Yablochkov in the Field of Creating AC Generators (On the 175th Anniversary Since the Birth of P.N. Yablochkov)

The great invention of Pavel Nikolaevich Yablochkov and his vigorous activity turned mountains. Within a short period of time, electrical engineering has become a powerful driving force of world progress. The deeper we dive into the study of the Russian inventor’s history, the more of new facts and amazing aspects of his genius are revealed to us. Yablochkov’s candle operated on alternating current. The alternators that existed at that time became obsolete. New electrical machines were urgently needed. In the late 1870s, direct currents were mainly used in electrical engineering. P.N. Yablochkov had to make serious efforts to solve the problem of providing efficient power supply for his lamps. Cooperation of two great electrical engineers P.N. Yablochkov and Z.-T. Gramme led to the development of alternating current technologies and the development of the first two-phase generators, which formed the basis for the development of multiphase electric currents, an entire field in electrical engineering.

Модель совместной работы системы тягового и внешнего электроснабжения

Purpose: To improve record accuracy of external power supply network influence on the operation of traction power supply systems of industrial frequency AC. The article shows that existing mathematical models of traction and external power supply joint operation have sounding limitations. These limitations almost exclude the possibility of their practical use. At the same time, when projecting a new electrification, it is required to choose the most efficient external power supply scheme. At the exploitation of existing electrified sections, the necessity arises to assess equalizing current value during repairs in external power supply networks and to adopt a decision on changing power supply and sectioning schemes. Corresponding model is required to solve these tasks. Methods: Analysis of existing mathematical models and computer programs for joint calculation for traction and external power supply networks. Development of three-phase PU-generator models on the basis of EMF source behind an inductive resistance, development of three-phase and single-phase load models. Results: The article presents a description of a mathematical model implied to study the joint operation of 25 kV AC traction power supply systems and 110-750 kV power supply systems. The principles of building the model of three-phase and single-phase PU-generators on EMF source basis behind inductive resistance as well as the models of three-phase and single-phase loads are considered. Based on the given mathematical expressions, a computer model has been developed that allows analyzing the joint operation of three-phase external power supply networks and single-phase traction ones. The model is implemented in MATLAB-Simulink software package. Using this computer model, the influence of power flows through 110–330 kV network of Karelenergo and “FSK EAS” Public Companies on equalizing currents in the traction network of Knyazhaya — Idel section of Oktyabrskaya railway was analyzed. Practical importance: The reliability raise for traction power supply system operation at the expense of precise calculation of equalizing currents. Energy loss reduction in a traction network in account of traction network optimal power supply scheme choice.

High-Voltage Power Supply for High Repetitive Rate Marx Generator with Quasi-Resonant Zero-Current Switching Transistor Control Algorithm

Due to having a number of advantages, Marx generators are still the most widely used devices for generating high-voltage pulses in many fields of science and technology. To ensure their proper operation, especially when the generation of many frequent, highly repetitive pulses is required, a highly efficient high-voltage power supply is needed. The paper describes a specially developed power supply (input voltage 48 V DC, output voltage up to 50 kV) based on the conventional Full Bridge topology with two high-frequency high-voltage transformers and a 6-stage voltage multiplier. In order to avoid many problems caused by low coupling between primary and secondary windings of the transformers and the large parasitic capacitances of the secondary windings, a special quasi-resonant zero-current switching transistor control algorithm with variable switching frequency (dependent on output load) was developed. In the described method, the energy is supplied to the transformer in short pulses, when a pair of diagonal transistors of the full-bridge converter were turned on. Then, the freewheeling state is maintained until all of the energy stored in the leakage inductance of the transformer has been transferred to the secondary side, which means that the current in the primary windings drops to zero. This approach reduces energy losses, electromagnetic disturbances and prevents current distortion in primary winding.

A Petri Net-Based Power Supply Recovery Strategy for the Electric Power System of Floating Nuclear Power Plant

Floating nuclear power plants contain sensitive loads of nuclear reactors. After equipment faults, fast and efficient power supply recovery should be realized. To realize the unified analysis of system topology and power flow distribution, a power supply recovery strategy based on Petri nets is proposed. Considering that systems of different voltage levels cannot be connected instantaneously, a two-stage power supply recovery mode is adopted. Emergency power supply is put in first, and then the whole network is reconstructed. In the network reconstruction process, load transfer is realized through switching the transformation to redistribute the load of each switchboard and adjust the power output of each power source. Corresponding to the Petri net model, the above process is similar to the dynamic transmission process of a token in each library by firing the transition. Therefore, the topological model of system is constructed based on the Petri net, and a power flow analysis is proposed through its dynamic updating mechanism. The objective function of the network reconstruction is established by integrating load recovery amount, switch operation cost and generator operation efficiency, and the optimal switching state combination scheme that satisfies the system constraints is obtained by the multi-population genetic algorithm (MPGA). Simulation results show that the proposed method can provide complete power supply recovery.

Evaluation method of a new power system construction based on improved LSTM neural network

The evaluation of new power system construction is the research foundation for improving the flexible regulation ability and comprehensive operational efficiency of new power systems, and achieve the comprehensive goals of safe power supply, green consumption, and economic efficiency. However, the existing research on the evaluation index system of new power system construction can not fully reflect the main objectives of new power system construction. Therefore, this paper first develops a source-load and green-intelligence multi-level and multi-dimensional evaluation system for new power system construction from source-load side equipment, green power, reliable power supply, and intelligent power consumption. Secondly, a hybrid optimization algorithm is proposed based on fluid search algorithm (FSO) for improving the Long Short-Term Memory (LSTM) neural network parameter updating method. Then, the improved LSTM neural network is applied to the construction evaluation of the new power system. Finally, the simulation results show that the evaluation error of the new power system construction evaluation method is 0.0063, which has a high evaluation.

Feasibility Study and Techno-Economic Analysis of Solar PV-Biomass Hybrid Power System: A Case Study of Kajola Village, Nigeria

Efficient and sustainable electric power supply is needed for effective healthcare delivery, provision of quality education system, and building of impactful social/human infrastructures. Unrestricted access to reliable and affordable electricity will improve people's welfare and enhance quality healthcare delivery globally. The need to reduce the harmful impact of Greenhouse gas emissions along with its fossil fuel emissions have necessitated the need for the numerous research interests in low-carbon power generation systems. The feasibility and techno-economic analysis of an off-grid Solar Photovoltaic (PV)/Biomass (BG)/Diesel (DG)/Battery (BB) hybrid system for a rural village-Kajola, Nigeria was conducted in this paper. Renewable energy sources (RES) parameters such as irradiation data, biomass resources, and DG parameters were collected from National Aeronautics and Space Administration (NASA)’ database, Ekiti State Ministry of Agriculture and manufacturers’ price lists respectively. The load demand assessment of the area was conducted and analyzed through the use of questionnaires. All the relevant data collected were used as input into the HOMER software. The optimal configuration is the PV-BG-BB combination. The Levelized Cost of Energy (COE) is $0.178/ kWh, with renewable energy fraction (RF) of 100%. This means that nearly all of the energy used by the hybrid system to meet the load is generated from renewable sources. The proposed solar PV/Biomass generator/Battery bank hybrid energy system can supply electricity to the village under consideration at an hourly average of approximately 52.7 kW and with an average daily energy need of 483.71 kWh. The study will serve as a template for all electric power system stakeholders and potential investors on the feasibility and optimal design of hybrid renewable energy system for rural electrification.

Research on Financial Strategy and Financial Capability of Grassroots Power Supply Enterprises Based on Stochastic Matrix Model

On the basis of the generation, evolution, and development of the basic power supply enterprise’s financial core competence, this article determines the connotation and essence of the basic power supply enterprise’s financial core competence, so as to play a guiding role in fully and correctly grasping the basic power supply enterprise financial core competence. This article focuses on the formation mechanism and factors of the financial core competence of grassroots power supply enterprises and reviews the latest research hotspots and their theoretical significance in academia. By applying the random matrix model to evaluate the core financial capabilities of grassroots power supply enterprises, it proposes a path for cultivating and improving the core financial capabilities of grassroots power supply enterprises. Through a detailed and powerful discussion, it is possible to effectively improve the financial management efficiency of grassroots power supply enterprises and quickly adapt to the needs of market changes, so as to meet the interests of relevant stakeholders of grassroots power supply enterprises as much as possible. Considering the market competition environment, it is found that the positive relationship between corporate responsibility information disclosure and the degree of earnings management is only significant in low-competitive markets, which also shows that with the intensification of market competition, the degree of information asymmetry decreases. The ability of power supply is also increasing, which will weaken the mechanism of grassroots power supply enterprises to conceal earnings management behavior through corporate responsibility information disclosure. The results show that corporate responsibility information may become a tool to cover up the management of grassroots power supply enterprises to manipulate earnings and reduce the quality of earnings reports, and this behavior will be different in grassroots power supply enterprises with different characteristics and external environments. This will help to form an objective understanding of corporate responsibility information disclosure behaviors, identify the motives of grassroots power supply companies’ responsible behaviors for regulators, standardize corporate responsibility disclosure norms, and take differentiated measures for different situations.

Applying Neural Network And Levenberg - Marquardt Algorithm for Load Forecasting in IA-Grai District, Gia Lai Province

Electrical energy is fundamental to the life and economic development. Accompany by the increasing demand for electricity by people and businesses, the electricity industry must always ensure sufficient supply for production activities. This poses an urgent need to have an accurate load forecasting tool for electricity production and distribution strategy. If the demand forecast is lower than the reality, the phenomenon of power supply shortage will occur. While if the forecast exceeds the demand for use by people and businesses, it will cause economic losses because it must mobilize power sources by using a backup as a diesel generator. For these reasons, the problem of electrical load forecasting becomes very important in terms of efficient power supply. In this paper, a load forecasting tool using Neural Network and Levenberg - Marquardt algorithm is presented.