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Keywords = instantaneous power equation

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18 pages, 9706 KiB  
Article
Dynamics Study of Hybrid Support Flywheel Energy Storage System with Damping Ring Device
by Mingming Hu, Kun Liu, Jingbo Wei, Eryong Hou, Duhe Liu and Xi Zhao
Actuators 2024, 13(12), 532; https://doi.org/10.3390/act13120532 - 23 Dec 2024
Viewed by 1124
Abstract
The flywheel energy storage system (FESS) of a mechanical bearing is utilized in electric vehicles, railways, power grid frequency modulation, due to its high instantaneous power and fast response. However, the lifetime of FESS is limited because of significant frictional losses in mechanical [...] Read more.
The flywheel energy storage system (FESS) of a mechanical bearing is utilized in electric vehicles, railways, power grid frequency modulation, due to its high instantaneous power and fast response. However, the lifetime of FESS is limited because of significant frictional losses in mechanical bearings and challenges associated with passing the critical speed. To suppress the unbalanced response of FESS at critical speed, a damping ring (DR) device is designed for a hybrid supported FESS with mechanical bearing and axial active magnetic bearing (AMB). Initially, the dynamic model of the FESS with DR is established using Lagrange’s equation. Moreover, the dynamic parameters of the DR are obtained by experimental measurements using the method of free vibration attenuation. Finally, the influence of the DR device on the critical speed and unbalanced response of FESS is analyzed. The results show that the designed DR device can effectively reduce the critical speed of FESS, and increase the first and second mode damping ratio. The critical speed is reduced from 13,860 rpm to 5280 rpm. Compared with FESS of the mechanical bearing, the unbalanced response amplitude of the FESS with DR is reduced by more than 87.8%, offering promising technical support for the design of active and passive control systems in FESS. Full article
(This article belongs to the Special Issue Actuator Technology for Active Noise and Vibration Control)
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19 pages, 6814 KiB  
Article
Disturbance-Suppression Method of Direct-Driven PMSG-Based Wind Power System in Microgrids
by Xiuqi Xu, Liancheng Xiu, Jingxuan He and Rongxin Gong
Processes 2023, 11(7), 2189; https://doi.org/10.3390/pr11072189 - 21 Jul 2023
Cited by 2 | Viewed by 1210
Abstract
In order to solve the current fluctuation problem in microgrids, a suppression method called the Direct-driven Permanent Magnet Synchronous Generator (DPMSG)-based Wind Power System (WPS) based on an adaptive enhanced moving average filter algorithm is proposed. Firstly, the mathematical model of the WPS [...] Read more.
In order to solve the current fluctuation problem in microgrids, a suppression method called the Direct-driven Permanent Magnet Synchronous Generator (DPMSG)-based Wind Power System (WPS) based on an adaptive enhanced moving average filter algorithm is proposed. Firstly, the mathematical model of the WPS is established. On this basis, the suppression method under unbalanced conditions is derived by the instantaneous power equation to ensure the stable operation of the microgrid. In order to improve the dynamic compensation capability of the DPMSG-based WPS, an enhanced moving average filtering algorithm with frequency adaptability is proposed. The positive and negative sequence components are obtained in the dq frame by this filtering algorithm. Subsequently, the angular frequency of the microgrid is obtained according to the changing phase, which realizes the high-performance control of the WPS and avoids the complicated parameter adjustment of traditional methods. The correctness of this method is verified by the simulation results. The DPMSG-based WPS with the proposed method can improve the stability of the microgrid. Full article
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20 pages, 527 KiB  
Article
A Self-Charging Concentration Cell: Theory
by D.P. Sheehan
Batteries 2023, 9(7), 372; https://doi.org/10.3390/batteries9070372 - 10 Jul 2023
Cited by 4 | Viewed by 2287
Abstract
Batteries are a key resource in the quest for sustainable energy. Here, the theoretical basis is presented for a new type of electrochemical concentration cell that might contribute to this enterprise. The cell, which has been successfully demonstrated in the laboratory, incorporates a [...] Read more.
Batteries are a key resource in the quest for sustainable energy. Here, the theoretical basis is presented for a new type of electrochemical concentration cell that might contribute to this enterprise. The cell, which has been successfully demonstrated in the laboratory, incorporates a chemically asymmetric membrane to drive anisotropic diffusion between two solution chambers; the resulting concentration difference powers the cell. In this study, the membrane’s operation is validated via three theoretical approaches: (i) traditional equilibrium thermodynamics; (ii) balancing drift and diffusion current densities; and (iii) the time-independent diffusion equation. The physical criteria for its operation are developed and its dimensionless variables identified. The cell’s maximum instantaneous power density might exceed 107 W/m3. Its self-charging capability should confer multiple advantages over traditional concentration cells (as well as over some voltaics), including improved thermodynamic efficiency, economy, and compactness. Commonalities with other electrochemical systems (e.g., liquid chromatography, metal corrosion, and solid state diodes) are discussed, and a physical instantiation of the cell is reviewed. Recent numerical simulations corroborate its essential processes. Full article
(This article belongs to the Section Battery Mechanisms and Fundamental Electrochemistry Aspects)
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20 pages, 2485 KiB  
Article
A Reputation-Based Collaborative User Recruitment Algorithm in Edge-Aided Mobile Crowdsensing
by Yang Liu, Yong Li, Wei Cheng, Weiguang Wang and Junhua Yang
Appl. Sci. 2023, 13(10), 6040; https://doi.org/10.3390/app13106040 - 14 May 2023
Cited by 6 | Viewed by 2037
Abstract
Mobile CrowdSensing (MCS) has become a convenient method for many Internet of Things (IoT) applications in urban scenarios due to the full utilization of the mobility of people and the powerful capabilities of their intelligent devices. Nowadays, edge computing has been introduced into [...] Read more.
Mobile CrowdSensing (MCS) has become a convenient method for many Internet of Things (IoT) applications in urban scenarios due to the full utilization of the mobility of people and the powerful capabilities of their intelligent devices. Nowadays, edge computing has been introduced into MCS to reduce the time delays and computational complexity in cloud platforms. To improve task completion and coverage rates, how to design a reasonable user recruitment algorithm to find suitable users and take full advantage of edge nodes has raised huge challenges for Mobile CrowdSensing. In this study, we propose a Reputation-based Collaborative User Recruitment algorithm (RCUR) under a certain budget in an edge-aided Mobile CrowdSensing system. We first introduce edge computing into MCS and build an edge-aided MCS system in urban scenarios. Moreover, we analyze the influence of user reputation on user recruitment. Then we establish a user reputation module to deduce the user reputation equation by combining the user’s past reputation score with an instantaneous reputation score. Finally, we utilize the sensing ability of edge nodes and design a collaborative sensing method. We use the greedy method to help choose the appropriate users for the tasks. Simulation results compared with the other three algorithms prove that our RCUR approach can significantly achieve better performance in task completion rate and task coverage rate. Full article
(This article belongs to the Special Issue New Insights into Pervasive and Mobile Computing)
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16 pages, 7086 KiB  
Article
Research on Wake Field Characteristics and Support Structure Interference of Horizontal Axis Tidal Stream Turbine
by Jiayan Zhou, Huijuan Guo, Yuan Zheng, Zhi Zhang, Cong Yuan and Bin Liu
Energies 2023, 16(9), 3891; https://doi.org/10.3390/en16093891 - 4 May 2023
Cited by 2 | Viewed by 1670
Abstract
The harnessing and utilization of tidal current energy have emerged as prominent topics in scientific inquiry, due to their vast untapped resource potential, leading to numerous investigations into the efficacy of hydrokinetic turbines under various operational conditions. This paper delineates the wake field [...] Read more.
The harnessing and utilization of tidal current energy have emerged as prominent topics in scientific inquiry, due to their vast untapped resource potential, leading to numerous investigations into the efficacy of hydrokinetic turbines under various operational conditions. This paper delineates the wake field characteristics and performance of horizontal axis tidal stream turbines under the influence of support structures, using a comprehensively blade-resolved computational fluid dynamics (CFDs) model that employs Reynolds-averaged Navier–Stokes (RANS) equations in combination with the RNG k-ε turbulence model. To achieve this, the study utilized experimental tank tests and numerical simulations to investigate the distribution characteristics and recuperative principles of the turbine’s wake field. The velocity distribution and energy augmentation coefficient of the wake field showed strong agreement with the experimental results. To further assess the effect of support structures on the flow field downstream of the unit and its performance, the hydrodynamic attributes of the turbine wake field were analyzed with and without support structures. The interference elicited by the support structure modified the velocity distribution of the near-wake flow field, resulting in a 4.41% decrease in the turbine’s power coefficient (Cp), significantly impacting the turbine’s instantaneous performance. Full article
(This article belongs to the Special Issue Recent Advances in Wind Farms)
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10 pages, 590 KiB  
Article
Understanding the Spread of Fake News: An Approach from the Perspective of Young People
by Alejandro Valencia-Arias, Diana María Arango-Botero, Sebastián Cardona-Acevedo, Sharon Soledad Paredes Delgado and Ada Gallegos
Informatics 2023, 10(2), 38; https://doi.org/10.3390/informatics10020038 - 11 Apr 2023
Cited by 7 | Viewed by 6140
Abstract
The COVID-19 pandemic and the boom of fake news cluttering the internet have revealed the power of social media today. However, young people are not yet aware of their role in the digital age, even though they are the main users of social [...] Read more.
The COVID-19 pandemic and the boom of fake news cluttering the internet have revealed the power of social media today. However, young people are not yet aware of their role in the digital age, even though they are the main users of social media. As a result, the belief that older adults are responsible for information is being re-evaluated. In light of this, the present study was aimed at identifying the factors associated with the spread of fake news among young people in Medellín (Colombia). A total of 404 self-administered questionnaires were processed in a sample of people between the ages of 18 and 34 and analyzed using statistical techniques, such as exploratory factor analysis and structural equation modeling. The results suggest that the instantaneous sharing of fake news is linked to people’s desire to raise awareness among their inner circle, particularly when the messages shared are consistent with their perceptions and beliefs, or to the lack of time to properly verify their accuracy. Finally, passive corrective actions were found to have a less significant impact in the Colombian context than in the context of the original model, which may be explained by cultural factors. Full article
(This article belongs to the Collection Uncertainty in Digital Humanities)
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15 pages, 4006 KiB  
Article
Study on Dynamic Response of Damper under Gas Explosion Impact
by Shujuan Li, Zhenzhen Jia and Qing Ye
Sustainability 2023, 15(4), 3356; https://doi.org/10.3390/su15043356 - 12 Feb 2023
Cited by 9 | Viewed by 1700
Abstract
Mine ventilation provides fresh air to underground workers. The dampers can provide a qualified fresh air to each demand workplace by adjusting the air volume, which can ensure workers’ health. However, the powerful impact damage caused by gas explosions in the roadway can [...] Read more.
Mine ventilation provides fresh air to underground workers. The dampers can provide a qualified fresh air to each demand workplace by adjusting the air volume, which can ensure workers’ health. However, the powerful impact damage caused by gas explosions in the roadway can lead to deformation and damage to the dampers and even cause the breakdown of the ventilation system. At the same time, the impact effects of gas explosions may cause worker fatalities. For this reason, the dynamic response of gas explosions to dampers and their effects need to be studied. Based on the analysis of the damper construction and the damage characteristics of the gas explosion, ANSYS/LS-DYNA software is used to establish a mathematical-physical model of the damper with ventilation-regulating windows of six different sizes. The reliability of the model is verified by comparing the simulated pressure values with the values calculated by the Sadowski equation. The dynamic response characteristics of the dampers under the gas explosion impact are simulated and the displacement, equivalent stress and effective plastic strain of the dampers are measured. Finally, a theoretical analysis is carried out. The study results show that the displacement of the damper increases gradually from the edge to the center and the deformation is symmetrical in the absence of the ventilation-regulating window. The deformation region below the ventilation-regulating window is more obvious when the ventilation-regulating window is installed. The maximum stress of the damper first appears at the four corners of the damper, the stress of the unit at this position increases with the increase of the side length of the ventilation-regulating window. The stress of the unit in the lower left corner of the ventilation-regulating window first increases and then decreases with the increase of the side length of the ventilation-regulating window, and all the stresses of the units first increase and then decrease, and finally, the stresses basically approach a stable value. From the instantaneous ignition to the completion of the final reaction, the plastic strain gradually increases, but the area of the plastic strain region gradually decreases. The damage and deformation of the damper are basically consistent with the situation of the damper in the explosion accident. The research results can provide some theoretical basis and data support for the damper structure selection, damper location selection and setting of ventilation-regulating window. Full article
(This article belongs to the Special Issue Mining Risk and Safety Management)
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18 pages, 8762 KiB  
Article
Investigation on Distributed Vibration Damping of Bridge Based on Energy Harvesting Technique and Finite Element Analysis
by Hailu Yang, Qun Chen, Huifang Liu, Haoran Chang, Shih-Hsien Yang, Linbing Wang and Pengfei Liu
Appl. Sci. 2023, 13(1), 382; https://doi.org/10.3390/app13010382 - 28 Dec 2022
Cited by 1 | Viewed by 1981
Abstract
Based on the vibration control method and energy harvesting principle in the bridge field, this paper proposes a distributed vibration reduction and energy harvesting method for bridges. Firstly, the analytical solutions of the induced electromotive force, output power and magnetic damping generated by [...] Read more.
Based on the vibration control method and energy harvesting principle in the bridge field, this paper proposes a distributed vibration reduction and energy harvesting method for bridges. Firstly, the analytical solutions of the induced electromotive force, output power and magnetic damping generated by a coil in a magnetic field were deduced through an electromagnetic theory analysis. In addition, the structural vibration equation under the magnetic damping was deduced. Then, a new method of joint simulation and modeling analysis of vibration and energy output was proposed. Finally, the structural vibration reduction and energy output power were analyzed and calculated. The main research results are as follows: by calculating the instantaneous power of the energy collection of the designed circuit, the average instantaneous power collected by the design method is 1.093 × 10−9 W; the initial vibration signal of the target node is obtained through analysis, and the vibration signal of the node before and after applying the electromagnetic damping force is transformed. For the energy analysis, the energy of the acceleration curve before and after the node was calculated to be 3.1048 × 108 and 3.1044 × 108, respectively, and the reduction rate of the node vibration energy was 0.01% and 0.02%, respectively. Thus, the feasibility and vibration reduction effect of the designed bridge distributed vibration reduction and energy harvesting method is verified when the electromagnetic damping force is small. This method can provide new ideas for bridge structure vibration reduction and energy harvesting research and is of great significance to the infrastructure construction and utilization of renewable energy. Full article
(This article belongs to the Special Issue State-of-the-Art in Energy Harvesting for IoT and WSN)
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15 pages, 4169 KiB  
Article
Parameterized Instantaneous Frequency Estimation Method for Vibration Signal with Nonlinear Frequency Modulation
by Yuexin Huang, Qiukun Zhang, Jianfeng Zhong, Zhixiong Chen and Shuncong Zhong
Machines 2022, 10(9), 777; https://doi.org/10.3390/machines10090777 - 6 Sep 2022
Cited by 4 | Viewed by 1944
Abstract
The vibration signal from the rotatory machinery condition monitoring under time-varying speed is usually amplitude-modulated (AM) and frequency-modulated (FM). It is important to efficiently and accurately estimate the instantaneous frequency (IF) of the vibration signal. In this paper, a novel parameterized IF estimation [...] Read more.
The vibration signal from the rotatory machinery condition monitoring under time-varying speed is usually amplitude-modulated (AM) and frequency-modulated (FM). It is important to efficiently and accurately estimate the instantaneous frequency (IF) of the vibration signal. In this paper, a novel parameterized IF estimation method is proposed. The method employs a high-order polynomial function to approximate the nonlinear IF and subsequently constructs overdetermined systems of linear equations by calculating the Fourier transform of the derivative of the signal. The IF can be estimated by using least squares estimation to solve the equations. The proposed method has high computational efficiency because it can obtain the estimation of IF over a period of time simultaneously; it differs from traditional time-frequency analysis methods that need to calculate the IF at each point in the time axis. It is demonstrated that the proposed method is not only particularly powerful for the nonlinear FM mono-component signal but also applicable to the multi-component signal constructed by multiple harmonics. The numerical simulation validates the effectiveness of the proposed method, and the experiment’s results show that the method is suitable for the IF estimation of the vibration signal from the varying-speed rotor system. Full article
(This article belongs to the Section Machine Design and Theory)
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17 pages, 1014 KiB  
Article
Energy Consumption Prediction and Analysis for Electric Vehicles: A Hybrid Approach
by Hamza Mediouni, Amal Ezzouhri, Zakaria Charouh, Khadija El Harouri, Soumia El Hani and Mounir Ghogho
Energies 2022, 15(17), 6490; https://doi.org/10.3390/en15176490 - 5 Sep 2022
Cited by 29 | Viewed by 5752
Abstract
Range anxiety remains one of the main hurdles to the widespread adoption of electric vehicles (EVs). To mitigate this issue, accurate energy consumption prediction is required. In this study, a hybrid approach is proposed toward this objective by taking into account driving behavior, [...] Read more.
Range anxiety remains one of the main hurdles to the widespread adoption of electric vehicles (EVs). To mitigate this issue, accurate energy consumption prediction is required. In this study, a hybrid approach is proposed toward this objective by taking into account driving behavior, road conditions, natural environment, and additional weight. The main components of the EV were simulated using physical and equation-based models. A rich synthetic dataset illustrating different driving scenarios was then constructed. Real-world data were also collected using a city car. A machine learning model was built to relate the mechanical power to the electric power. The proposed predictive method achieved an R2 of 0.99 on test synthetic data and an R2 of 0.98 on real-world data. Furthermore, the instantaneous regenerative braking power efficiency as a function of the deceleration level was also investigated in this study. Full article
(This article belongs to the Section E: Electric Vehicles)
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19 pages, 4427 KiB  
Article
Squeezing Mechanical Analysis and Model Establishment of the Viscoelastic Rubber-Strip-Feeding Process of the Cold-Feed Rubber Extruder
by Yanchang Liu, Yiren Pan, Xuehua Hu and Fang Yu
Polymers 2022, 14(17), 3602; https://doi.org/10.3390/polym14173602 - 31 Aug 2022
Cited by 2 | Viewed by 3575
Abstract
In the process of rubber extrusion, the feed structure directly affects the extrusion quality, extrusion uniformity, screw lateral force, and feed power consumption. Until now, the feed structure was mainly based on empirical designs, and there was no theoretical model for the optimal [...] Read more.
In the process of rubber extrusion, the feed structure directly affects the extrusion quality, extrusion uniformity, screw lateral force, and feed power consumption. Until now, the feed structure was mainly based on empirical designs, and there was no theoretical model for the optimal design of a feed structure. This paper focused on the squeezing mechanical analysis and model establishment of the feeding process in which viscoelastic rubber strips are passed through feed-wedge clearance in cold-feed extruders. The screw flight rotation squeezing process was simplified into a disc rotation squeezing process; the instantaneous squeezing velocity h˙(t) in the disc rotation squeezing model was derived according to feed wedge clearance geometry and the disc rotating speed. By transforming rotation squeezing into differential slab squeezing, mathematical expressions of the velocity distribution, pressure distribution, total squeezing force, and power consumption in the feeding process were derived in a rectangular coordinate system under isothermal and quasi-steady assumptions and certain boundary conditions by using balance equations and a Newtonian viscous constitutive relation. Theoretical calculations and experimental values showed the same trend. Through comparison, it was found that the power consumption (P3) caused by sliding friction is about 200–900 W according to theoretical calculations, while the experimental test results show it to be about 300–700 W. Additionally, the difference between theoretical pressure value and the experimental pressure value can be controlled within 5–15%. This could reflect the main factors that affect the feeding process, so could be used for analyses of actual feeding problems, and to contribute to rough quantitative descriptions of the feeding process, finite element simulation, and the optimization of the feeding structure. Full article
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14 pages, 12109 KiB  
Article
A Novel Excitation Approach for Power Transformer Simulation Based on Finite Element Analysis
by Wen-Ching Chang and Cheng-Chien Kuo
Appl. Sci. 2021, 11(21), 10334; https://doi.org/10.3390/app112110334 - 3 Nov 2021
Cited by 4 | Viewed by 2817
Abstract
Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the [...] Read more.
Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the power transformer, the design value of the magnetic flux density in the core is important, and it affects the efficiency, cost, and life cycle. Therefore, this paper uses the software of ANSYS Maxwell to solve the instantaneous magnetic flux density distribution, core loss distribution, and total iron loss of the iron core based on the finite element method in the time domain. In addition, a new external excitation equation is proposed. The new external excitation equation can improve the accuracy of the simulation results and reduce the simulation time. Finally, the three-phase five-limb transformer is developed, and actually measures the local magnetic flux density and total core loss to verify the feasibility of the proposed finite element method of model and simulation parameters. Full article
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19 pages, 1338 KiB  
Article
Generalised Asymptotic Solutions for the Inflaton in the Oscillatory Phase of Reheating
by Gabriel Álvarez, Luis Martínez Alonso and Elena Medina
Universe 2021, 7(10), 390; https://doi.org/10.3390/universe7100390 - 19 Oct 2021
Cited by 1 | Viewed by 1719
Abstract
We determine generalised asymptotic solutions for the inflaton field, the Hubble parameter, and the equation-of-state parameter valid during the oscillatory phase of reheating for potentials that close to their global minima behave as even monomial potentials. For the quadratic potential, we derive a [...] Read more.
We determine generalised asymptotic solutions for the inflaton field, the Hubble parameter, and the equation-of-state parameter valid during the oscillatory phase of reheating for potentials that close to their global minima behave as even monomial potentials. For the quadratic potential, we derive a generalised asymptotic expansion for the inflaton with respect to the scale set by inverse powers of the cosmic time. For the quartic potential, we derive an explicit, two-term generalised asymptotic solution in terms of Jacobi elliptic functions, with a scale set by inverse powers of the square root of the cosmic time. In the general case, we find similar two-term solutions where the leading order term is defined implicitly in terms of the Gauss hypergeometric function. The relation between the leading terms of the instantaneous equation-of-state parameter and different averaged values is discussed in the general case. Finally, we discuss the physical significance of the generalised asymptotic solutions in the oscillatory regime and their matching to the appropriate solutions in the thermalization regime. Full article
(This article belongs to the Special Issue Studying the Universe from Spain)
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30 pages, 18238 KiB  
Article
A Unified Control Strategy of Distributed Generation for Grid-Connected and Islanded Operation Conditions Using an Artificial Neural Network
by Karim M. El-Sharawy, Hatem Y. Diab, Mahmoud O. Abdelsalam and Mostafa I. Marei
Sustainability 2021, 13(11), 6388; https://doi.org/10.3390/su13116388 - 4 Jun 2021
Cited by 2 | Viewed by 5291
Abstract
This article presents a control strategy that enables both islanded and grid-tied operations of a three-phase inverter in distributed generation. This distributed generation (DG) is based on a dramatically evolved direct current (DC) source. A unified control strategy is introduced to operate the [...] Read more.
This article presents a control strategy that enables both islanded and grid-tied operations of a three-phase inverter in distributed generation. This distributed generation (DG) is based on a dramatically evolved direct current (DC) source. A unified control strategy is introduced to operate the interface in either the isolated or grid-connected modes. The proposed control system is based on the instantaneous tracking of the active power flow in order to achieve current control in the grid-connected mode and retain the stability of the frequency using phase-locked loop (PLL) circuits at the point of common coupling (PCC), in addition to managing the reactive power supplied to the grid. On the other side, the proposed control system is also based on the instantaneous tracking of the voltage to achieve the voltage control in the standalone mode and retain the stability of the frequency by using another circuit including a special equation (wt = 2πft, f = 50 Hz). This utilization provides the ability to obtain voltage stability across the critical load. One benefit of the proposed control strategy is that the design of the controller remains unconverted for other operating conditions. The simulation results are added to evaluate the performance of the proposed control technology using a different method; the first method used basic proportional integration (PI) controllers, and the second method used adaptive proportional integration (PI) controllers, i.e., an Artificial Neural Network (ANN). Full article
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20 pages, 7733 KiB  
Article
Improved PR Control Strategy for an LCL Three-Phase Grid-Connected Inverter Based on Active Damping
by Yahui Li, Jing Zhang, Zhenghang Hao and Peng Tian
Appl. Sci. 2021, 11(7), 3170; https://doi.org/10.3390/app11073170 - 2 Apr 2021
Cited by 14 | Viewed by 3992
Abstract
Aiming at the problem of power coupling and complicated decoupling in the d-q coordinate system of a three-phase grid-connected inverter, a current closed-loop control strategy based on an improved QPIR (quasi-proportional integral resonant) controller in the α-β two-phase static [...] Read more.
Aiming at the problem of power coupling and complicated decoupling in the d-q coordinate system of a three-phase grid-connected inverter, a current closed-loop control strategy based on an improved QPIR (quasi-proportional integral resonant) controller in the α-β two-phase static coordinate system is proposed. Firstly, the mathematical model of an LCL three-phase grid-connected inverter is established, and its instantaneous power calculation equation is deduced. Secondly, the frequency method is applied to compare and analyze the proportional resonant, quasi-proportional resonant, and improved current controller, and the appropriate improved controller parameters are obtained according to the traditional proportional integral controller parameter design method and the weight coefficient. Finally, the improved controller is compared with the traditional controller in the simulation model of the LCL three-phase grid-connected inverter based on active damping. The results show that the proposed improved current control strategy has good dynamic response characteristics, can realize the non-static error control of grid-connected current, and realizes the decoupling control of active power and reactive power when the load jumps. At the same time, the results also prove the superiority of the proposed control strategy and verify its effectiveness. Full article
(This article belongs to the Special Issue Electric Power Applications)
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