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1
Szcześniak, Paweł. "Comparison of control methods for a dynamic voltage restorer using a three-phase matrix converter". SIMULATION 92, n. 12 (14 ottobre 2016): 1053–63. http://dx.doi.org/10.1177/0037549716673203.
Abstract (sommario):
A dynamic voltage restorer (DVR) is used in a power distribution system to protect sensitive loads against voltage disturbances. The commonly used DVR system contains a converter with direct current (DC) link and energy storage elements. The DC energy storage part of the system is the most expensive element and has a large value. As an alternative, therefore, DVR systems can use alternating current AC/AC converters without DC energy storage. This paper presents the properties of a DVR system based on a direct matrix converter using three control methods: in-phase, pre-sag, and energy-optimal. The paper defines basic mathematical relationships and static characteristics and describes the range of voltage compensation by use of the described compensation methods. Simulation results are obtained and presented in order to verify the correctness of the compensation. The features of such a DVR system configuration are considered in the context of alternative applications for commonly used converters with DC-link energy storage power converters. Application of the matrix converter in electrical power systems is still not very popular, due to limited output voltage and the complex structure and process control. This article is an attempt to show the usefulness of the matrix converter in spite of its limitations and the complexity of the design.
2
Erat, Abdurrahim, e Ahmet Mete Vural. "DC/DC Modular Multilevel Converters for HVDC Interconnection: A Comprehensive Review". International Transactions on Electrical Energy Systems 2022 (8 settembre 2022): 1–49. http://dx.doi.org/10.1155/2022/2687243.
Abstract (sommario):
High voltage direct current (HVDC) technology is a key component in power systems owing to huge benefits such as long-distance power transmission, lower losses, asynchronous grid interconnections, controllability, system availability, and limited short-circuit currents. HVDC transmission is a cost-effective method of transporting huge amounts of power across long distances with little loss. It can also link asynchronous alternative current (AC) networks while balancing the grid. DC/DC converters are one of the most important components for HVDC power transmission, and DC/DC modular multilevel converters (MMCs) are the backbone of HVDC grid interconnections. The DC/DC MMC is a highly regarded converter architecture for medium/high-voltage DC grid interconnection. DC/DC MMC topologies play a key role in modern HVDC networks with varying voltage levels. This paper’s fundamental aim is to offer a recent comprehensive review of HVDC topologies, current DC/DC modular multilevel converter (MMC) topologies for HVDC interconnection, and DC/DC MMC control techniques.
3
Oni, Oluwafemi Emmanuel, Kamati I. Mbangula e Innocent E. Davidson. "A Review of LCC-HVDC and VSC-HVDC Technologies and Applications". Transactions on Environment and Electrical Engineering 1, n. 3 (30 settembre 2016): 68. http://dx.doi.org/10.22149/teee.v1i3.29.
Abstract (sommario):
High Voltage Direct Current (HVDC) systems has been an alternative method of transmitting electric power from one location to another with some inherent advantages over AC transmission systems. The efficiency and rated power carrying capacity of direct current transmission lines highly depends on the converter used in transforming the current from one form to another (AC to DC and vice versa). A well configured converter reduces harmonics, increases power transfer capabilities, and reliability in that it offers high tolerance to fault along the line. Different HVDC converter topologies have been proposed, built and utilised all over the world. The two dominant types are the line commutated converter LCC and the voltage source converter VSC. This review paper evaluates these two types of converters, their operational characteristics, power rating capability, control capability and losses. The balance of the paper addresses their applications, advantages, limitations and latest developments with these technologies.
4
Wang, Kai, Hai Shun Sun, Yu Hua, Yuan Liu, Wei Xing Lin e Cheng Hao Li. "Research on DC Voltage Control Strategies for Typical Four-Terminal HVDC System". Applied Mechanics and Materials 521 (febbraio 2014): 222–28. http://dx.doi.org/10.4028/www.scientific.net/amm.521.222.
Abstract (sommario):
The continuous development of alternative energy has put forward higher requirement for electricity transmission. To cope with its fluctuation characteristics, high voltage direct current (HVDC) technology has received more attention. Voltage Source Converter (VSC) based Multi-Terminal High Voltage Direct Current (MTDC) represents the future trend of HVDC technology. This paper mainly focuses on the control strategies of a four-terminal VSC based MTDC power transmission system. The operation characteristic of the system was studied, and the proposed two control strategies, master-slave control strategy and DC voltage droop control strategy, were verified through simulations. The latter control strategy was proved to be performing well under various conditions, including converter station disconnection and faults at AC side of the converter.
5
B. Balaji e J. D. Anunciya. "Model Predictive Control based Direct Matrix Converter fed Permanent Magnet Synchronous Machine drives for Traction and Electric Mobility Applications". ARAI Journal of Mobility Technology 2, n. 1 (15 gennaio 2022): 140–51. http://dx.doi.org/10.37285/ajmt.1.1.8.
Abstract (sommario):
There have been extensive research works going on electric mobility but most of these work and the existing electric mobility systems are battery-based DC systems. In some applications of electric mobility like traction and advanced technologies like electromagnetic induction charging, AC fed systems are employed due to the innate qualities of AC power transmission. Almost all the electric mobility systems we use are AC induction or permanent magnet machines. The conventional electric mobility systems including traction having AC as their energy source use two-stage conversion i.e. A fixed AC is converted to a fixed or variable DC link using a rectifier and finally, an inverter provides a variable AC in terms of frequency and magnitude according to the control algorithm. The two-stage conversion has its pros and cons but Matrix Converter (MC) will be a suitable and efficient alternative for AC fed AC motor drives. In the case of traction and other electric mobility applications, the load torque demand plays a significant role. The predictive control technique provides a suitable solution for these kinds of special drive applications due to their selective parameter control ability. Implementation of predictive control using a matrix converter is more effective than the conventional inverter fed drives, owing to the increased viability of matrix converter switching configurations. This paper discusses the mathematical implementation and comparison of Predictive Current Control (PCC) and Predictive Torque Control (PTC) with and without weighing factor for AC fed electric mobility applications. The efficacy of both the model predictive control techniques in concern of execution time, steady-state, transient, and dynamic conditions are analysed and validated along with the influence of diverse control variables in the cost function.
6
Vozikis, Dimitrios, Fahad Alsokhiry, Grain Philip Adam e Yusuf Al-Turki. "Novel Enhanced Modular Multilevel Converter for High-Voltage Direct Current Transmission Systems". Energies 13, n. 9 (4 maggio 2020): 2257. http://dx.doi.org/10.3390/en13092257.
Abstract (sommario):
This paper proposes an enhanced modular multilevel converter as an alternative to the conventional half-bridge modular multilevel converter that employs a reduced number of medium-voltage cells, with the aim of improving waveforms quality in its AC and DC sides. Each enhanced modular multilevel converter arm consists of high-voltage and low-voltage chain-links. The enhanced modular multilevel converter uses the high-voltage chain-links based on medium-voltage half-bridge cells to synthesize the fundamental voltage using nearest level modulation. Although the low-voltage chain-links filter out the voltage harmonics from the voltage generated by the high-voltage chain-links, which are rough and stepped approximations of the fundamental voltage, the enhanced modular multilevel converter uses the nested multilevel concept to dramatically increase the number of voltage levels per phase compared to half-bridge modular multilevel converter. The aforementioned improvements are achieved at the cost of a small increase in semiconductor losses. Detailed simulations conducted in EMPT-RV and experimental results confirm the validity of the proposed converter.
7
Gontijo, Gustavo, Songda Wang, Tamas Kerekes e Remus Teodorescu. "New AC–AC Modular Multilevel Converter Solution for Medium-Voltage Machine-Drive Applications: Modular Multilevel Series Converter". Energies 13, n. 14 (16 luglio 2020): 3664. http://dx.doi.org/10.3390/en13143664.
Abstract (sommario):
Due to its scalability, reliability, high power quality and flexibility, the modular multilevel converter is the standard solution for high-power high-voltage applications in which an AC–DC–AC connection is required such as high-voltage direct-current transmission systems. However, this converter presents some undesired features from both structural and operational perspectives. For example, it presents a high number of components, which results in high costs, size, weight and conduction losses. Moreover, the modular multilevel converter presents problems dealing with DC-side faults, with unbalanced grid conditions, and many internal control loops are required for its proper operation. In variable-frequency operation, the modular multilevel converter presents some serious limitations. The most critical are the high-voltage ripples, in the submodule capacitors, at low frequencies. Thus, many different AC–AC converter solutions, with modular multilevel structure, have been proposed as alternatives for high-power machine-drive applications such as offshore wind turbines, pumped-hydro-storage systems and industrial motor drives. These converters present their own drawbacks mostly related to control complexity, operational limitations, size and weight. This paper introduces an entirely new medium-voltage AC–AC modular multilevel converter solution with many operational and structural advantages in comparison to the modular multilevel converter and other alternative topologies. The proposed converter presents high performance at low frequencies, regarding the amplitude of the voltage ripples in the submodule capacitors, which could make it very suitable for machine-drive applications. In this paper, an analytical description of the voltage ripples in the submodule capacitors is proposed, which proves the high performance of the converter under low-frequency operation. Moreover, the proposed converter presents high performance under unbalanced grid conditions. This important feature is demonstrated through simulation results. The converter solution introduced in this paper has a simple structure, with decoupled phases, which leads to the absence of undesired circulating currents and to a straightforward control, with very few internal control loops for its proper operation, and with simple modulation. Since the converter phases are decoupled, no arm inductors are required, which contributes to the weight and size reduction of the topology. In this paper, a detailed comparison analysis with the modular multilevel converter is presented based on number of components, conduction and switching losses. This analysis concludes that the proposed converter solution presents a reduction in costs and an expressive reduction in size and weight, in comparison to the modular multilevel converter. Thus, it should be a promising solution for high-power machine-drive applications that require compactness and lightness such as offshore wind turbines. In this paper, simulation results are presented explaining the behavior of the proposed converter, proving that it is capable of synthesizing a high-power-quality load voltage, with variable frequency, while exchanging power with the grid. Thus, this topology could be used to control the machine speed in a machine-drive application. Finally, experimental results are provided to validate the topology.
8
Liu, Lei, Xiaopeng Li, Qin Jiang, Yufei Teng, Mingju Chen, Yongfei Wang, Xueyang Zeng, Yiping Luo e Pengyu Pan. "A Multi-Terminal Control Method for AC Grids Based on a Hybrid High-Voltage Direct Current with Cascaded MMC Converters". Electronics 12, n. 23 (27 novembre 2023): 4799. http://dx.doi.org/10.3390/electronics12234799.
Abstract (sommario):
The hybrid high-voltage direct current (HVDC) transmission system with cascaded MMC converters has become a promising alternative for possessing the technical merits of both line-commuted converter (LCC) and voltage source converter (VSC), resulting in favorable characteristics and potential control of good prospect. This paper pays heightened attention to the feasible power and DC voltage control modes of a hybrid HVDC system; characteristics of master–slave control show higher flexibility than the LCC-VSC HVDC system, which demonstrates that the exceptional potential can serve to stability support the AC power grids. To optimize the control effect, besides damping level to attenuate power oscillations, the robustness suitable for various faults is also considered to obtain a multi-objective control problem. A detailed solution is proceeding using the TLS-ESPRIT identification algorithm and H2/H∞ hybrid robust control theory. This motivates multi-terminal controllers in the LCC rectifier and MMC inverters, which immensely improve the stability of both sending and receiving girds at the same time. According to the parameters of the actual hybrid HVDC project, the simulation model is established in PSCAD v4.6.2 software, and proposed control methods have been verified to satisfy damping objectives and perform well in multiple operating scenarios.
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Quintero-Arredondo,, Jesus, e Ha Thu Le. "Medium Voltage Direct Current Distribution System for an Electric Vehicle Fast Charging Park". WSEAS TRANSACTIONS ON POWER SYSTEMS 18 (31 dicembre 2023): 412–25. http://dx.doi.org/10.37394/232016.2023.18.41.
Abstract (sommario):
There is an increasing shift towards the electrification of automobiles to meet zero-emission standards set by many nations. As electric vehicles become more common, their power demand on the power system becomes greater. A substantial modernization or upgrade of the current distribution power grid is required to meet such demand. Since most Level 3 fast chargers utilize DC power, medium voltage direct current (MVDC) provides a feasible alternative to the present AC distribution infrastructure. This study proposes an MVDC distribution model for powering a large EV park consisting of 40 EV charging stations with a 9.6-MW total power demand. Calculation and simulation are used to evaluate the model and compare it with an equivalent MVAC system. The outcomes show that implementing an MVDC distribution system is an efficient approach to meeting the increasing power demand for electric vehicles. The proposed 40-kV MVDC system power loss (13.1kW) is six times lower than that of the equivalent MVAC system (89.74kW). Further, since MVDC systems do not require AC step-down transformers and AC/DC converters at the equipment end, they can be a lower-cost option for powering large EV charging parks. The findings help enhance EV charging infrastructure, which expedites the adoption of EVs for reducing carbon emissions in the transportation sector.
10
K, JAGADEESH, e Ch Chengaiah. "Evaluation of PV-based Buck-Boost and SEPIC Converters for EV Charging Applications". Trends in Renewable Energy 10, n. 2 (2024): 159–69. http://dx.doi.org/10.17737/tre.2024.10.2.00168.
Abstract (sommario):
In recent decades, environmental issues have become an area of greatest concern due to changes in global climate conditions. The transportation sector is a major contributor to carbon dioxide emissions, accounting for more than 22.9% of total carbon dioxide emissions. At present, most vehicles run on gasoline/diesel as fuel which is unsustainable and unviable as fossil fuels produce carbon emissions and fuel costs are rising. To address these issues, electric vehicles (EVs) offer an attractive solution as alternative to internal combustion engine vehicles that use electricity as an energy source. It is logical to use renewable energy to charge vehicles, which makes renewable energy an end-to-end clean energy source. In electric vehicles, energy conversion plays an important role. In the energy conversion process, alternating current (AC) can be converted to direct current (DC), or direct current can be converted to alternating current. In EV fast charging applications, DC-to-DC conversion is used, which requires DC-to-DC converters. In this paper, a detailed evaluation of the Buck-Boost and Single-Ended Primary Inductance Converters (SEPIC) with PV as input is analyzed for EV charging applications to make it end-to-end clean energy. For this purpose, a 5-by-5 PV system with a Buck-Boost, SEPIC converters with particle swarm optimization technique is considered, which is simulated in a MATLAB/SIMULINK environment. The simulation results showed that the ripples in output are minimal in SEPIC which supports the smooth and efficient charging of EV battery.
11
Sabry, Ahmad H., Wan Zuha Wan Hasan, Mohd Zainal, Mohd Amran e Suhaidi B. Shafie. "DC Loads Matching Technique as an Alternative to AC Inverter in Residential Solar System Application Evaluation and Comparison". Applied Mechanics and Materials 785 (agosto 2015): 225–30. http://dx.doi.org/10.4028/www.scientific.net/amm.785.225.
Abstract (sommario):
since PV inverter cost and performance in residential Solar System Application is a controversial subject, it always needs to be researched to encounter the challenges of cost competitions especially with environmentally polluted fossil fuel energy expense. This research proposes a fundamentally novel solutions for utilizing the unavoidable solar system losses by the hypothesis of dispensing the power converters in domestic application of home solar system. This hypotheses based on matching methods between the energy source, the Battery bank, and the load, home appliances. Since the energy source is a direct current DC supply, this matching process would be via evaluating of the normal alternative current AC appliances and compatibility range to be switched on DC supply, the operation of the appliances evaluated individually with DC supply either by direct coupling or with simple modification, the analysis of the data have been accumulated in terms of efficiency. Individually, appliances were classified according to different aspects in such a way that shows its compatibility range with the DC power supply. A comparison results for each classified appliances have been done for both operation conditions AC and DC. The efficiency of a relatively good quality Inverter would be referred to see what gain would be obtained from switching to DC supply-load matching when eliminating of AC Inverter from the system. A sequence of processes have been carried out on home appliances individually in terms of its electrical and electronic composition towards best system performance and reasonable cost. MATLAB Simulink has been used as a simulation program. The results shows; great utilization of the home solar system losses, cost and faults probability reduction, high efficiency, and more reliable system.
12
Isaiev, V. V., e О. М. Velychko. "RESEARCH OF THE STATE PRIMARY STANDARD OF UNIT OF ALTERNATING CURRENT". Key title Zbìrnik naukovih pracʹ Odesʹkoï deržavnoï akademìï tehnìčnogo regulûvannâ ta âkostì -, n. 2(17) (2020): 14–22. http://dx.doi.org/10.32684/2412-5288-2020-2-17-14-22.
Abstract (sommario):
The article is devoted to the results of the research in order to solve the problem of metrological support of production and operation of thermoelectric power converters, precision meters and AC power sources in the branches of the national economy. The optimal solution to the problem of metrological support is to create a national standard unit of alternating current. The article conducts theoretical research, comparison with foreign analogues and analysis of methods for measuring and reproducing the strength of alternating current. The analysis of the precision means intended for measurement, reproduction and comparison of force and voltage of alternating current is carried out. Theoretical bases of creation of a high-precision standard of unit of alternating current are outlined. To build a national standard, the method of comparing the AC current with the equivalent DC current using a precision thermoelectric converter and shunts was chosen. The composition and requirements to the operating conditions of the national standard are determined. Since the storage and reproduction of a unit of alternating current must be realized by comparison with the equivalent direct current, the main source of uncertainty of measurements of this unit is a combination of uncertainties of measurements of thermoelectric comparator Fluke 792A, precision shunts A40, which are part of the standard, output voltage meters measure the electrical resistance to direct current and the output signal of the thermocomparator. According to the results of research work, for the first time in Ukraine the national standard of an alternating current unit was put into operation.
13
Dannier, Adolfo, Gianluca Brando e Francesca Ruggiero. "The Piezoelectric Phenomenon in Energy Harvesting Scenarios: A Theoretical Study of Viable Applications in Unbalanced Rotor Systems". Energies 12, n. 4 (21 febbraio 2019): 708. http://dx.doi.org/10.3390/en12040708.
Abstract (sommario):
The present paper deals with the promising energy harvesting applications of a composite piezoelectric metal support that is properly designed for the rotor of a mechanical system. The aim is to determine whether the vibrational power coming from the static residual imbalance, which is generally considered to be an undesired and useless side-effect of the rotation, can be converted into electric power and then stored to be used in other applications. The analysis, starting from the Jeffcott rotor model and the piezoelectric constitutive equations, has been carried out by developing an approximated linear model of a piezoelectric support, in order to theoretically evaluate the performance and the feasibility of the proposed system. The accuracy of the exploited analytical model has been validated for both static and dynamic operations by 3D Ansys® Mechanical APDL. Finally, a MatLab®/Simulink® model has been built to simulate the electric behavior of the piezoelectric material, and to estimate the power that it is possible to extract via an alternative/direct current converter (AC/DC converter). The numerical results achieved confirm the effectiveness of the proposed energy-harvesting system.
14
Oni, Oluwafemi Emmanuel, Andrew G. Swanson e Rudiren Pillay Carpanen. "Impact of LCC–HVDC multiterminal on generator rotor angle stability". International Journal of Electrical and Computer Engineering (IJECE) 10, n. 1 (1 febbraio 2020): 22. http://dx.doi.org/10.11591/ijece.v10i1.pp22-34.
Abstract (sommario):
<span>Multiterminal High Voltage Direct Current (HVDC) transmission utilizing Line Commutated Converter (LCC-HVDC) technology is on the increase in interconnecting a remote generating station to any urban centre via long distance DC lines. This Multiterminal-HVDC (MTDC) system offers a reduced right of way benefits, reduction in transmission losses, as well as robust power controllability with enhanced stability margin. However, utilizing the MTDC system in an AC network bring about a new area of associated fault analysis as well as the effect on the entire AC system during a transient fault condition. This paper analyses the fault current contribution of an MTDC system during transient fault to the rotor angle of a synchronous generator. The results show a high rotor angle swing during a transient fault and the effectiveness of fast power system stabilizer connected to the generator automatic voltage regulator in damping the system oscillations. The MTDC link improved the system performance by providing an alternative path of power transfer and quick system recovery during transient fault thus increasing the rate at which the system oscillations were damped out. This shows great improvement compared to when power was being transmitted via AC lines.</span>
15
Montilla-DJesus, Miguel, Édinson Franco-Mejía, Edwin Rivas Trujillo, José Luis Rodriguez-Amenedo e Santiago Arnaltes. "Coordinated Control System between Grid–VSC and a DC Microgrid with Hybrid Energy Storage System". Electronics 10, n. 21 (4 novembre 2021): 2699. http://dx.doi.org/10.3390/electronics10212699.
Abstract (sommario):
Direct current microgrids (DCMGs) are currently presented as an alternative solution for small systems that feed sensitive electrical loads into DC. According to the scientific literature, DCMG maintains good voltage regulation. However, when the system is in islanded mode, very pronounced voltage variations are presented, compromising the system’s ability to achieve reliable and stable energy management. Therefore, the authors propose a solution, connecting the electrical network through a grid-tied voltage source converter (GVSC) in order to reduce voltage variations. A coordinated control strategy between the DCMG and GVSC is proposed to regulate the DC voltage and find a stable power flow between the various active elements, which feed the load. The results show that the control strategy between the GVSC and DCMG, when tested under different disturbances, improves the performance of the system, making it more reliable and stable. Furthermore, the GVSC supports the AC voltage at the point of common coupling (PCC) without reducing the operating capacity of the DCMG and without exceeding even its most restrictive limit. All simulations were carried out in MATLAB 2020.
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Fang, Liew Hui, e Rosemizi bin Abd Rahim. "Design of Savonius model wind turbine for power catchment". International Journal of Electrical and Computer Engineering (IJECE) 12, n. 3 (1 giugno 2022): 2285. http://dx.doi.org/10.11591/ijece.v12i3.pp2285-2299.
Abstract (sommario):
In this study, the fossil fuel usage by-product is carbon dioxide, which is known as the primary cause in global warming. Alternatively, wind energy is a clean alternative energy source compared the fuel consumption can cause smoke pollution. The goal of the work is to develop a pollution controller device model Savonius wind turbine to represent the characterized actual speed wind turbine concepts into convert kinetic energy into electric energy from campus and monitoring all output data display on the cloud. The wind speed operation is enabled through the use of ESP8266 as internet of things (IoT) platform and the alternating current (AC) direct current (DC) harvesting circuit into improve stability of the wind energy performance. Secondly, a magnet coil synchronous generator is used, which is a grid coupled through a diode rectifier and voltage source converter. The parameters that have been measured using wireless fidelity (Wi-Fi) module ESP8266 are considering wind speed, current, voltage and power. The wind speed with 7.8 MPH can produce a maximum output voltage and output current of 1.104 V and 4.321 μA, respectively. Blynk applications functional as role present performance monitoring kit wind turbine analysis with more precise and efficient in anywhere and anytime.
17
Ammous, Anis, Abdulrahman Alahdal e Kaiçar Ammous. "Energy Efficiency of LVDC Supplies Including PV Sources". International Journal of Mathematics and Computers in Simulation 15 (6 aprile 2021): 46–53. http://dx.doi.org/10.46300/9102.2021.15.9.
Abstract (sommario):
The Low Voltage Direct Current (LVDC) system concept has been growing in the recent times due to its characteristics and advantages like renewable energy source compatibility, more straightforward integration with storage utilities through power electronic converters and distributed loads. This paper presents the energy efficiency performances of a proposed LVDC supply concept and others classical PV chains architectures. A PV source was considered in the studied nanogrids. The notion of Relative Saved Energy (RSE) was introduced to compare the studied PV systems energy performances. The obtained results revealed that the employment of the LVDC chain supply concept is very interesting and the use of DC loads as an alternative to AC loads, when a PV power is generated locally, is more efficient. The installed PV power source in the building should be well sized regarding to the consumed power in order to register a high system RSE.
18
Saadaoui, Khalil, Kaoutar Senhaji Rhazi, Youssef Mejdoub e Abderraouf Aboudou. "Modelling and simulation for energy management of a hybrid microgrid with droop controller". International Journal of Electrical and Computer Engineering (IJECE) 13, n. 3 (1 giugno 2023): 2440. http://dx.doi.org/10.11591/ijece.v13i3.pp2440-2448.
Abstract (sommario):
<span lang="EN-US">The most efficient and connected alternative for increasing the use of local renewable energy sources is a hybrid microgrid, these systems face additional challenges due to the integration of power electronics, energy storage technologies and traditional power plants. The hybrid <a name="_Hlk120713679"></a>alternating current-direct current (AC-DC) microgrid that is the subject of this research uses a primary-droop control system to regulate state variables and auxiliary services, thus, it is composed of batteries, solar panels and a miniature wind turbine (PDC) and controls how each energy source in a microgrid contributes to the final product. To achieve the given objectives, this paper will create appropriate models for each part of the microgrid design and define, among them, the energy storage batteries and power electronic converters required for each level of each of these systems. Finally, the dynamic nature of the system will be critically evaluated and characterized, to distribute the load and reduce imbalances, modify the primary drop of the resulting microgrid using MATLAB simulation.</span>
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Perdiansyah, Farhan, Eka Tiara Nur Fitriana, Nur Aziema, Permata Putri Maharani, Fitri Khoerunnisa e Nanang Winarno. "The Efficient Implementation of Hybrid Power Plants in Indonesia". Indonesian Journal of Multidiciplinary Research 1, n. 1 (20 aprile 2021): 151–58. http://dx.doi.org/10.17509/ijomr.v1i1.33772.
Abstract (sommario):
The energy crisis is a serious issue that all countries around the world are dealing with, particularly the energy sources used to generate electricity. There are numerous alternative energy sources available in nature, such as solar energy, wind energy, and so on. Wind and solar energy as hybrid energy sources are thought to be promising in electric generation technology. Hybrid Power Plants can also be used to address the issue of limited electrical energy supply in Indonesia's remote areas. The purpose of this study is to describe the effectiveness of the hybrid power plants implementation in Indonesia. The study was conducted using the narrative literature review method. It can be inferred that the purpose of developing this hybrid technology, among others, is to obtain more efficient electrical energy generation by combining the advantages of two or more types of power generation systems that work in an integrated manner as a compact system. The produced electric energy can be stored in the battery. In terms of use, the produced direct current (DC) is converted into alternating current (AC) using the inverter system prior to distribution to consumers. Therefore, this hybrid power plant is suitable to be implemented in Indonesia.
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Perdiansyah, Farhan, Eka Tiara Nur Fitriana, Nur Aziema, Permata Putri Maharani, Fitri Khoerunnisa e Nanang Winarno. "The Efficient Implementation of Hybrid Power Plants in Indonesia". ASEAN Journal of Science and Engineering 1, n. 3 (26 agosto 2021): 213–20. http://dx.doi.org/10.17509/ajse.v1i3.34226.
Abstract (sommario):
The energy crisis is a serious issue that all countries around the world are dealing with, particularly the energy sources used to generate electricity. There are numerous alternative energy sources available in nature, such as solar energy, wind energy, and so on. Wind and solar energy as hybrid energy sources are thought to be promising in electric generation technology. Hybrid Power Plants can also be used to address the issue of limited electrical energy supply in Indonesia's remote areas. The purpose of this study is to describe the effectiveness of the hybrid power plants implementation in Indonesia. The study was conducted using the narrative literature review method. It can be inferred that the purpose of developing this hybrid technology, among others, is to obtain more efficient electrical energy generation by combining the advantages of two or more types of power generation systems that work in an integrated manner as a compact system. The produced electric energy can be stored in the battery. In terms of use, the produced direct current (DC) is converted into alternating current (AC) using the inverter system prior to distribution to consumers. Therefore, this hybrid power plant is suitable to be implemented in Indonesia.
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Pratomo, Leonardus Heru, Agutinus Fidelis Wibisono e Slamet Riyadi. "Design and Implementation of Double Loop Control Strategy in TPFW Voltage and Current Regulated Inverter for Photovoltaic Application". Journal of Robotics and Control (JRC) 3, n. 2 (5 febbraio 2022): 196–204. http://dx.doi.org/10.18196/jrc.v3i2.14365.
Abstract (sommario):
Increasing demands for renewable energy encourage the development of inverters as a solution for converting energy from direct photovoltaic current (DC) output to alternative current (AC) at a maximum output power. Several nation standard systems are three-phase four-wired (TPFW), which means that the TPFW inverter must be used. The issue arises because the TPFW inverter is operated through an open-loop system, which has the problem of preventing the inverter from adjusting the voltage and current as needed. Hence, the open-loop system must be converted to a closed-loop system which is usually used only single control. The single strategy control is not effective because this strategy cannot regulate voltage and current at the same time. It only controls either voltage or current. The output voltage or current is changed when the load value is changed. Due to its weaknesses, the study proposes a new double-control strategy method that utilizes a PI strategy (P) controller as a voltage controller and a proportional strategy control as a current controller. This strategy is tested and measured by using simulation, showing a THD value of 1.07%. Accordance to IEEE standards, the THD value is within the recommended limit. Therefore, the output voltage and current produced have a good signal with a low ripple and stability without fluctuation.
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Septiana, Adella Wulan, e Iman Setiono. "PENGATURAN PERGESERAN SUDUT FASA 120º SEBAGAI PEMBANGKIT GELOMBANG KOTAK PADA INVERTER TIGA FASA". Gema Teknologi 19, n. 1 (31 ottobre 2016): 18. http://dx.doi.org/10.14710/gt.v19i1.21958.
Abstract (sommario):
Adella Wulan Septiana, Iman Setiono in this paper explain that Three phase electricity is widely used in large and home industries. However, not all industries or electricity users can enjoy three-phase resources because the installation is quite expensive. So that the use of a single phase to three phase electric converter is needed. One alternative that can be done is by making an inverter. The inverter is a hardware device that functions to convert direct current (DC) voltage into alternating current (AC) voltage. From the 220 VAC voltage enter the step up transformer then to the rectifier circuit so that the voltage generated is 380V. Then IC 555 is used as a box wave generator with a frequency output of 322.7 Hz. Then the output goes into the IC 74175 flip-flop circuit as a phase shift that produces three outputs, where each output has a high and low value with a frequency of 53.8 Hz. Output from rectifier and 74175 is used as input for IGBT drivers. Keywords: three phase electricity, shift register, flip-flop 74175, inverter.ReferencesAfrizal, Mokhamad Asrul & Ainur Rofiq. Perencanaan dan Pembuatan Modul Inverter 3 Phase sebagai Suplai Motor Induksi pada Penngembangan Modul Praktikum Pengemudi Listrik. Proyek Akhir D3 Teknik Elektro Industri. Surabaya: Politeknik Negeri Surabaya Institut Teknologi Sepuluh November.Agus Cahya & Dedid Cahya. Rancang Bangun Inverter 3 Fasa untuk Pengaturan Kecepatan Motor Induksi. Proyek Akhir Teknik Elektronika. Surabaya: Politeknik Negeri Surabaya Institut Teknologi Sepuluh November.Agus Rusdiyanto & Bambang Susanto. Perancangan Inverter Sinusoida 1 Fasa dengan Aplikasi Pemrograman Rumus Parabola dan Segitiga sebagai Pembangkit Pulsa PWM. http://www.telimek.lipi.go.id/xdata/docs/BS18.pdf.Erfan, JC. 2016. Inverter 3 Fasa 220 Volt dengan Output Sinusoidal Frekuensi 50 Hz menggunakan Arduino dengan Teknik Direct Synthesis. Tugas Akhir S1 Teknik Elektro. Surakarta: Universitas Muhammadiyah Surakarta.
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Mathew, Derick, Athira P. Ashok e Bincy M. Mathew. "Modified Single Stage AC-AC Converter". International Journal of Power Electronics and Drive Systems (IJPEDS) 6, n. 1 (1 marzo 2015): 1. http://dx.doi.org/10.11591/ijpeds.v6.i1.pp1-9.
Abstract (sommario):
<p>The paper describes the single stage AC-AC converter. This converter is a good alternative to quasi direct back to back converter. This single stage converter is called Matrix Converter. Matrix converter is an array of controlled semiconductor switches that connects three phase source to the three phase load. This converter provides bidirectional power flow, sinusoidal input and output waveforms and they have no dc link storage elements. Simulation model and results presented showing Venturini control method of matrix converter.</p>
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Sivapriyan, R., e D. Elangovan. "Impedance-Source DC-to-AC/DC Converter". Electronics 8, n. 4 (16 aprile 2019): 438. http://dx.doi.org/10.3390/electronics8040438.
Abstract (sommario):
This article presents a novel impedance-source-based direct current (DC)-to-alternating current (AC)/DC converter (Z-Source DAD Converter). The Z-Source DAD converter converts the input DC voltage into AC or DC with buck or boost in the load voltage. This Z-Source DAD conversion circuit is a single-stage power conversion system. This converter circuit converts the input DC voltage into variable-magnitude output DC voltage or converts the DC voltage into a variable-magnitude output AC voltage. The higher voltage magnitude in boost mode can be controlled by controlling the shoot-through (ST) state timing of the converter. MATLAB-Simulink simulation and microcontroller-based hardware circuit results are presented to demonstrate power conversion with the buck and boost features of the Z-Source DAD converter for both types of output voltages. The simulation and experimental results show that the Z-Source DAD converter converts the given DC supply into AC or DC with buck or boost in the output load voltage.
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FIJALKOWSKI, BOGDAN T., e JAN W. KROSNICKI. "CONCEPTS OF ELECTRONICALLY-CONTROLLED ELECTROMECHANICAL/MECHANOELECTRICAL STEER-, AUTODRIVE- AND AUTOABSORBABLE WHEELS FOR ENVIRONMENTALLY-FRIENDLY TRI-MODE SUPERCARS". Journal of Circuits, Systems and Computers 04, n. 04 (dicembre 1994): 501–16. http://dx.doi.org/10.1142/s0218126694000296.
Abstract (sommario):
Concepts of the electronically-controlled electromechanical/mechanoelectrical Steer-, Autodrive- and Autoabsorbable Wheels (SA2W) with their brushless Alternating Current-to-Alternating Current (AC-AC), Alternating Current-to-Direct Current-Alternating Current (AC-DC-AC) and/or Direct Current-to-Alternating Current (DC-AC)/Alternating Current-to-Direct Current (AC-DC) macroelectronic converter commutator (macro-commutator) wheel-hub motors/generators with the Application Specific Integrated Matrixer (ASIM) macroelectronic converter commutators (ASIM macrocommutators) and Application Specific Integrated Circuit (ASIC) microelectronic Neuro-Fuzzy (NF) computer (processor) controllers (ASIC NF microcontrollers) for environmentally-friendly tri-mode supercars (advanced ultralight hybrids) have been conceived by the first author and designed by both authors with the Cracow University of Technology’s Automotive Mechatronics Research and Development (R&D) Team. These electromechanical/mechanoelectrical wheel-hub motors/generators, respectively, for instance, can be composed of the outer rotor with the Interior Permanent Magnet (IPM) poles and the inner stator that has the three-phase armature winding. The macroelectronic converter commutator establishes the AC-AC cycloconverter, AC-DC rectifier-DC-AC inverter and/or DC-AC inverter/AC-DC rectifier ASIM macrocommutator. The microelectronic NF computer (processor) controller establishes the ASIC microcomputer-based NF microcontroller. By adopting continuous semiconductor bipolar electrical valves in the high-power ASIM, it has been able to increase the commutation (switching) frequency and reduce harmonic losses of the electromechanical/mechanoelectrical wheel-hub motors/generators, respectively.
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Rajendra Kumar, R., e Vivekananda Ganji. "Transformation of AC to DC using Direct Sequence Spread Spectrum (DSSS) Technique for Electromagnetic Inference". International Innovative Research Journal of Engineering and Technology 6, n. 3 (30 marzo 2021): 12–21. http://dx.doi.org/10.32595/iirjet.org/v6i3.2021.144.
Abstract (sommario):
Before more functions of the circuit are integrated into several electromagnetic a single die or small integrated die or small integrated interference (EMI) people impacted by ac-dc converter kit, expanding. The dominant electromagnetic emission. In this paper Alternate Current (AC) - Direct Current (DC) converter source is delineated by gauging the ac-dc converter source of the nodes' power spectrum. The activity of the noise scanner is linked to a noise scanner, a crowded ac-dc converter single-chip prototype. The data revealed the converter's superior electromagnetic source of the emission is the switching node, not the output node. The technique of direct sequence spread spectrum to counteract the switching node toxins, the ac- dc converter should be used and its profitability is the temperature distribution and pragmatically validated. The Mathematical statement of the technique of direct sequence spread spectrum is proposed for the study of its pharmacokinetics in the significant decrease of EMI and optimal installation using the technique of direct sequence spread spectrum with 0.18-μm CMOSS, dead-time control is assembled and coding. The plotted reduction in the power spectrum. The optimum direct sequence spread spectrum technique installation and managerial staff of dead-time is the node at the 16 dB switch. The stock of the proposed declines in the EMI reduction. The IC-strip line approach improved the design by 12.6 dB on fundamental frequency switching.
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Shahin, Rasha Ghilman, e Hussein Diab Al-Majali. "Performance analysis of multi-level high voltage direct current converter". International Journal of Electrical and Computer Engineering (IJECE) 12, n. 2 (1 aprile 2022): 1368. http://dx.doi.org/10.11591/ijece.v12i2.pp1368-1376.
Abstract (sommario):
<p class="Abstract">The conventional three-phase alternating current (AC) to direct current (DC) converter can be modified using two isolated-gate bipolar transistor (IGBT) as by-pass switches connected to tapping points on the secondary side of the transformer. This scheme yields a reduction in both harmonic contents and reactive volt-ampere absorption. This modified converter possibly eliminates the need for an on-load tap-changer on the converter transformer. The modified AC/DC converter is fully analyzed and implemented under balanced conditions using MATLAB-Simulink. The expressions of the output DC voltage are derived for different cases. The supply current harmonic contents, the reactive power absorption and the power factor have been compared for three schemes; the conventional bridge, the modified bridge using one by-pass IGBT valve and the modified bridge with two by-pass IGBT valves. </p>
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Huo, Zhi Cheng, Guang Xu Ren, Jia Ying Gao e Guo Bao Ding. "Design of Inverter Based on the Soft-Switched of High Frequency Pulse DC Loop". Advanced Materials Research 834-836 (ottobre 2013): 1114–17. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.1114.
Abstract (sommario):
Design a DC/AC converter based on simplex single voltage source high frequency pulse DC loop technology, the output is 115V400Hz, 0.9KVA and the input is three phase alternating current. The forward part is DC/DC converter which provides pulse D.C. to the back part DC/AC converter. Implement soft-switch by changing the on-off state of switching tubes on the inversion arm path at the zero-voltage instant of the pulse direct current, no need of the auxiliary resonant net. The system takes three-state DPM current hysteresis control mode, gets good performance on output wave and efficiency.
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Ghazali, Mohd Shukri bin Mohd, Rahimi Bin Baharom, Khairul Safuan Bin Muhammad e Dylan Dah-Chuan Lu. "Computer simulation model of multi-input multi-output converter using single-phase matrix converter". International Journal of Power Electronics and Drive Systems (IJPEDS) 13, n. 2 (1 giugno 2022): 1047. http://dx.doi.org/10.11591/ijpeds.v13.i2.pp1047-1055.
Abstract (sommario):
This paper presents a multi-input, multi-output power converter system using a single-phase matrix converter (SPMC) circuit topology. In particular, this technology is of vital importance in floating production such as offshore oil and gas platforms where space is crucial, therefore requiring a reduction in equipment size and weight. The proposed circuit topology only employed a single circuit to perform energy conversion of direct current (DC) to alternating current (AC), DC to DC, AC to DC, and AC to AC operations, thus can reduce the power losses resulting in high power density. As a result, it can promise technological advancement and convergence, hence, support the manufacturing sector transition to industry 4.0, and in line with the United Nation’s sustainable development goals. The proposed converter model will be validated in terms of electrical circuit operations through the computer simulation (MATLAB/Simulink) software.
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Mohd Yusoff, Nor Azizah, Azziddin M. Razali, Kasrul Abdul Karim, Auzani Jidin e Tole Sutikno. "An Analysis of Virtual Flux Direct Power Control of Three-Phase AC-DC Converter". International Journal of Power Electronics and Drive Systems (IJPEDS) 9, n. 3 (1 settembre 2018): 947. http://dx.doi.org/10.11591/ijpeds.v9.i3.pp947-956.
Abstract (sommario):
<p>This paper presents an analysis of virtual-flux direct power control (VFDPC) technique for the three-phase pulse width modulation (PWM) ac-dc converter. The proposed VFDPC is developed by assuming the grid voltage and converter line filters quantities are related to a virtual three-phase ac motor. The controller works with less number of sensors by eliminating the voltage sensors used for measuring the three-phase grid voltage. The grid virtual flux which is proportional to the grid voltage will be estimated from the information of converter switching states, line current, and dc-link output voltage. Several analyses are performed in order to study the steady state and dynamic performance of the converter, particularly during the load and DC voltage output reference variations. The proportional integral (PI) controller at the outer voltage control loop of VFDPC is tuned properly and the entire PWM ac-dc converter system is simulated using MATLAB/Simulink to ensure the dc output voltage follow the desired output voltage under steady state and dynamic conditions. Ac-dc converter utilizing the proposed VFDPC is able to generate three-phase input current waveforms that are almost sinusoidal with low harmonics contents which is less than 5% and near unity power factor (<em>pf</em>) operation.</p>
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Kavitha, Pasumalaithevan, e Bhaskaran Umamaheswari. "R Dump Converter without DC Link Capacitor for an 8/6 SRM: Experimental Investigation". Scientific World Journal 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/393629.
Abstract (sommario):
The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.
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Kang, Jin-Wook, Ki-Woong Shin, Hoon Lee, Kyung-Min Kang, Jintae Kim e Chung-Yuen Won. "A Study on Stability Control of Grid Connected DC Distribution System Based on Second Order Generalized Integrator-Frequency Locked Loop (SOGI-FLL)". Applied Sciences 8, n. 8 (16 agosto 2018): 1387. http://dx.doi.org/10.3390/app8081387.
Abstract (sommario):
This paper studies a second order generalized integrator-frequency locked loop (SOGI-FLL) control scheme applicable for 3-phase alternating current/direct current (AC/DC) pulse width modulation (PWM) converters used in DC distribution systems. The 3-phase AC/DC PWM converter is the most important power conversion system of DC distribution, since it can boost 380 Vrms 3-phase line-to-line AC voltage to 700 Vdc DC output with various DC load devices and grid voltages. The direct-quadrature (d-q) transformation, positive sequence voltage extraction, proportional integral (PI) voltage/current control, and phase locked loop (PLL) are necessary to control the 3-phase AC/DC PWM converter. Besides, a digital filter, such as low pass filter and all pass filter, are essential in the conventional synchronous reference frame-phase locked loop (SRF-PLL) method to eliminate the low order harmonics of input. However, they limit the bandwidth of the controller, which directly affects the output voltage and load of 3-phase AC/DC PWM converter when sever voltage fluctuation, such as sag, swell, etc. occurred in the grid. On the other hand, the proposed control method using SOGI-FLL is able to do phase angle detection, positive sequence voltage extraction, and harmonic filtering without additional digital filters, so that more stable and fast transient control is achieved in the DC distribution system. To verify the improvement of the characteristics in the unbalanced voltage and frequency fluctuation of the grid, a simulation and experiment are implemented with 50 kW 3-phase AC/DC PWM converter used in DC distribution.
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Pesce, Cristián, Javier Riedemann, Rubén Peña, Iván Andrade, Werner Jara e Rodrigo Villalobos. "Decoupled Control for Double-T Dc-Dc MMC Topology for MT-HVdc/MVdc Grids". Applied Sciences 13, n. 6 (16 marzo 2023): 3778. http://dx.doi.org/10.3390/app13063778.
Abstract (sommario):
This paper proposes a decoupled control of a dc-dc modular multilevel converter (MMC) based on a double-T topology intended for multi-terminal high voltage direct current (MT-HVdc) transmission systems or emerging distribution systems operating in medium voltage direct current (MVdc). The aim of the proposed control strategy is to obtain an input current with reduced harmonic content and to eliminate the output ac common-mode voltage, which is not allowed in MT-HVdc systems. The control strategy consists of injecting two circulating ac currents and two dc currents that allow the energy balance between the arms of the converter and the general energy balance of the topology. The dc and ac currents are decoupled and allow control over load variations and reference changes in the dc-links. The proposed topology is mathematically modeled and the control method is then derived. Simulation results are presented to validate the proposed system.
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El-Shahat, Adel, e Sharaf Sumaiya. "DC-Microgrid System Design, Control, and Analysis". Electronics 8, n. 2 (24 gennaio 2019): 124. http://dx.doi.org/10.3390/electronics8020124.
Abstract (sommario):
Recently direct current (DC) microgrids have drawn more consideration because of the expanding use of direct current (DC) energy sources, energy storages, and loads in power systems. Design and analysis of a standalone solar photovoltaic (PV) system with DC microgrid has been proposed to supply power for both DC and alternating current (AC) loads. The proposed system comprises of a solar PV system with boost DC/DC converter, Incremental conductance (IncCond) maximum power point tracking (MPPT), bi-directional DC/DC converter (BDC), DC-AC inverter and batteries. The proposed bi-directional DC/DC converter (BDC) lessens the component losses and upsurges the efficiency of the complete system after many trials for its components’ selection. Additionally, the IncCond MPPT is replaced by Perturb & Observe (P&O) MPPT, and a particle swarm optimization (PSO) one. The three proposed techniques’ comparison shows the ranking of the best choice in terms of the achieved maximum power and fast—dynamic response. Furthermore, a stability analysis of the DC microgrid system is investigated with a boost converter and a bidirectional DC-DC converter with the Lyapunov function for the system has been proposed. The complete system is designed and executed in a MATLAB/SIMULINK environment and validated utilizing an OPAL real-time simulator.
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Vasilev, Bogdan, e Le Van Tung. "Research methods of V/F control for matrix converter use direct space vector modulation". International Journal of Electrical and Computer Engineering (IJECE) 9, n. 6 (1 dicembre 2019): 5115. http://dx.doi.org/10.11591/ijece.v9i6.pp5115-5124.
Abstract (sommario):
Matrix converter (MC) is direct AC to AC converter built on bidirectional switches with more outstanding advantages compared to the indirect AC - DC-AC converter such as power exchange in two directions, allowing regenerative braking performance amount returned grid. However, the modulation method for Matrix converter has the disadvantage of low voltage transmission ratio, current at the input and output current, the voltage of converter has many high-order harmonic components. The paper presents the technique of directly modulating the space vector which will improve the quality of matrix converter such as input and output currents with sine form, power factor input is nearly 1 and can be adjusted. Also, build V/F control method for matrix converter to control three-phase alternating current induction motors. Research results are tested by Matlab & Simulink software.
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Upendar, Jalla, Sangem Ravi Kumar, Sapavath Sreenu e Bogimi Sirisha. "Implementation and study of fuzzy based KY boost converter for electric vehicle charging". International Journal of Applied Power Engineering (IJAPE) 11, n. 1 (1 marzo 2022): 98. http://dx.doi.org/10.11591/ijape.v11.i1.pp98-108.
Abstract (sommario):
Elecetric vehicle batteries require direct current (DC) current for charging; hence the circuit alternating current (AC) is converted to DC by a battery charger. Battery charger mostly consists of a rectifier and DC-DC converter with a controller built in to serve as a protective circuit. A harmonic source load is a type of electric car charger. During the AC-DC change over method, harmonic current is introduced into the power system, affecting power quality. In this study, a charging station consisting of buck boost and a charging station consisting a KY Boost converter were simulated. To maintain output voltage of DC-DC converters constant controller is used, the controller is either PI or fuzzy logic controller. So, four models are developed and simulated which are buck-boost converter controlled by proportional-integral (PI)-controller, KY-boost converter controlled by proportional integral-controller, buck boost converter controller fuzzy logic controller and KY boost-converter controlled by fuzzy logic controller. The total harmonic distortion (THD) of the four models is compared.
37
Zheng, Ningkang, Xiangyang YanHuanruo, Huanruo Qi e Yilong Kang. "Study of A Bus Voltage Control Strategy for Two-Way AC/DC Current Converter in DC Microgrid". E3S Web of Conferences 185 (2020): 01061. http://dx.doi.org/10.1051/e3sconf/202018501061.
Abstract (sommario):
In an isolated DC microgrid consisting of photovoltaic cells, an energy storage unit and load, reasonable control of grid-connected two-way AC/DC converter can effectively realize coordinated power distribution and bus voltage stabilization of the microgrid. A mathematical model of grid-connected converter was established first in this paper, followed by a simulation analysis of the grid-connected converter under direct voltage control. In consideration of the fact that the ideal dynamic voltage response could not be realized by conventional control of the grid-connected converter, a seamless switching control strategy of inhibiting voltage fluctuation was proposed based on the voltage fluctuation analysis of the AC/DC converter, which improved the robust stability of the DC microgrid. The effectiveness and feasibility of the proposed control strategy were verified through the simulation results.
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Santos, Nelson, J. Fernando Silva e Vasco Soares. "Control of Single-Phase Electrolytic Capacitor-Less Isolated Converter for DC Low Voltage Residential Networks". Electronics 9, n. 9 (29 agosto 2020): 1401. http://dx.doi.org/10.3390/electronics9091401.
Abstract (sommario):
In recent years, there has been a desire to improve electricity generation and consumption, to reach sustainability. Technological solutions today allow a rational use of electricity with good overall performance. Traditionally, from production to distribution, electrical energy is AC-supported for compatibility reasons and easy voltage level transformation. However, nowadays most electric loads need DC power to work properly. A single high-efficiency central AC-DC power converter may be advantageous in eliminating several less efficient AC-DC embedded converters, distributed all over a residential area. This paper presents a new single-phase AC-DC converter using one active bridge (most isolated topologies are based on the dual active bridge concept) and a high-frequency isolation transformer with low-value non-electrolytic capacitors, together with its control system design. The converter can be introduced into future low-voltage DC microgrids for residential buildings, as an alternative to several embedded AC-DC converters. Non-linear control techniques (sliding mode control and the Lyapunov direct method) are employed to guarantee stability in the output DC low voltage with near unity power factor compensation in the AC grid. The designed converter and controllers were simulated using Matlab/Simulink and tested in a lab experimental prototype using digital signal processing (DSP) to evaluate system performance.
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Rehman, Bilawal, Atiq Ur Rehman, Waqar Ahmad Khan, Jan Muhammad e Syed Mudassir Hussain. "Estimation of multi-infeed HVDC inter converter direct current interaction in close electric proximity". Mehran University Research Journal of Engineering and Technology 42, n. 2 (28 marzo 2023): 10. http://dx.doi.org/10.22581/muet1982.2302.02.
Abstract (sommario):
This paper aims at investigating the direct current interaction between various converters of High Voltage Direct Current (HVDC) system, which lie in close electric proximity within the multi-infeed configuration. The interaction between converters in multi-infeed DC system are highly possible events which need to be evaluated in order to avoid the adverse operational results. The various indices such as multi-infeed interaction factor (MIIF) considering AC busbar voltages, local and concurrent commutation failures (CF) in converter stations under different AC disturbances, influence of AC system’s strength on fault recovery time (FRT), transient over-voltage (TOV) under permanent DC faults, voltage and power stability of multi-infeed DC system are comprehensively illustrated in literatures. However, there is lack of literature regarding the investigation of current interaction in multi-infeed DC system. Therefore, in this paper, a power flow approach is adopted to estimate the inter converter direct current interaction. An index, multi-infeed current interaction factor (MICIF) is proposed that can effectively depicts the interaction between converters. The MICIF index is verified through electromagnetic transient simulations of dual infeed HVDC system developed in PSCAD/EMTDC. The results show that MICIF index can accurately assess the interaction between different converter stations of HVDC system under steady and transient states.
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Piasecki, Szymon, Jaroslaw Zaleski, Marek Jasinski, Serafin Bachman e Marek Turzyński. "Analysis of AC/DC/DC Converter Modules for Direct Current Fast-Charging Applications". Energies 14, n. 19 (5 ottobre 2021): 6369. http://dx.doi.org/10.3390/en14196369.
Abstract (sommario):
The paper is a comprehensive laboratory comparison study of two galvanic isolated solution off-board battery chargers: (1) Si-based cost-effective case, and (2) SiC-bidirectional ready for vehicle to grid concept case. All circuits are modular, and in both cases the DC/DC converter can be replaced according to the end user requirements (the coupled transformer remains the same and is constructed based on 12xC100 cores to avoid additional choke). In the case of single active bridge, an active RCD snubber is proposed to protect against overvoltage above 1kV in the DC_2 circuit. The dual active bridge is equipped with soft-star modulation using a zero vector to reduce in-rush current in case of no-load operation, while the AC/DC grid connected converter remains bidirectional to assure the highest power quality at the point of common coupling. All tests were made with real second-used batteries, which improves environmental, economic and technical feasibility of such systems for prosumers. The total efficiency of both AC/DC/DC converters (>97% in SiC and >94% in Si versions) was investigated in the same laboratory conditions.
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Shkirmontov, A. P., e S. A. Bishenov. "Comparison parameters for carbon ferrochrome smelting in AC and DC furnaces". Izvestiya. Ferrous Metallurgy 63, n. 2 (29 aprile 2020): 163–65. http://dx.doi.org/10.17073/0368-0797-2020-2-163-165.
Abstract (sommario):
One of the interesting technical solutions is technology of ferroalloys smelting using direct current (DC). In DC ferroalloy furnaces, apparently, it is possible to eliminate such a parameter as power factor in furnace circuit after current converter. Many researchers assume that melting at direct current allows intensification of the process of charge melting, increases reduction of leading elements of ferroalloy and reduces specific consumption of electricity. In this paper, brief analysis of carbon ferrochromium smelting in alternating current (AC) and in direct current (DC) furnaces is made based on energotechnological criterion of ferroalloy electric furnace performance. It is shown that with comparable active capacity in bath, AC furnaces have higher energotechnological criteria (0.2185 – 0.2381), compared to DC furnaces (0.1109 – 0.1320), at current level of technology used for carbonaceous ferrochrome smelting. Thus, in AC furnaces, specific electric power consumption in ferrochrome smelting is lower than in DC furnaces by 20 – 28 %.
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Chen, Yongtao, Zhi Liu, Pengbo Wang e Fan Yang. "Characterization of electric field distribution in valve-side casing of 500 kV converter transformer considering AC and DC mixed voltage". Journal of Physics: Conference Series 2741, n. 1 (1 aprile 2024): 012062. http://dx.doi.org/10.1088/1742-6596/2741/1/012062.
Abstract (sommario):
Abstract The converter transformer, as one of the indispensable core devices in the ultra-high voltage direct current (UHVDC) transmission system, exhibits highly complex electric field distribution characteristics within the valve-side bushing. In-depth research into the electric field distribution characteristics and variation patterns of the valve-side bushing under both alternating current (AC) and direct current (DC) voltage conditions is crucial for ensuring the reliable operation of the transmission system. This study focuses on investigating the electric field distribution of the valve-side bushing under AC and DC voltage excitations. A full-scale finite element model of the valve-side bushing of the converter transformer is constructed using finite element simulation software for modeling and research purposes. The results indicate that the internal electric field distribution of the bushing is generally similar under both AC and DC voltage excitations. However, in the SF6-filled region, a steeper voltage drop is observed under DC excitation compared to AC. The space charges generated in the DC electric field due to field polarization have a significant impact on the distortion of the electric field on the inner and outermost layer electrode plates. These conclusions provide theoretical guidance for the insulation design of the valve-side bushing in converter transformers at the 500 kV voltage level and similar ratings.
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Halim, Levin, Frans Cevin Hutabarat, Alma Sucianti Adam e Lucky Icha Pratama Manafe. "Datasheet-Based Efficiency Comparison Analysis of Alternating Current (AC) And Direct Current (DC) Electrical Systems". Journal of World Science 2, n. 11 (30 novembre 2023): 1766–81. http://dx.doi.org/10.58344/jws.v2i11.471.
Abstract (sommario):
In today's electrical infrastructure, a significant portion continues to depend on the AC (alternating current) system, necessitating energy conversion from DC (direct current) to AC during power generation and vice versa when reaching consumers. Nonetheless, as renewable energy sources and DC-based electronic devices gain popularity, the DC electrical system presents an attractive alternative. This research compares the energy efficiency between AC and DC electrical systems in school buildings. Through literature review and energy analysis in school buildings, the study found that the DC electrical system is significantly more efficient, achieving an efficiency rate of 89%. In contrast, the AC system only reaches 84%. The implications of this research provide valuable insights for implementing more efficient and sustainable electrical systems in buildings in the future.
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Tyagi, Charu, e Shivam Sharma. "Review of Matrix Converter Modulation Topology (Venturini Method) and Its Application". International Journal of Advance Research and Innovation 2, n. 2 (2014): 119–22. http://dx.doi.org/10.51976/ijari.221417.
Abstract (sommario):
This paper presents an overview of the matrix converter and its modulation techniques with application. Matrix converter is one of the most interesting members of power converter family; provide direct AC-AC conversion. A matrix converter is an ac-ac power frequency converter that received extension research attention due to its single stage power conversion technique, which is an alternate to ac-dc-ac converter.MC (matrix converter) is capable to convert energy from an ac source to ac load without the need of bulky and life- time limited energy storage elements. Here the purpose of most of these modulation methods is to generate sinusoidal current on the input and output sides. These methods are compared on the basis of theoretical complexities and performance.
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Ouyang, Jinxin, Yujie Chen, Xinyu Pan e Yanbo Diao. "An Improved Suppression Method of AC Transient Overvoltage for Line Commuted Converter Based High Voltage Direct Current Considering AC-DC System Coupling". Electronics 13, n. 10 (9 maggio 2024): 1844. http://dx.doi.org/10.3390/electronics13101844.
Abstract (sommario):
Commutation failures in line commuted converter-based high voltage direct current (LCC-HVDC) transmission systems leads to an increase in the converter bus voltage of the rectifier station, thus resulting in AC transient overvoltage in the sending-end grid. The transient overvoltage could lead to the disconnection of renewable energy generation and threaten the stable operation of the sending-end grid. However, the influences of the coupling between AC and DC systems caused by the interaction between the active and reactive power of the sending-end grid, the AC bus voltage of the rectifier station, and the DC current are ignored. The AC transient overvoltage cannot be accurately suppressed. Therefore, in this study, the transient voltage characteristics of the rectifier station under a commutation failure of the inverter station are analyzed. The influence of LCC-HVDC control on the AC bus voltage of a rectifier station through the active and reactive power of the rectifier station is analyzed. A dynamic model of the AC bus voltage of a rectifier station under an AC-DC system coupling is established. The calculation method of the command value of the DC current of the rectifier station is proposed by a predictive control model, and an improved suppression method for AC transient overvoltage is proposed. The case studies show that the accuracy and effectiveness of the suppression of AC transient overvoltage are improved by considering the coupling between AC and DC systems.
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Ayiad, Motaz, Helder Leite e Hugo Martins. "State Estimation for Hybrid VSC Based HVDC/AC Transmission Networks". Energies 13, n. 18 (20 settembre 2020): 4932. http://dx.doi.org/10.3390/en13184932.
Abstract (sommario):
As the integration of High Voltage Direct Current (HVDC) systems on modern power networks continues to expand, challenges have appeared in different fields of the network architecture. In the Supervisory, Control and Data Acquisition (SCADA) field, software and toolboxes are expected to be modified to meet the new network characteristics. Therefore, this paper presents a unified Weighted Least Squares (WLS) state estimation algorithm suitable for hybrid HVDC/AC transmission systems, based on Voltage Source Converter (VSC). The mathematical formulas of the unified approach are derived for modelling the AC, DC and converter coupling components. The method couples the AC and DC sides of the converter through power and voltage constraints and measurement functions. Two hybrid power system test cases have been studied to validate this work, a 4-AC/4-DC/4-AC network and Cigre B4 DC test case network. Furthermore, comparison between the fully decentralized state estimation and the unified method is provided, which indicated an accuracy improvement and error reduction.
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Abdollahi, Rohollah. "Harmonic reduction using a novel multipulse AC-DC converter". World Journal of Engineering 15, n. 4 (6 agosto 2018): 520–30. http://dx.doi.org/10.1108/wje-11-2017-0353.
Abstract (sommario):
Purpose For direct torque controlled induction motor drives, an effective solution to eliminate harmonics is the use of multipulse alternating current (AC)-direct current (DC) converters. Many researchers have used different configurations based on 24- and 30-pulse rectifications for improved power quality. However, the total harmonic distortion (THD) of AC mains current with these topology is more than 4 per cent when operating at a light load. For mitigating the THD problems observed in the input currents, Abdollahi propose 40-, 72- and 88-pulse AC-DC converters, while the power quality enhancement was the main concern. It is known that by increasing the number of pulses further results in reduction in current harmonics, but this is accompanied by an increase in cost and complexity. In this context, the purpose of this paper is to design a new delta/hexagon transformer based 36-pulse AC-DC converter for harmonic reduction without increasing the cost and complexity. Design/methodology/approach The proposed converter consists of two paralleled 18-pulse AC-DC converters involving a nine-phase shifted uncontrolled diode bridges with an interphase transformer circuit. Findings In this paper, the proposed scheme is simulated by matrix laboratory (MATLAB)/SIMULINK considering different loading scenarios. The simulation results show that the proposed scheme improves the power quality indices and satisfies the The Institute of Electrical and Electronics Engineers (IEEE)-519 requirements at the point of common coupling. Also, a laboratory prototype is implemented using the proposed design, and the experimental results confirm the simulation results under different loading conditions. Originality/value The proposed solution is a tradeoff among the pulse number, the transformer platform, the complexity of the scheme and the cost. The proposed scheme has an optimized configuration in this regard.
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Razali, Azziddin M., Nor Azizah Yusoff, Kasrul Abdul Karim, Auzani Jidin e Tole Sutikno. "A new switching look-up table for direct power control of grid connected 3L-NPC PWM rectifier". International Journal of Power Electronics and Drive Systems (IJPEDS) 12, n. 3 (1 settembre 2021): 1413. http://dx.doi.org/10.11591/ijpeds.v12.i3.pp1413-1421.
Abstract (sommario):
This paper presents a comprehensive and systematic approach in developing a new switching look-up table for direct power control (DPC) strategy applied to the three-phase grid connected three-level neutral-point clamped (3L-NPC) pulse width modulated (PWM) rectifier. The term of PWM rectifier used in this paper is also known as AC-DC converter. The approach provides detailed information regarding the effects of each multilevel converter space vector to the distribution of input active and reactive power in the converter system. Thus, the most optimal converter space vectors are able to be selected by the switching look-up table, allowing smooth control of the active and reactive powers for each sector. In addition, the proposed DPC utilizes an NPC capacitor balanced strategy to enhance the performance of front-end AC-DC converter during load and supply voltage disturbances. The steady state as well as the dynamic performances of the proposed DPC are presented and analyzed by using MATLAB/Simulink software. The results show that the AC-DC converter utilizing the new look-up table is able to produce almost sinusoidal line currents with lower current total harmonic distortion, unity power factor operation, adjustable DC-link output voltage and good dynamic response during load disturbance.
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Wang, Ting, Kun Chen, Long’en Zhang, Xingyang Hu, Hengxuan Li e Pangqi Ye. "Research on Fault Identification of Hybrid Multi-Feed High-Voltage Direct Current System Based on Line Commutated Converter and Voltage Source Converter". Energies 17, n. 9 (4 maggio 2024): 2215. http://dx.doi.org/10.3390/en17092215.
Abstract (sommario):
With the rapid development of voltage source converter (VSC) and line commutated converter (LCC) technology and the relative concentration of power and load, the inverter station of the flexible DC system is fed into the same AC bus with the conventional DC rectifier station, and the high-voltage direct current (HVDC) parallel hybrid feed system is formed in structure. As the electrical distance between the converter stations is very close, when a fault occurs in the near area, the current on the AC wiring on the VSC side will fluctuate greatly, resulting in the misoperation of the AC wiring protection. For this reason, this paper proposes a fault identification method based on VSC/LCC hybrid multi-fed HVDC system, which discriminates the fault and outputs the protection signal according to the protection criterion, and logically judges the combination of the output protection signal to identify the fault type. The simulation results show that the method can identify all kinds of faults of hybrid multi-feed DC system and solve the problem of protection misoperation of the hybrid multi-feed DC system.
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Hasan, Nazmul, e Tarak Saha. "single-phase bidirectional AC-AC converter with H-bridge energy buffer for wireless power transfer applications". International Journal of Power Electronics and Drive Systems (IJPEDS) 13, n. 1 (1 marzo 2022): 191. http://dx.doi.org/10.11591/ijpeds.v13.i1.pp191-199.
Abstract (sommario):
This paper introduces a single-phase bidirectional AC-AC Matrix type converter for wireless power transfer (WPT) applications. The proposed converter converts mains 50 Hz alternating current (AC) directly to high frequency 85 kHz AC without an intermediate direct current (DC) conversion stage. A minimum cost realization of only two bidirectional AC switches comprised each of two semiconductor device and one gate drive signal is employed. The converter operation modes are quantum energy injection and circulating self-oscillation. Elimination of the DC link introduces a sag in the power transfer during the zero crossing of input AC mains, which is well documented in literature. A novel H-bridge buffer structure is introduced which eliminates the power sag by storing energy during mains peak and delivering energy during the zero-crossing period. The converter operates with inherent zero current switching, thus achieving a low switching loss and electro-magnetic interference. The control feature ensures that the converter can be used for both static and dynamic wireless charging applications. The bidirectional power transfer capability ensures that the system can operate in both grid to vehicle (G2V) and vehicle to grid (V2G) power transfer modes. The proposed converter design is analyzed analytically and verified through thorough simulation study.