AC and DC Power Grids System Technologies: Analysis, Control and Practical Applications

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Energy Systems".

Deadline for manuscript submissions: closed (30 March 2024) | Viewed by 15708

Special Issue Editors


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Guest Editor
Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
Interests: battery management system; cloud management; distributed energy storage system; X-ray power design; short-pulse power converter for plasma
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Electrical Engineering, National Chin-Yi University of Technology, Taichung 41170, Taiwan
Interests: power systems; renewable energy; artificial intelligence; fault diagnosis; optimization algorithm
Special Issues, Collections and Topics in MDPI journals

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Co-Guest Editor
Undergraduate Program of Vehicle and Energy Engineering, National Taiwan Normal University, Taipei 10610, Taiwan
Interests: solar power; maximum power point tracking algorithm; rail vehicle auxiliary power system; power quality
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, AC and DC power grids and renewable energy issues in many countries have necessitated increases in the proportion of renewable energy capacity in power systems and a reduction in the dependence on thermal power generation following the rise of environmental awareness. However, the rapid increase in the penetration of intermittent renewable energy and various power generation combination will impact the existing power systems; it is essential to consider the latest advanced technologies with artificial intelligence for AC and DC power grids and renewable energy systems to realize the energy transition. To overcome the challenges mentioned above and allow renewable energy to integrate safely into the power systems, the proposed issue needs state-of-the-art research in AI-related technologies for power systems and must be considered to enhance the safe operation of the system and increase the flexibility of AC and DC power grids.

This issue deals with new technologies for artificial intelligence and advanced technologies for power systems and renewable energy systems, including state-of-the-art research in AC and DC power grids, renewable energy technologies, artificial intelligence, high power DC/DC converters, power electronics converters, fault detection and diagnostics, intelligent power systems and grids, power and energy systems, AI-based methods, sensor-based control, battery energy storage system, vehicle-to-grid, and grid-to-vehicle. These studies are established to improve the strength of power and renewable systems.

In this issue, we sincerely invite the submission of original research results regarding artificial intelligence and advanced power and renewable energy systems technologies. Potential topics of interest for publication include but are not limited to the following:

  • AC and DC Power Grids
  • High Power DC/DC Converters
  • Multi-terminal HVDC Converter Control and Protection
  • DC Technology at Medium and Low Voltage
  • Strategies for AC and DC Fault Ride-Through
  • Other Converter Topologies
  • Smart Grids
  • Renewable Energy Technologies
  • Photovoltaic and Wind Energy Technologies
  • Fault Detection and Diagnostics
  • AI-based Methods
  • Sensor-based Control
  • Big Data and Machine Learning
  • Intelligent Control and Applications
  • Battery Energy Storage System
  • Power Electronics and Motor Control Technology for Vehicles
  • Energy Saving Technology for Building and Air Conditioning
  • Other Related Technologies and Applications

Prof. Dr. Chang-Hua Lin
Dr. Shiue-Der Lu
Dr. Hwa-Dong Liu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • AC and DC power grids
  • power converter
  • HVDC
  • energy management systems
  • energy storage technologies
  • smart grid and microgrid
  • machine learning
  • sustainable electrical energy systems
  • renewable energy technologies
  • energy storage system
  • vehicle-to-grid
  • grid-to-vehicle
  • energy saving

Published Papers (14 papers)

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Research

16 pages, 2129 KiB  
Article
A Fast Reliability Evaluation Strategy for Power Systems under High Proportional Renewable Energy—A Hybrid Data-Driven Method
by Jiaxin Zhang, Bo Wang, Hengrui Ma, Yunshuo Li, Meilin Yang, Hongxia Wang and Fuqi Ma
Processes 2024, 12(3), 608; https://doi.org/10.3390/pr12030608 - 19 Mar 2024
Viewed by 530
Abstract
With the increasing scale of the power system, the increasing penetration of renewable energy, and the increasing uncertainty factors, traditional reliability evaluation methods based on Monte Carlo simulation have greatly reduced computational efficiency in complex power systems and cannot meet the requirements of [...] Read more.
With the increasing scale of the power system, the increasing penetration of renewable energy, and the increasing uncertainty factors, traditional reliability evaluation methods based on Monte Carlo simulation have greatly reduced computational efficiency in complex power systems and cannot meet the requirements of real-time and rapid evaluation. This article proposes a hybrid data-driven strategy to achieve a rapid assessment of power grid reliability on two levels: offline training and online evaluation. Firstly, this article derives explicit analytical expressions for reliability indicators and component parameters, avoiding the computational burden of repetitive Monte Carlo simulation. Next, a large number of samples are quickly generated by parsing expressions to train convolutional neural networks (CNNs), and the system reliability index is quickly calculated under changing operating conditions through CNNs. Finally, the effectiveness and feasibility of the proposed method are verified through an improved RTS-79 testing system. The calculation results show that the method proposed in this article can achieve an online solution of second-level reliability indicators while ensuring calculation accuracy. Full article
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16 pages, 3228 KiB  
Article
Precise Lightning Strike Detection in Overhead Lines Using KL-VMD and PE-SGMD Innovations
by Xinsheng Dong, Jucheng Liu, Shan He, Lu Han, Zhongkai Dong and Minbo Cai
Processes 2024, 12(2), 329; https://doi.org/10.3390/pr12020329 - 02 Feb 2024
Viewed by 459
Abstract
When overhead lines are impacted by lightning, the traveling wave of the fault contains a wealth of fault information. The accurate extraction of feature quantities from transient components and their classification are fundamental to the identification of lightning faults. The extraction process may [...] Read more.
When overhead lines are impacted by lightning, the traveling wave of the fault contains a wealth of fault information. The accurate extraction of feature quantities from transient components and their classification are fundamental to the identification of lightning faults. The extraction process may involve modal aliasing, optimal wavelet base issues, and inconsistencies between the lightning strike distance and the fault point. These factors have the potential to impact the effectiveness of recognition. This paper presents a method for identifying lightning strike faults by utilizing Kullback–Leibler (KL) divergence enhanced Variational Mode Decomposition (VMD) and Symmetric Geometry Mode Decomposition (SGMD) improved with Permutation Entropy (PE) to address the aforementioned issues. A model of a 220 kV overhead line is constructed using real faults to replicate scenarios of winding strike, counterstrike, and short circuit. The three-phase voltage is chosen and then subjected to Karenbaren decoupling in order to transform it into zero mode, line mode 1, and line mode 2. The zero-mode voltage is decomposed using KL-VMD and PE-SGMD methods, and the lightning identification criteria are developed based on various transient energy ratios. The research findings demonstrate that the criteria effectively differentiate between winding strike, counterstrike, and short-circuit faults, thus confirming the accuracy and efficacy of the lightning fault identification criteria utilizing KL-VMD and PE-SGMD. Full article
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22 pages, 19793 KiB  
Article
Control Approach of Grid-Connected PV Inverter under Unbalanced Grid Conditions
by Mohammed Alharbi
Processes 2024, 12(1), 212; https://doi.org/10.3390/pr12010212 - 18 Jan 2024
Viewed by 930
Abstract
In grid-connected photovoltaic (PV) systems, power quality and voltage control are necessary, particularly under unbalanced grid conditions. These conditions frequently lead to double-line frequency power oscillations, which worsen Direct Current (DC)-link voltage ripples and stress DC-link capacitors. The well-known dq frame vector control [...] Read more.
In grid-connected photovoltaic (PV) systems, power quality and voltage control are necessary, particularly under unbalanced grid conditions. These conditions frequently lead to double-line frequency power oscillations, which worsen Direct Current (DC)-link voltage ripples and stress DC-link capacitors. The well-known dq frame vector control technique, which is effective under normal conditions, struggles with oscillatory component management in unbalanced grid conditions. To address this issue, this paper presents an advanced control approach designed for grid-connected PV inverters. The proposed approach is effective at reducing oscillations in the DC-link voltage at double the grid frequency, thereby enhancing system stability and component longevity. This method introduces a feedback control method designed to regulate oscillatory components that appeared within the dq frame and suppress the DC-link voltage oscillations under imbalance conditions, including single line-to-ground (SLG) faults. Additionally, the control scheme incorporates a maximum power point tracking (MPPT) controller to optimize PV efficiency. Comprehensive simulations demonstrate the effectiveness of this method in maintaining sinusoidal current injections and stabilizing DC-link voltage during unbalanced grid conditions. Simulation results show that the control scheme effectively stabilizes DC-link voltage, maintains balanced grid current, and ensures constant active power under various conditions, including SLG faults and solar irradiance changes. Full article
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21 pages, 4860 KiB  
Article
Energy Storage Deployment and Benefits in the Chinese Electricity Market Considering Renewable Energy Uncertainty and Energy Storage Life Cycle Costs
by Yichao Meng, Ze Ye, Lei Chen, Shanshan Huang and Tiantian Li
Processes 2024, 12(1), 130; https://doi.org/10.3390/pr12010130 - 03 Jan 2024
Viewed by 699
Abstract
The construction and development of energy storage are crucial areas in the reform of China’s power system. However, one of the key issues hindering energy storage investments is the ambiguity of revenue sources and the inaccurate estimation of returns. In order to facilitate [...] Read more.
The construction and development of energy storage are crucial areas in the reform of China’s power system. However, one of the key issues hindering energy storage investments is the ambiguity of revenue sources and the inaccurate estimation of returns. In order to facilitate investors’ understanding of revenue sources and returns on investment of energy storage in the existing electricity market, this study has established multiple relevant revenue quantification models. The research methodology employed in this paper consists of three main components: Firstly, we established a revenue model and a cost model for energy storage participation in the electricity market. These models focus on arbitrage revenue, subsidy revenue, auxiliary services revenue, investment cost, operational and maintenance cost, and auxiliary service cost of energy storage. Subsequently, we utilized an enhanced Grey Wolf Optimizer algorithm to solve the optimization problem and maximize revenue, thus obtaining the optimal capacity and revenue scale of energy storage in the electricity market. Finally, we compared the whole-lifecycle ROI of different energy storage options in various scenarios. The evaluation results demonstrate that the difference between peak and off-peak loads impacts the investment demand and charging/discharging depth of energy storage. In addition, the discrepancy between peak and off-peak prices affects the arbitrage return of energy storage. These two factors can serve as criteria for energy storage investors to assess their return expectations. When solely considering economic returns and disregarding technical factors, pumped storage energy storage emerges as the most suitable mechanical energy storage option requiring investment. The main contribution of this study lies in the estimation of the lifecycle investment returns for various energy storage technologies in the Chinese electricity market, thus providing valuable insights for the investment and operational practices of market participants. Full article
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19 pages, 3135 KiB  
Article
Optimal Control of Hybrid Photovoltaic/Thermal Water System in Solar Panels Using the Linear Parameter Varying Approach
by Faycel Jamaaoui, Vicenç Puig and Mounir Ayadi
Processes 2023, 11(12), 3426; https://doi.org/10.3390/pr11123426 - 13 Dec 2023
Viewed by 756
Abstract
During photovoltaic (PV) conversion in solar panels, a part of the solar radiation is not converted to electricity by the cells, producing heat that could increase their temperature. This increase in temperature deteriorates the performance of the PV panel. In this paper, a [...] Read more.
During photovoltaic (PV) conversion in solar panels, a part of the solar radiation is not converted to electricity by the cells, producing heat that could increase their temperature. This increase in temperature deteriorates the performance of the PV panel. In this paper, a hybrid PV/thermal (PV/T) water system is proposed to mitigate this problem. This system combines a PV panel and a thermal collector. In this paper, we focused on the modeling and control of this hybrid system in the linear parameter varying (LPV) framework. An optimal linear quadratic regulator (LQR) is proposed to control the PV cell temperature around an optimal value that maximises electricity generation. Since the system model is nonlinear, an optimal LQR gain-scheduling state-feedback control approach based on an LPV representation of the nonlinear model is designed using the Linear Matrix Inequality (LMI) method. The goal is to obtain the maximum electrical power for each solar panel. Since a reduced number of sensors is available, an LPV Kalman filter is also proposed to estimate the system states required by the state-feedback controller. The obtained results in a laboratory setup in simulation are used to assess the proposed approach, showing promise in terms of control performance of the PV/T system. Full article
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14 pages, 1974 KiB  
Article
Mobile Energy Storage System Scheduling Strategy for Improving the Resilience of Distribution Networks under Ice Disasters
by Xiaofang Guo, Guixi Miao, Xin Wang, Liang Yuan, Hengrui Ma and Bo Wang
Processes 2023, 11(12), 3339; https://doi.org/10.3390/pr11123339 - 30 Nov 2023
Viewed by 820
Abstract
The distribution system is easily affected by extreme weather, leading to an increase in the probability of critical equipment failures and economic losses. Actively scheduling various resources to provide emergency power support can effectively reduce power outage losses caused by extreme weather. This [...] Read more.
The distribution system is easily affected by extreme weather, leading to an increase in the probability of critical equipment failures and economic losses. Actively scheduling various resources to provide emergency power support can effectively reduce power outage losses caused by extreme weather. This paper proposes a mobile energy storage system (MESS) scheduling strategy for improving the resilience of distribution networks under ice disasters. First, the influence of wind and ice loads on power transmission lines is analyzed, and a detailed fault statistical model of transmission lines under an ice disaster is established. Then, the MESS scheduling problem considering the coupling of transportation-distribution networks is transformed into a two-stage optimization problem. The first stage determines the optimal configuration scheme for MESS, and in the second stage, the optimal path selection for MESS can be obtained. Finally, the effectiveness and feasibility of the algorithm proposed in this paper are verified through an improved IEEE-33 node testing system. Full article
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21 pages, 17992 KiB  
Article
Reduction in the Number of Current Sensors of a Semi-Bridgeless PFC Rectifier Based on GaNFET Characteristics
by Chen-Bin Yu and Kuo-Ing Hwu
Processes 2023, 11(12), 3259; https://doi.org/10.3390/pr11123259 - 21 Nov 2023
Viewed by 699
Abstract
The semi-bridgeless power factor correction (PFC) rectifier is widely used due to its high power factor, high efficiency, and low electromagnetic interference. However, in this rectifier, the inductor current will flow through the body diode of the metal–oxide–semiconductor field-effect transistor (MOSFET) when the [...] Read more.
The semi-bridgeless power factor correction (PFC) rectifier is widely used due to its high power factor, high efficiency, and low electromagnetic interference. However, in this rectifier, the inductor current will flow through the body diode of the metal–oxide–semiconductor field-effect transistor (MOSFET) when the MOSFET does not work, causing a problem in detecting the inductor current. Consequently, the current transformers are generally used as current sensors. This means that using many current sensors will make the cost and the peripheral detection circuit complicated. In this paper, our new method is to use a gallium nitride field-effect transistor (GaNFET) to replace the metal–oxide–semiconductor field-effect transistor (MOSFET) in the main switch selection. The reverse-biased conduction voltage of the third quadrant of the GaNFET is higher than the forward-biased conduction voltage of the diode, which solves the problem in detecting the inductor current, reduces the number of current sensors, and simplifies the corresponding peripheral circuits and components. Eventually, via mathematical deduction and hardware implementation, a semi-bridgeless PFC prototype with a GaNFET was built to verify the effectiveness of the proposed structure. Full article
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13 pages, 4316 KiB  
Article
An Improved Dual Second-Order Generalized Integrator Phased-Locked Loop Strategy for an Inverter of Flexible High-Voltage Direct Current Transmission Systems under Nonideal Grid Conditions
by Lai Peng, Zhichao Fu, Tao Xiao, Yang Qian, Wei Zhao and Cheng Zhang
Processes 2023, 11(9), 2634; https://doi.org/10.3390/pr11092634 - 04 Sep 2023
Cited by 1 | Viewed by 680
Abstract
High-voltage flexible power systems, with their intrinsic characteristics, play an increasingly important role in electronic power systems. Synchronization between the inverter and the grid needs to be achieved by a phase-locked loop (PLL), the performance of which determines the quality of power transmission. [...] Read more.
High-voltage flexible power systems, with their intrinsic characteristics, play an increasingly important role in electronic power systems. Synchronization between the inverter and the grid needs to be achieved by a phase-locked loop (PLL), the performance of which determines the quality of power transmission. This paper proposes a PLL adapted to extremely harsh grid conditions. Firstly, the traditional synchronous reference frame PLL and the dual second-order generalized integrator (DSOGI-PLL) are analyzed, and the errors in phase-locking and the shortcomings of these two methods in the presence of DC components in the grid are pointed out. Secondly, based on the harmonic grid voltage, a repetitive control internal model is introduced by DSOGI to realize the real-time tracking and regulation of the harmonic signals in order to suppress the harmonic voltage disturbance. In addition, a DC bias elimination and frequency adaptive method is proposed to solve the problems of DC bias and grid voltage frequency fluctuation in order to achieve adaptive tracking of the grid phase. Finally, the superiority of the proposed strategy is verified through simulations and experiments. Full article
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23 pages, 8555 KiB  
Article
Exponential Curve-Based Control Strategy for Auxiliary Equipment Power Supply Systems in Railways
by Shoeb Azam Farooqui, Chang-Hua Lin, Shiue-Der Lu, Hwa-Dong Liu, Adil Sarwar and Liang-Yin Huang
Processes 2023, 11(4), 1285; https://doi.org/10.3390/pr11041285 - 20 Apr 2023
Cited by 1 | Viewed by 1400
Abstract
An exponential curve-based (ECB) control strategy has been proposed in this paper. The proposed ECB control strategy is based on the growth and decay of charge in the series RC circuit and the harmonic elimination by detecting the Fourier expansion series of the [...] Read more.
An exponential curve-based (ECB) control strategy has been proposed in this paper. The proposed ECB control strategy is based on the growth and decay of charge in the series RC circuit and the harmonic elimination by detecting the Fourier expansion series of the auxiliary equipment power supply system’s (AEPSS) three-phase output voltage level. It can quickly adjust each duty cycle to the best value for driving the isolated three-phase inverter (ITPI) and produce a three-phase 380 VAC/60 Hz output. A comparison of the AEPSS output performance using the traditional voltage cancellation method (VCM) and the proposed ECB control strategy was performed. The hardware implementation of the system was performed on the prototype developed in the laboratory. These control strategies are tested under three conditions, i.e., (i) Vi = 550 VDC. (ii) Vi = 750 VDC. (iii) Vi = 800 VDC. The total harmonic distortion (THD) is 13.7%, 14.5%, and 14.9%, and the output voltage Vo is 372.3 VAC, 377.3 VAC, and 385.3 VAC using the traditional control strategy at three test conditions, respectively. However, the THD is 7.2%, 7.8%, and 8.0%, and the output voltage Vo is 382.2 VAC, 381.2 VAC, and 381.9 VAC using the proposed ECB control strategy under the test conditions. It is obvious from the hardware results that the output voltage harmonics and output voltage level for the proposed ECB control strategy are superior to the traditional VCM. The voltage produced from the AEPSS using the proposed ECB control strategy is more stable and has better quality. In addition, the filter size is also reduced. Full article
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19 pages, 2625 KiB  
Article
Power and Energy Management Strategies for a Microgrid with the Presence of Electric Vehicles and CAES Considering the Uncertainty of Resources
by Reza Doosti, Alireza Rezazadeh and Mostafa Sedighizadeh
Processes 2023, 11(4), 1156; https://doi.org/10.3390/pr11041156 - 10 Apr 2023
Viewed by 1657
Abstract
We are witnessing the growth of microgrid technology and the development of electric vehicles (EVs) in the world. These microgrids seek demand response (DR) and energy storage for better management of their resources. In this research, microgrids, including wind turbines, photovoltaics, battery charging/discharging, [...] Read more.
We are witnessing the growth of microgrid technology and the development of electric vehicles (EVs) in the world. These microgrids seek demand response (DR) and energy storage for better management of their resources. In this research, microgrids, including wind turbines, photovoltaics, battery charging/discharging, and compressed air energy storage (CAES), are considered. We will consider two scenarios under uncertainty: (a) planning a microgrid and DR without considering CAES, and (b) planning a microgrid and DR considering CAES. The cost of charging the battery in the second study decreased by $0.66 compared to the first study. The battery is charged with a difference of $0.7 compared to the case of the first study. We will also pay for unsupplied energy and excess energy in this microgrid. Then, we test the scheduling of vehicles to the grid (V2G) in the IEEE 33-bus network. The first framework for increasing network flexibility is the use of EVs as active loads. The scheduling of vehicles in the IEEE 33-bus network is simulated. Every hour, plug-in hybrid electric vehicle (PHEV) charging and discharging, active power loss, and cost will be compared with IHS and PSO algorithms. The difference obtained using the IHS algorithm compared to the PSO algorithm is 1.002 MW and the voltage difference is 9.14 pu. Full article
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23 pages, 6561 KiB  
Article
A Novel Isolated Intelligent Adjustable Buck-Boost Converter with Hill Climbing MPPT Algorithm for Solar Power Systems
by Bushra Sabir, Shiue-Der Lu, Hwa-Dong Liu, Chang-Hua Lin, Adil Sarwar and Liang-Yin Huang
Processes 2023, 11(4), 1010; https://doi.org/10.3390/pr11041010 - 27 Mar 2023
Cited by 6 | Viewed by 1596
Abstract
This study proposes a new isolated intelligent adjustable buck-boost (IIABB) converter with an intelligent control strategy that is suitable for regenerative energy systems with unsteady output voltages. It also serves as a reliable voltage source for loads such as battery systems, microgrids, etc. [...] Read more.
This study proposes a new isolated intelligent adjustable buck-boost (IIABB) converter with an intelligent control strategy that is suitable for regenerative energy systems with unsteady output voltages. It also serves as a reliable voltage source for loads such as battery systems, microgrids, etc. In addition, the hill climbing (HC) maximum power point tracking (MPPT) algorithm can be utilized with this innovative IIABB converter to capture the MPP and then enhance system performance. In this converter, five inductors (LA, LB, LC, LD, and LE) and four power MOSFETs (SA, SB, SC, and SD) are used in the proposed novel isolated intelligent adjustable buck-boost (IIABB) converter to adjust the applied voltage across the load side. It also has a constant, stable output voltage. The new IIABB converter is simulated and verified using MATLAB R2021b, and the performances of the proposed IIABB converter and conventional SEPIC converter are compared. The solar photovoltaic module output voltages of 20 V, 30 V, and 40 V are given as inputs to the proposed IIABB converter, and the total output voltage of the proposed converter is 48 V. In the new IIABB converter, the duty cycle of the power MOSFET has a small variation. The proposed IIABB converter has an efficiency of 92~99%. On the other hand, in the conventional SEPIC converter, the duty cycle of a power MOSFET varies greatly depending on the relationship between the output and input voltage, which deteriorates the efficiency of the converter. As a result, this research contributes to the development of a novel type of IIABB converter that may be employed in renewable energy systems to considerably increase system performance and reduce the cost and size of the system. Full article
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15 pages, 3191 KiB  
Article
Grid-Connected Microbial Fuel Cell Modeling and Control in Distributed Generation
by Fangmei Jiang, Liping Fan, Weimin Zhang and Naitao Yang
Processes 2023, 11(2), 466; https://doi.org/10.3390/pr11020466 - 03 Feb 2023
Viewed by 1190
Abstract
Water shortages and water pollution have seriously threatened the sustainable development of the community. The grid-connected microbial fuel cell is an effective way to control the cost of wastewater treatment plants. Moreover, it solves the problem of low efficiency and high energy consumption. [...] Read more.
Water shortages and water pollution have seriously threatened the sustainable development of the community. The grid-connected microbial fuel cell is an effective way to control the cost of wastewater treatment plants. Moreover, it solves the problem of low efficiency and high energy consumption. In view of the characteristics of strong coupling, non-linearity, and internal load in the process of microbial fuel cell grid connection, it is necessary to design the grid-connected unit of power electronic device. Based on the establishment of the microbial fuel cell stack model, the stability control and the constant power control scheme were designed for the chopper and inverter, respectively. The simulation results showed that the control strategy with the combination of voltage stabilizer and constant power can make a grid-connected system of all phase voltage and frequency output. The three-phase voltage Uabc was steady at 7 h and the voltage amplitude was controlled at roughly 380 V, according to the output voltage waveform. The value was 50 Hz, which satisfies the criteria for grid connection. Full article
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15 pages, 1543 KiB  
Article
A Modified Multiparameter Linear Programming Method for Efficient Power System Reliability Assessment
by Jing Zuo, Sui Peng, Yan Yang, Zuohong Li, Zhengmin Zuo, Hao Yu and Yong Lin
Processes 2022, 10(11), 2188; https://doi.org/10.3390/pr10112188 - 25 Oct 2022
Cited by 4 | Viewed by 1130
Abstract
Power systems face adequacy risks because of the high integration of renewable energy. It is urgent to develop efficient methods for power system operational reliability assessment. Conventional power system reliability assessment methods cannot achieve real-time assessment of system risk because of the high [...] Read more.
Power systems face adequacy risks because of the high integration of renewable energy. It is urgent to develop efficient methods for power system operational reliability assessment. Conventional power system reliability assessment methods cannot achieve real-time assessment of system risk because of the high computational complexity and long calculation time. The high computational complexity is mainly caused by a large number of optimal power flow (OPF) calculations. To reduce the computational complexity, this paper transfers the optimal power flow model as a multiparameter linear programming model. Then, the optimal power flow can be obtained by linear calculations. Furthermore, this paper proposes a state reduction method considering the importance index of transmission lines for further improving the calculation efficiency. Case studies are carried out on IEEE standard systems and a provincial power grid in China. Compared with the conventional reliability assessment method, the reliability assessment efficiency of the proposed method increases by 10–40 times, and the assessment error is less than 1%. Full article
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15 pages, 6171 KiB  
Article
The Total Low Frequency Oscillation Damping Method Based on Interline Power Flow Controller through Robust Control
by Jingbo Zhao, Ke Xu, Zheng Li, Shengjun Wu and Dajiang Wang
Processes 2022, 10(10), 2064; https://doi.org/10.3390/pr10102064 - 12 Oct 2022
Cited by 2 | Viewed by 1196
Abstract
The interline power flow controller (IPFC) can control the active power and reactive power of different lines in power system. To utilize the flexible control ability of IPFC and increase the damping characteristic of its controller AC system, this paper proposes a low-frequency [...] Read more.
The interline power flow controller (IPFC) can control the active power and reactive power of different lines in power system. To utilize the flexible control ability of IPFC and increase the damping characteristic of its controller AC system, this paper proposes a low-frequency oscillation (LFO) suppress method through IPFC. The LFO suppress method is designed by adding supplementary signals to the outer current control loop of IPFC. In addition to adding supplementary active power signals, the reactive supplementary signals are also added to related control loop, which is the total control scheme. To obtain the power system’s small signal model, the identification technology based on the PRONY algorithm is used. In addition, the robust control theory is also applied to make the controllers more adaptive. To verify the effectiveness of the proposed method, two controllers including both the active and reactive controllers are designed for in PSCAD software. Furthermore, the simulation results prove the proposed method can reach a better control effect and is also of robustness. Full article
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