Optimization Methods for Energy System StudiesS.M. Masum Ahmed (ESR14)This is to certify that S.M. Masum Ahmed completed the “Optimization Methods for Energy System Studies" course held from April 2nd to April 12th. S.M. Masum Ahmed has actively engaged in the course activities and has exhibited a high level of proficiency in understanding and applying optimization techniques. This course is equivalent to 2 ECTS credits.
Type: Local Training Course
Date: 2024-04-16
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ENERGY AND ENVIRONMENTAL ECONOMICS AND POLICYKonstantinos Pantazis (ESR15)The course Energy and Environmental Economics and Policy at Bocconi University aimed to explore the economic and policy aspects of energy and environmental issues. Its mission was to provide insights into the interplay between energy markets, environmental sustainability, and regulatory frameworks, equipping participants with the analytical tools necessary to assess and design effective policies in these domains. The mission of the course are describing bellow: "The European Union explicitly states that “since economics is about to deal with scarce resources, it can often be useful when tackling environmental problems”. This statement comes from a precise observation. The ability of the natural environment to dispose the waste of anthropogenic activities (keeping unchanged degree of regeneration) is not infinite (downstream “scarcity”). This kind of “scarcity” justifies to use the tools of the economic theory to face environmental problems. In this regard, two circumstances should be adequately emphasised. Firstly, today the most important (at least perceived) environmental problem is climate change due to the anthropogenic emissions of carbon dioxide. Secondly, more than 80% of carbon emissions are due to energy production and consumption. As a consequence, fighting climate change requires to adequately study the interaction between energy and environmental issues with the aim to understand how to mitigate global warming through (but not only) the decarbonisation of energy supply. The analysis of this interaction is the principal mission of this course." |
ENERGY AND ENVIRONMENTAL ECONOMICS AND POLICYS.M. Masum Ahmed (ESR14)The course Energy and Environmental Economics and Policy at Bocconi University aimed to explore the economic and policy aspects of energy and environmental issues. Its mission was to provide insights into the interplay between energy markets, environmental sustainability, and regulatory frameworks, equipping participants with the analytical tools necessary to assess and design effective policies in these domains. The mission of the course are describing bellow: "The European Union explicitly states that “since economics is about to deal with scarce resources, it can often be useful when tackling environmental problems”. This statement comes from a precise observation. The ability of the natural environment to dispose the waste of anthropogenic activities (keeping unchanged degree of regeneration) is not infinite (downstream “scarcity”). This kind of “scarcity” justifies to use the tools of the economic theory to face environmental problems. In this regard, two circumstances should be adequately emphasised. Firstly, today the most important (at least perceived) environmental problem is climate change due to the anthropogenic emissions of carbon dioxide. Secondly, more than 80% of carbon emissions are due to energy production and consumption. As a consequence, fighting climate change requires to adequately study the interaction between energy and environmental issues with the aim to understand how to mitigate global warming through (but not only) the decarbonisation of energy supply. The analysis of this interaction is the principal mission of this course."
Type: Local Training Course
Date: 2024-06-30
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Managing Research ProjectsSayeed Hasan (ESR10)Managing Research Projects (MNI9060) [3 credits, mandatory doctoral course offered by TalTech] |
Career DevelopmentSayeed Hasan (ESR10)Career Development (UTT9011) [6 credits, mandatory doctoral course offered by TalTech] |
Academic Writing WorkshopSayeed Hasan (ESR10)Academic Writing Workshop (UTT9102) [3 credits, mandatory doctoral course offered by TalTech] |
Emerging Power Conversion TechnologiesSayeed Hasan (ESR10)Emerging Power Conversion Technologies (EED9130) [6 credits, mandatory doctoral course offered by TalTech] The aim of this course is to enable students to get acquainted with the development of emerging power electronic technologies for efficient conversion of electric energy; to analyze the industry trends and evaluate the prospective applicability of emerging power conversion solutions in the future and evaluate their impact on the industry and society.
Type: Local Training Course
Date: 2024-07-31
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Summer School Certification "Dive into the Cyber-Physical Evolution of Offshore Wind and Distribution Grids"S.M. Masum Ahmed (ESR14)The Summer School (2,5 ECTS) was organized within the H2020 MSCA ITN project InnoCyPES Topics & Content of the Summer School • Energy Digitalization: Economic and Regulatory Dynamics, and Data Management • Control for Inverter-Based Resources in Energy Systems • Real-Time Simulation, Estimation, and Reliability in Power Systems • Cyber Security and Data Privacy in Energy Systems
Type: Local Training Course
Date: 2024-10-11
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Hardware in the Loop for Renewable systems with SoC platforms (HILRES'24)Cheikh Elkebir Sidi Lekhel (ESR09)ESR09 attended the HILRES’24 training course held at CY Cergy-Paris University on the 27th, 28th, and 29th of November 2024. Organized under the IEEE-IES framework, the event focused on advanced topics in Hardware-in-the-Loop (HIL) and Real-Time Simulation. |
DC grid interface converter based on Three-phase isolated matrix topology with phase-shift modulationPietro Emiliani (ESR10)Conference paper presented at PEDG2022 |
Reactive Power Control for Bidirectional Isolated High-Frequency Link ConverterPietro Emiliani (ESR10)Conference paper presented at SPEEDAM2022 |
Comparative Evaluation of Isolated dc-dc Converters for Low Power ApplicationsMohammadreza Azizi (ESR05)Isolated dc-dc converters are particularly important for utilizing renewable energy. These converters are used for direct connection to the dc microgrid or as voltage boosters for on/off-grid ac applications. This article examines and evaluates five popular types of isolated dc-dc converters for low-power applications. In this study, by examining the performance of converters, the general equations governing these converters have been extracted. The converter components are then designed for a low-power application. Using simulations in Simulink/MATLAB, these converters have been evaluated and compared from different perspectives. Published in: 2022 IEEE 20th International Power Electronics and Motion Control Conference (PEMC) held at Transilvania University in Brasov, Romania. DOI: 10.1109/PEMC51159.2022.9962944 |
Feature of Solar Radiation Forecast Services Use for Solar PlantsMykola Lukianov (ESR06)The main purpose of the study is the review common cloudiness forecast services, uncertainty interval calculation of solar radiation for these services based on comparing with real solar radiation, estimating the opportunity of combining forecast data from several sources to minimize error and analysing the profit from the power plant using forecast services. I. Verbytskyi, M. Lukianov and R. Strzelecki, "Feature of Solar Radiation Forecast Services Use for Solar Plants," 2022 IEEE 8th International Conference on Energy Smart Systems (ESS), Kyiv, Ukraine, 2022, pp. 108-111, doi: 10.1109/ESS57819.2022.9969258. |
Black Start and Fault Tolerant Operation of Isolated Matrix Converter for dc MicrogridsPietro Emiliani (ESR10)Conference Paper presented at IECON2022 |
Digital Control of PFC Rectifier with Combined Feedforward and PI RegulatorPietro Emiliani (ESR10)Conference paper presented at IECON2022 |
Comparison of Four-Switch Buck-Boost and Dual Active Bridge Converter for DC Microgrid ApplicationsGabriele Arena (ESR08)Abstract: Attention to DC Microgrids is recently increasing, due to the expansion of DC components, such as renewable energy sources (RESs), energy storage systems (ESSs), and DC loads. There is a large number of scientific publications on different converter topologies, but only a few of them addresses a direct comparison of different DC/DC converter solution for Microgrid applications. This work presents a comparison between Four-Switch Buck-Boost and Dual Active Bridge Converters in terms of applicability to DC Microgrids, considering efficiency and short circuit behavior. |
Accuracy Analysis of Dual Active Bridge Simulations under Different Integration MethodsGabriele Arena (ESR08)Abstract: One of the biggest challenge in the power electronics field is the simulation of power converters. Computer simulations and real-time simulations are really important in this field because they allow to save money during the prototyping stage and to make the entire process more efficient by predicting possible malfunctions already in the design stage. This paper introduces the impact of using different integration methods for solving the differential equations of power converters on the accuracy of the simulation. In particular, the paper focus on one of the most adopted DC-DC converter topology for automotive and microgrid applications, which is the Dual Active Bridge. |
Performance Evaluation of a Three-Phase PV Power Plant under Unbalanced Conditions with Islanding Detection Reliability TestAnas Abdullah Alvi (ESR03)The use of renewable energy is increasing ever so highly during this modern age of technology. The use of wind, solar and hydro energy is rising rapidly in the world due to the less emissions of harmful gases in the atmosphere. Since the energy produced from these sources like wind and solar energy is increasing a lot, the use of grid connected inverters is also expanding. Deep analysis of these inverters’ operation is important when working in non-ideal situations. The main aim of this paper is to analyze the operation of a three-phase photovoltaic power plant (rated at 250 kW) supplying power to both three-phase and single-phase loads. The analysis covers both, connected and disconnected modes and also includes the performance of a basic islanding detection method considering voltage and frequency deviation of the phase locked loop (PLL) at the Point of Common Coupling (PCC) and the effect on the whole system considering unbalanced situations with different values of irradiances is observed. The novelty of this paper is to identify a case in which the islanding detection fails due to the connection of a single-phase load in the point of low voltage. |
Identification of static and dynamic parameters of PV models through multi-objective optimizationLuis Enrique Garcia Marrero (ESR11)The accuracy of photovoltaic models used to describe the characteristics of photovoltaic panels is crucial to evaluate the performance and to ensure safety, cost-effectiveness and compliance of photovoltaic systems. In particular, when the parameters for static and dynamic models are optimized independently, it has been shown that they might be not consistent across different environmental conditions. By exploiting the dependency of common parameters between the two models, the fitting problem is transformed into a multi-objective optimization problem, which is solved using evolutionary algorithms. The results showed that selecting a tradeoff solution from the Pareto front obtained, leads to a more consistent set of parameters for each environmental condition analyzed. |
Bidirectional EV Charger Integration into LV DC Traction GridMykola Lukianov (ESR06)Conference paper presented at IEEE CPE-POWERENG 2023 |
Back-to-Back Energy Router Based on Common-Ground InvertersMohammadreza Azizi (ESR05)This paper proposes an energy router based on a back-to-back structure with common-ground inverters. Connecting the neutral wire of the ac system to the negative port of the dc link eliminates leakage currents and ensures safety. The proposed energy router uses two common-ground inverters. Each inverter has five switches and has the ability to increase/decrease the voltage and operate in both directions. The operation mode of the common-ground inverter has been investigated and the simulation results using PLECS confirm the accuracy of the overall structure and benefits compared to classical H-bridge inverter. |
Challenges in photovoltaic parameter identification under mismatching conditionsLuis Enrique Garcia Marrero (ESR11)When connecting a few solar cells in series to create a photovoltaic (PV) module, even the smallest discrepancies between them are enough to create mismatch losses. Sometimes this mismatch is mainly due to the non–uniformity of the operating conditions associated with variations in irradiance or cell temperature. However, even under uniform conditions, the unavoidable dispersion of the intrinsic parameters of the cells, due to degradation and aging effects, could be a cause of mismatch because each cell, sharing the same value of current, will be polarized at a slightly different voltage. For accounting for the presence of mismatch in a series of PV cells a Double - Single Diode Model (D-SDM) is introduced in this paper. The parameters between the resulting two SDMs circuits were related to obtaining reliable and coherent characterization for different operating conditions. A robust procedure is developed for estimating its parameters and evolutionary algorithms are employed to solve the optimization problem. The proposed methodology was also validated using experimental data from a single cell of the same type as the module. |
Dynamic Modeling of Si-based Photovoltaic Modules using Impedance Spectroscopy TechniqueLuis Enrique Garcia Marrero (ESR11)In a scenario where the deployment of photovoltaic (PV) systems is increasing, the characterization and the monitoring of the state of health are pivotal. To this aim, Impedance Spectroscopy (IS) provides useful information about the dynamics of PV generators. In this work, an equivalent electric ac model for the characterization of PV modules is discussed. The model is applied to experimental spectra measured on a 52Wp c-Si based PV module in outdoor conditions. The fitting problem is solved by means of two different approaches, one based on the analytic solution of the model equations which employs few points of the experimental spectrum and the other based on an optimization algorithm, requiring the whole set of frequency points. The parameters’ values obtained from both approaches are commented, providing useful information on the behavior of the PV module under test. |
Converter Averaging Approach for Modeling a Residential Supply SubsystemLuis Ignacio Martínez Caballero (ESR02)Conference paper presented at CPE-POWERENG 2023 |
Control Strategy of Hybrid Energy Storage System for High-Dynamic Load ChangesLuis Ignacio Martínez Caballero (ESR02)Paper submitted at CPE-POWERENG 2023 |
An Improved Three-Phase Transformerless Neutral Point Clamped Inverter Topology for Common Mode Voltage ReductionJamil Hassan (ESR01)Transformerless photovoltaic (PV) inverters are more effective, lighter in weight, and less expensive than transformer-based topologies. However, a leakage current (iLeakage) is produced when transformers are removed due to the direct connection between the PV panel and the grid. This current reduces the life of the insulation, causes safety problems, and increases the harmonic distortion in the grid current. To overcome these issues, an improved three-phase transformerless neutral point clamped (NPC) topology is proposed by employing two additional switches on the primary side of a traditional NPC inverter. This arrangement reduces the i Leakage significantly and improves the harmonic behavior of the grid current by operating the additional switches in zero switching states. Furthermore, when compared to a conventional H8 inverter, its multilevel capability reduces voltage stress on semiconductor devices. Finally, the proposed topology is validated with the help of the Simulink model in MATLAB by comparing it to a traditional three-phase H8 inverter, considering iLeakage, common-mode voltage (CMV), and the grid current total harmonic distortions (THD). |
Modular Multilevel Converters Enabling Multibus DC DistributionMahyar Hassanifar (ESR07)The modular multilevel converter (MMC) is a promising topology for enabling hybrid grids, which includes different medium- and low-voltage (MV and LV) ac and dc grids. Owing to its capability to break dc current and work in buck mode, especially, MMCs have been widely studied for MVdc applications in ac-dc hybrid grids. It has been adopted as a frontend bidirectional ac-dc converter or a dc-dc converter employing medium frequency transformers to enable ultra-fast charging stations. Furthermore, MMC can provide different levels of LVdc by expanding the topology with an additional converter, which can help to realize a multibus dc distribution grid. Finally, this property can be used to realize a solid-state transformer (SST) for hybrid grids. However, it is required to identify and characterize the merits and demerits of various MMC structures available to form multibus dc distribution systems. Therefore, in this paper, MMC-based converters proposed in the literature are classified according to the ac-dc and dc-dc conversions. In addition, expected challenges and further possibilities in using them as a multibus dc enabler are also discussed in this paper. |
DC Fast Charging of Electric Vehicles: a Review on Architecture and Power Conversion TechnologyGabriele Arena (ESR08)Abstract: Increasing efforts have been made over the years in order to make a green energy transition possible and widespread of electric vehicles (EVs) is expected to play a key role in this regard. However, EVs require a distributed and reliable infrastructure of charging stations in order to get popularity among customers. Moreover, charging time of EVs is a crucial point that companies and researchers need to face in order to guarantee the same reliability of internal combustion engine vehicles (ICEVs). For these reasons, this paper aims to review architectures and power converters typically adopted in DC fast charging stations. |
Predictive Control for Isolated Matrix Rectifier Without Current Distortion at Sector BoundaryGabriele Arena (ESR08)Abstract: Three phase active rectifiers are needed to supply dc loads from the ac distribution grid without introducing large distortions on the ac grid. Galvanic isolation is a requirement for many applications due to safety concerns. High frequency link power conversion topologies, based on indirect matrix converters, are an emerging solution for such applications. In this paper a predictive digital control is developed for an isolated three phase ac/dc matrix converter by combining a deadbeat controller and space vector modulation. This approach simplifies the controller design and allows for full-range soft-switching with sinusoidal input currents. Due to the discrete operating sectors of high frequency link topologies, an additional modulation mode is introduced near sector boundaries, reducing the distortion caused by sector changes. The proposed deadbeat controller is validated with PSIM simulations. |
Three-Phase Four Wire High-Frequency Link Converter for Residential DC GridsGabriele Arena (ESR08)Abstract: There is increasing penetration of dc native renewable technologies, such as batteries and photovoltaics in the distribution grid. These renewable technologies can be interconnected with dc microgrids, which in turn often have a bidirectional connection with the ac distribution grid to enable energy exchange. For safety reasons, this connection is often galvanically isolated with a transformer. This paper presents a single stage high frequency link converter, based on an indirect matrix converter. A three leg four wire configuration is proposed to be able to operate in unbalanced conditions and provide various ancillary grid services. A digital controller is developed to control the grid currents and eliminate distortion at the zero crossing of the matrix converter. The results are verified with a PSIM model. |
A Comparative Study of Three-Phase Inverter Topologies for Common Mode Voltage Reduction in Photovoltaic ApplicationsJamil Hassan (ESR01)The popularity of photovoltaic (PV) systems has increased as the demand for renewable energy sources has risen in recent years. The inverter is an important component and has a significant impact on the overall performance of a PV system. Therefore, its topology must be chosen carefully based on the application. This paper presents a study and comparison of different inverter topologies for PV applications. The paper begins by discussing the traditional three-phase H6 inverter topology for PV systems and then reviews various inverter topologies derived from this structure for leakage current reduction. Three topologies are chosen and compared their potential for PV applications considering leakage currents and total harmonic distortions using the MATLAB/Simulink simulation model. |
Semiconductor Devices Condition Monitoring Using Harmonics in Inverter Control VariablesShuyu Ou (ESR04)The health status of power semiconductor devices in power converters is important but difficult to monitor. This paper analyzes the relationship between harmonics in inverter control variables and a health precursor (the on-state voltage V on of power semiconductor devices). Based on the analysis, harmonics can estimate V on without adding extra sensing circuits. The method is validated through simulations. |
A Data-Driven Condition Monitoring Method for Capacitor in Modular Multilevel Converter (MMC)Shuyu Ou (ESR04)Abstract The modular multilevel converter (MMC) is a topology that consists of a high number of capacitors, and degradation of capacitors can lead to converter malfunction, limiting the overall system lifetime. Condition monitoring methods can be applied to assess the health status of capacitors and realize predictive maintenance to improve reliability. Current research works for condition monitoring of capacitors in an MMC mainly monitor either capacitance or equivalent series resistance (ESR), while these two health indicators can shift at different speeds and lead to different end-of-life times. Hence, monitoring only one of these parameters may lead to unreliable health status evaluation. This paper proposes a data-driven method to estimate capacitance and ESR at the same time, in which particle swarm optimization (PSO) is leveraged to update the obtained estimations. Then, the results of the estimations are used to predict the sub-module voltage, which is based on a capacitor voltage equation. Furthermore, minimizing the mean square error between the predicted and actual measured voltage makes the estimations closer to the actual values. The effectiveness and feasibility of the proposed method are validated through simulations and experiments. |
Advancements in Photovoltaic Research: Electro-Impedance Spectroscopy for PV Cell CharacterizationLuis Enrique Garcia Marrero (ESR11)This article presents a method for characterizing the dynamic behavior of photovoltaic (PV) cells using the Electro-Impedance Spectroscopy (EIS) technique. High-precision laboratory equipment has been used to measure a single PV cell, capturing impedance (Z LB) and voltage-current (I - V ) curve characteristics. We propose a model incorporating variable capacitance and conductance behavior for describing diode impedance dynamics. The experimental IV curve and impedance measurements are used as the reference for model parameters fitting through an evolutionary algorithm. Exploiting data from a single spectral measurement at a specific operating point, the methodology enables the prediction of the IV curve and spectral impedance plot at any operating point, as long as the irradiance conditions remain constant. The experimentation in a PV cell demonstrates a strong match between the obtained real data and the mathematical model. However, it is important to note that these findings are based on controlled simulated environmental conditions in a single cell. Further testing on PV panels is required to reproduce conditions such as mismatch or partial shadowing in order to stress and test the proposed model. |
Impedance Spectroscopy for partial shading detection on series-connected PV panelsLuis Enrique Garcia Marrero (ESR11)This work investigates an improved method for detecting and simulating the effect of partial shading on photovoltaic (PV) panels by combining experimental and simulation procedures. The method entails measuring current-voltage (IV) curves and impedance spectra for two Photovoltaic (PV) panels under outdoor conditions. The shade is then recreated in one panel, and measurements are repeated to generate a dataset for adjusting a Constant Phase Element (CPE). In addition, the single-diode model (SDM) is tested using the SPICE environment for further validation. Experiments are repeated at different irradiances and operation points to fully understand PV panel performance in diverse environments. The paper focuses on the experimental outcomes. This study examines tuning a CPE model based on experimental data and using the single-diode model in SPICE simulations. The study's comprehensiveness is demonstrated by presenting data for various irradiances and operating points. The improved CPE model's reliability and precision, as well as validation of the single diode model in SPICE, are emphasized. The findings from the experiments contribute to better comprehension of PV panel dynamics in non-uniform scenarios. The importance of reproducing these results in simulation for engineering applications is emphasized, providing the path for future advances in PV panel design and optimization based on spectrum measurements. |
Multi-Objective Energy Management of Smart Buildings Through a Bilevel Optimization ApproachSaeed Akbari (ESR12)This paper introduces an optimization-based model developed to manage energy flow within smart buildings while facilitating energy exchange with the grid through a bi-level framework. The primary objective of this model is to minimize electricity bills while improving the peak-to-valley ratio of power exchange profiles with the grid, concerning system constraints and users' comfort. To achieve this, an energy storage system is incorporated to handle peak-shaving and valley-filling applications. Notably, the energy storage system operates as the follower of the building energy management system, focusing on improving the energy exchange profile. Simulation results demonstrate the effectiveness of this energy management strategy in enhancing techno-economic metrics simultaneously. |
Dc Leakage Current in Isolated Grid-Connected dc Nanogrid-Origins and Elimination MethodsMohammadreza Azizi (ESR05)The LVdc system is a relatively new trend in the distribution sector, which seems to grow widely in the near future due to its promising advantages. In this context, LVdc protection and grounding are challenging issues. Although the galvanically isolated connection mode of dc nanogrid to the ac grid has high reliability, the leakage current can still be injected into the ac grid through the interwinding capacitors and the insulation resistance between the primary and secondary windings of the transformer. The way of grounding the dc nanogrid can also be a determining factor in the leakage current and its dc components. This study deals with the leakage current in the galvanically isolated dc nanogrid. Then, it examines the dc leakage current and its relationship with the dc nanogrid grounding and finally provides solutions to remove the dc components in the leakage current. |
An Economical Optimization for the Participation of a Residential Microgrid in Flexibility Markets Providing Ancillary ServicesAnas Abdullah Alvi (ESR03)The growing number of renewable energies based distributed energy resources and new loads such as electric vehicles are creating uncertainty and instability in the grid and thus increasing the need to provide ancillary services and other flexibility resources. This paper deals with an economical optimization of power reservation of energy storage systems in a residential microgrid to provide ancillary services and thus participating in flexibility markets by receiving economic incentives. The study proposes an energy management system for a residential microgrid that includes household loads, photovoltaic generation, energy storage systems and electric vehicles. The economic objective of reducing electricity bill and the technical goal of providing ancillary services by reserving a fixed power capacity of the energy storage systems along with including grid congestion constraint are achieved by designing and testing a genetic algorithm with suitable parameters to define new set-points of operation for the energy storage systems and the charging/discharging of electric vehicles. |
Energy Communities in the EU: Analysis of ownership models and funding mechanismsKonstantinos Pantazis (ESR15)Energy Communities (ECs) have gained much attention in academia and policy as they embody the active participation of citizens in the energy transition. However, different actors can participate in ECs, and various ownership models and legal forms can emerge based on their relationships. For instance, some are limited liability companies, or cooperatives, or free associations with various private and public actors as members or initiators of the EC. The ownership model has an impact on the ways that ECs can raise capital and fund their activities. For example, some communities are based on equity capital, whereas others have better access to debt capital. However, there is no academic literature that examines the relationship between the ownership model of ECs and the funding mechanisms they use. Therefore, the current study aims to categorize the ECs that exist in the EU based on their ownership model and to examine the relationship, between ownership models and the funding mechanisms used to finance energy generation plants. Finally, this study explores the barriers ECs face in order to raise capital and finance their activities. The ownership model consists of five elements, (a) the membership, (b) the governance structure, (c) the purpose of the organization, (d) the local distribution of benefits (e) the initiators of ECs. To achieve the above research objective, a survey, using a self-completion questionnaire, was conducted and distributed to ECs in the EU. No differences were found between the ECs in terms of governance, local distribution of benefits, and the purpose of the organization. However, the ECs differ significantly from each other in terms of the members and initiators of the ECs. Based on these two dimensions, eight (8) different categories were identified. Furthermore, each of these categories uses different funding mechanisms to raise funds and finance their projects. Finally, it appears that the size of the investment and the size of the EC, in terms of the number of members, affect the financing mechanism used by ECs. |
Study of Battery Energy Storage Operation in Droop-Controlled Residential DC NanogridSayeed Hasan (ESR10)Abstract: Conventional AC systems offer a straightforward, adaptable, and reliable electrification solution for residential buildings. However, this simplicity has several drawbacks when utilizing renewables, such as decreased efficiency due to additional conversion stages, load imbalance in multiphase systems, harmonics, and improper energy balance. A DC-based approach could be used instead of the AC in residential nanogrids (NGs). For a residential NG, DC systems can eliminate those DC-AC conversion stages by only relying on one grid-side active front-end converter. Additionally, using DC droop control, the stable operation of a DC NG can be achieved without extra communication between converters sharing the DC bus. The paper focuses on simulating the operation of a droop-controlled residential DC NG for the case of maximum self-consumption and the resulting battery degradation. The simulation used a J-minute temporal average, actual generation, and consumption data from an Estonian dwelling. In addition, the simulation considers the economic aspects of the system and battery reliability assessment using simulated data. |
A Current Control Method for an Interleaved Boost Converter Under CCM/DCM Operation in a PV SystemLuis Ignacio Martínez Caballero (ESR02)DC-DC boost converters are widely adopted in power conditioning systems for renewable energy sources (RESs) and, due to unidirectional power transfer, are subject to operation in either continuous conduction mode (CCM) or discontinuous conduction mode (DCM). Current controllers that ensure operation in both modes have been developed, however, most of the solutions presented in the literature are developed for power-factor (PFC) correction rectifiers, limiting their application to other systems. In a two-stage photovoltaic (PV) generation system, the boost converter operates in a wide range of input voltages, resulting in DCM under low irradiance conditions or during system startup. This work presents an average current estimation method that provides similar performance to the current reference tracking regardless of the operation mode. The current controller has been designed based on the large signal averaged model which accounts for both operation modes. Moreover, a correction factor is derived to generate the correct duty cycle based on the average voltage of the switching leg. Simulation studies are conducted to evaluate the performance of the proposed method, the operation for the switching and averaged model is shown, and the transition between the two modes is demonstrated. |
Fault Tolerant Control for Medium Voltage Hybrid MMC With Cold Reserve SubmodulesMahyar Hassanifar (ESR07)The hybrid modular multilevel converter (HMMC), which consists of half-and full-bridge sub modules (SMs), offers critical advantages in handling overmodulation conditions and blocking dc fault current compared to half-bridge MMC. The high number of SMs poses a threat to the proper operation of the HMMC after an SM failure. To ensure the reliability of HMMC, the use of redundant SMs is pivotal, particularly in medium-voltage applications where the number of SMs is comparatively lower than in high-voltage ones. The redundant SM can be used as a cold reserve SM, referring to the condition that the redundant SM is not being used in the normal condition and inserted after SM failure, which prevents an increase in MMC losses and components thermal stress. This work proposes a sorting method for the seamless and smooth insertion of the cold reserve SM in the event of SM failure, as a replacement for faulty SM. The main goal is to avoid the inrush current and high stress on the capacitor during the insertion of cold reserve SM and achieve a controlled charging process of the capacitor in the inserted SM. Finally, the feasibility and effectiveness of the suggested method are validated through comprehensive simulation studies. |
Modified Sorting Algorithm for Fault- Tolerant Operation of Hybrid MMC With Hot Reserve SubmodulesMahyar Hassanifar (ESR07)The hybrid modular multilevel converter (HMMC) is formed of a combination of half- and full-bridge submodules. HMMC offers advantages in working under overmodulation conditions and effectively blocking the dc fault current with a reduced number of semiconductor switches compared to FB-based MMC, which makes it a fitting option for high and medium-voltage applications. While the modular nature of the MMC is considered a key strength, a high number of power switches raises a potential reliability concern in the event of sub-module (SM) failure. Hence, the implementation of fault-tolerant strategies is critical to ensure the uninterrupted operation of the HMMC. This study aims to develop a fault-tolerant technique through hot reserve redundant SMs by using a modified sorting algorithm. The sorting algorithm is adopted to ensure the correct operation of HMMC during fault occurrence. Also, this work introduces a new control on the insertion index to operate in overmodulation operating mode with reduced dc-link voltage. Finally, the feasibility and availability of the modified sorting method for using hot reserve SMs in HMMC are verified through the EMT simulations in MATLAB\Simulink environment. |
Assessment of Mixed Energy Storage System Considering High Spatial Resolution Data from a Real PV InstallationSayeed Hasan (ESR10)Abstract: This paper focuses on improving instability issues in typical residential PV micro installation operation. Based on the high-resolution long-term recording of the power fluctuation in residential photovoltaic installations located in Tallinn, Estonia, different instability problems are identified and addressed. A mixed energy storage system (ESS) was considered for rapid and effective compensation of the detected fluctuations. A hybrid supercapacitor and battery based system was proposed to mitigate the actual problems in PV generation and balance the system operation. A 32 Wh supercapacitor bank coupled to the DC link of the PV inverter was proposed to mitigate the short-term and long-term power fluctuations on the generation side. Peaks and dips in the consumption and generation were identified using the Z-score-based peak detection method. The experimental results from different ESS sizes were compared and discussed. Moreover, several instances of generation fluctuations were mitigated by utilizing the supercapacitor bank. |
Implementation Issues of Droop Controlled DC Nanogrids: State of Charge Management of Battery Energy Storage and Impact of Sensor Gain ToleranceSayeed Hasan (ESR10)Abstract: DC nanogrids are becoming more prevalent for efficient residential electrification in both rural and urban areas. Droop-controlled DC nanogrids are a viable substitute for conventional AC nanogrids owing to their advantages, such as no need for synchronization, reduced material usage, higher efficiency, and flexible operation. However, adopting fixed droop curves in a DC nanogrid has some limitations related to the practical implementation of measurements. This paper shows how these issues affect the state of charge management and energy flow control of a battery energy storage system (BESS). A framework for energy flow and BESS state of charge (SOC) management by means of online modification of droop curves is implemented based on the measured DC bus voltage and estimated SOC values. Moreover, the paper analyzes how tolerance of the embedded measurement system influences DC nanogrid operation and provides recommendations for its design. |
Power Converter Solutions for Industrial PV Applications—A ReviewMykola Lukianov (ESR06)The paper conducts a comparison of different topologies on power converters based on two parameters that describe their cost and power loss for various PV applications. For a straightforward study, these parameters are represented using the gain factor, which allows for an accurate comparison of the efficiency of various types of converters. Energies 15, no. 9: 3295, doi: 10.3390/en15093295 |
A Genetic Algorithm for Residential Virtual Power Plants with Electric Vehicle Management Providing Ancillary ServicesAnas Abdullah Alvi (ESR03)Virtual power plants are a useful tool for integrating distributed resources such as renewable generation, electric vehicles, manageable loads, and energy storage systems under a coordinated management system to obtain economic advantages and provide ancillary services to the grid. This study proposes a management system for a residential virtual power plant that includes household loads, photovoltaic generation, energy storage systems, and electric vehicles. With the proposed management system, the virtual power plant is economically optimized (as in commercial virtual power plants) while providing ancillary services (as in technical virtual power plants) to the distribution grid. A genetic algorithm with appropriate constraints is designed and tested to manage the energy storage system and the charge/discharge of electric vehicles, with several economic and technical objectives. Single-objective optimization techniques are compared to multi-objective ones to show that the former perform better in the studied scenarios. A deterministic gradient-based optimization method is also used to validate the performance of the genetic algorithm. The results show that these technical targets (usually reserved for larger virtual power plants) and economic targets can be easily managed in restricted-sized virtual power plants. |
Power converter interface for urban DC traction substations - solutions and functionalityMykola Lukianov (ESR06)This paper focuses on extending an urban DC traction substation functionality by means of an additional power converter interface (PCI). In particular, by enabling bidirectional energy exchange between LV DC traction grid, AC grid and V2G chargers. Among other things, the presented material compares general attributes of the most promising DC/DC converters that can be used in a PCI, meet the requirements of galvanic isolation and can operate in a wide voltage range. Based on the literature, the application suitability of typical PCI structures and isolated DC/DC converters was made. In addition, the principles of power flow in the power converter interface that connects an AC grid, DC traction grid, V2G chargers and PV source are discussed.
Type: Journal Publication
Date: 2023-11-01
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Grounding and Isolation Requirements in DC Microgrids: Overview and Critical AnalysisMohammadreza Azizi (ESR05)DC microgrids, along with existing AC grids, are a future trend in energy distribution systems. At the same time, many related issues are still undefined and unsolved. In particular, uncertainty prevails in isolation requirements between AC grids and novel microgrids as well as in the grounding approaches. This paper presents a critical technical analysis and an overview of possible grounding approaches in DC systems and the feasibility of avoiding isolation between AC and DC grids.
Type: Journal Publication
Date: 2023-11-24
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Comparison of Energy Storage Management Techniques for a Grid-Connected PV- and Battery-Supplied Residential SystemLuis Ignacio Martínez Caballero (ESR02)Open access publication accepted in the journal Electronics |
Cooperative stochastic energy management of networked energy hubs considering environmental perspectivesSaeed Akbari (ESR12)Energy hubs (EHs) aim to increase the flexibility of energy systems by adopting different energy carriers and sources. This paper presents a cooperative stochastic framework for managing networked EHs (NEHs) from an economic-environmental perspective. Scenario preparation techniques, such as Monte Carlo simulation (MCS) and the k-means clustering algorithm, are used to develop scenarios for different sources of uncertainty. Furthermore, the Shapley value is used to allocate coalition gains among NEHs based on their contributions and performance. To distinguish the proposed model from existing literature, several case studies have been conducted to assess its effectiveness. Conducted simulations show that through cooperation, the total cost of EHs and CO2 emissions is reduced by approximately 3 % and 1.8 %, respectively. Moreover, the performed sensitivity analyses indicate the robustness and reliability of the model against input parameters. |
The potential of residential load flexibility: An approach for assessing operational flexibilitySaeed Akbari (ESR12)The potential of residential load flexibility: An approach for assessing operational flexibility |
Traditional and Hybrid Topologies for Single-/Three-Phase Transformerless Multilevel InvertersAyesha Aslam (ESR01)With increasing interest in integrating solar power into the utility grid, multilevel inverters are gaining much more attention for medium- and high-power applications due to their high-quality waveform, low voltage stress across active components, and low total harmonic distortion in output voltage. However, to achieve these benefits, a large number of active and passive components are required. A transformer is also required to provide galvanic isolation, which increases its size and weight and reduces its power density and efficiency. In order to overcome the disadvantages posed by transformer-based inverters, research is being conducted on the transformerless topology of multilevel inverters. The first aim of this review article is to summarize traditional transformerless multilevel inverters (TMLIs) considering both single- and three-phase topologies. Secondly, the main aim of this article is to provide a detailed overview of the hybrid topologies of TMLIs that employ fewer components for photovoltaic applications. In addition, this study compares traditional and hybrid single-/three-phase topologies in terms of component count and performance factors, which will be useful to researchers. |
Online real-time robust framework for non-intrusive load monitoring in constrained edge devicesLuis Enrique Garcia Marrero (ESR11)Real-time information on detailed power consumption can motivate users to make informed decisions to reduce their energy bills. In that sense, Non-Intrusive Load Monitoring (NILM) emerges as a cost-effective technique to achieve the previously mentioned benefits. This paper presents an online real-time robust NILM framework that only requires the aggregated active power, operates by updating the appliance’s state probabilities sequentially, and uses this information to predict the power consumption of each monitored appliance. The framework primarily focuses on the seamless integration and practical deployment of a real-time NILM algorithm, operating at frequencies around 1 Hz, on constrained edge devices. Starting with detecting edges and the base load in real-time, the appliance’s state probabilities are updated considering the possible presence of unknown loads. The power consumption of each appliance is then estimated by employing a modified Population-Based Incremental Learning algorithm (PBIL). Experiments on two publicly available datasets against state-of-the-art methods demonstrated its accuracy and robustness in the presence of unknown appliances. The real-time capabilities of the framework were verified through integration in a Home Automation framework running in a constrained edge device. |
Influence of the temperature on the intrinsic parameters of thin-film photovoltaic modulesLuis Enrique Garcia Marrero (ESR11)The electrical parameters, the ideality diode factor and the parasitic resistances of a photovoltaic module can be estimated from its current–voltage (I–V) curve. However, there are only very few studies focused on thin-film devices, that could have a thermal behavior different from crystalline silicon technologies. This study analyzes the variation of these parameters from a set of current–voltage curves of several commercial modules from different technologies: single-crystalline silicon (sc-Si), multi-crystalline silicon (mc-Si), amorphous silicon (a-Si), tandem of micro-crystalline silicon and amorphous silicon (a-Si/c-Si), tandem of cadmium selenide and cadmium telluride (CdS/CdTe), and copper indium selenide (CIS). Most of the modules present a positive value for the current thermal coefficient, but the voltage and power temperature coefficients are negative in all the cases. With respect the series resistance, it is significantly higher for the thin-film modules than for the crystalline silicon ones. Moreover, the thermal coefficient of the series resistance varies depending on the technology. Regarding the shunt resistance, it seems to be insensitive with respect the temperature for a small range. Finally, the diode ideality factor seems to be constant for crystalline silicon whereas it depends on the temperature for thin-film. |
Best Student Contest Award of 2022 AEIT International Annual ConferenceGabriele Arena (ESR08)This award has been given for the best student paper of 2022 AEIT International Annual Conference in Rome. The title of the paper is "Accuracy Analysis of Dual Active Bridge Simulations under Different Integration Methods". |
Best Paper Award of the 14th Advanced Doctoral Conference On Computing, Electrical And Industrial Systems (DoCEIS 2023)S.M. Masum Ahmed (ESR14)This award is presented to "S.M. Masum Ahmed, Edoardo Croci, Annamaria Bagaini " for the paper "A Critical Review of District Heating and District Cooling Socioeconomic and Environmental Benefits" in the field of "Developments in Electronics, Communication and Energy", presented at the Doctoral Conference On Computing, Electrical And Industrial Systems (DoCEIS 2023) held in Monte da Caparica, Lisbon, from July 5th to 7th, 2023.
Type: Award
Date: 2023-07-07
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Best Poster Award in Research Day of Aalborg University Energy DepartmentShuyu Ou (ESR04)The award is given for the best PhD poster at AAU Energy Research Day 2024.
Type: Award
Date: 2024-04-23
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IES Student and Young Professional Paper Assistance awardMohammadreza Azizi (ESR05)The Student & Young Professionals (S&YP) Activity Committee of the Industrial Electronics Society (IES) is continuously implementing a paper assistance program (IES-SYPA) – competition-based financial support for the IES S&YP members to attend IES Majority Sponsored Conferences. |
IEEE IES Student and Young Professionals Paper AssistanceSayeed Hasan (ESR10)ESR10 won IEEE IES SYPA travel allowance for CPE-POWERENG 2024 by becoming one of the winner of IEEE IES 3-minute video competition.
Type: Award
Date: 2024-06-26
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Most Active Participant in the "Power Electronic Converters and Applications: Part 2 " - RTUCON2024Sayeed Hasan (ESR10)ESR10 won the most active participant in Power Electronic Converters and Applications (2nd session) in the 65th International Scientific Conference on Power and Electrical Engineering (RTUCON 2024).
Type: Award
Date: 2024-10-11
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Presentation "DC Grid Interface Converter Based on Three-Phase Isolated Matrix Topology with Phase- Shift Modulation"Pietro Emiliani (ESR10)Presentation at the 21st International Symposium “TOPICAL PROBLEMS IN THE FIELD OF ELECTRICAL AND POWER ENGINEERING” and “Doctoral School of Energy and Geotechnology III.” The total number of event attendees was around 80. |
Hybrid distribution transformer with MV side control and DC bus for connecting an EV chargerMykola Lukianov (ESR06)This paper discusses a hybrid distribution transformer (HDT) with medium-voltage side control as an alternative to typical low-voltage sidecontrol. The HDT system consists of a network transformer anda converter that regulates thevoltage to ensure output voltage stability. The advantages of HDT with a MV side converter are smaller semiconductor switch currents and the absence of a neutral wire. The use of a three-level "back-to-back" NPC converter with a DC link is under consideration, allowing the connectionof additional DC loads/sources (e.g., V2G chargers). The parameters of the 630kVA 15/0.4kV HDT were estimated, the settingsof the basic control system wereselected, and the most important simulation results were presented. Mykola LUKIANOV, Wojciech MATELSKI, Antoni KRAHEL, Ievgen VERBYTSKYI, Ryszard STRZELECKI, “Hybrid distribution transformer with MV side control and DC bus for connecting an EV charger”, The 15th Conference Control in Power Electronics and Electric Drives - "SENE 2022“, November 23-25th 2022. |
LV DC traction substation with connected bidirectional EV chargers and improved functionalityMykola Lukianov (ESR06)Presentation at XI Technical-Scientific Conference – I-MITEL-2023 in Sulęcin, Poland |
On-line diagnosis and optimization of Energy Management Systems for Smart BuildingsLuis Enrique Garcia Marrero (ESR11)Poster presented at the DoCEIS 2023 conference, to present, promote, and discuss the main ideas of the project plan and the initial results.
Type: Dissemination Activity
Date: 2023-07-06
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European Night of ResearchersAnas Abdullah Alvi (ESR03)Participation in the preparation and execution of the activity-Clean and responsible use of electrical energy carried out within the framework of the European Night of Researchers (Horizon Europe project G9 Missions nº 101061455), coordinated in the UEx by the Scientific Culture Dissemination Service. The activity took place in Badajoz on September 29, 2023. The participation has been for a total of 40 hours. |
Scientific Day of the Doctoral School of Sciences and Engineering (CY Cergy Paris Université)Cheikh Elkebir Sidi Lekhel (ESR09)Poster presentation of the research project, showcasing the project introduction, plan, and initial results.
Type: Dissemination Activity
Date: 2024-01-17
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ECPE workshop on 'RT-HIL Testing of Power Electronics Converter and Drives Systems'Sayeed Hasan (ESR10)From February 7th to 8th, ESR Sayeed Hasan attended the 'ECPE Workshop on RT-HIL Testing of Power Electronics Converter and Drives Systems' organized by the European Center for Power Electronics (ECPE) in Lausanne, Switzerland, in collaboration with École Polytechnique de Lausanne (EPFL). There, he gained firsthand knowledge about different hardware-in-the-loop (HIL) platforms, power HIL (PHIL), and economic and business aspects of HIL and visited the Distributed Electrical Systems Laboratory (DESL) at the EPFL.
Type: Dissemination Activity
Date: 2024-02-07
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SmartGYsum Collaboration Meetup with ESR14 and ESR15Sayeed Hasan (ESR10)On February 9th, ESR10 Sayeed Hasan visited Università Bocconi as part of a research collaboration with ESR14 and ESR15 within the SMARTGYsum project. He represented the Power Electronics Research Group of the Tallinn University of Technology (TalTech), Estonia. He introduced project partners and ESRs to his research work, which contributes to work package 4. The outcomes of his work will be employed for energy management in TalTech’s Residential DC Innovation Hub. Sayeed targets the future direct current (DC) buildings in his research as the enabling technology for zero-emission buildings. In the near future, wide-scale electrification will benefit from the ultimate energy efficiency of DC technologies, which are applicable in all sectors of the economy. His presentation led to a fruitful discussion, including valuable insights on the development of associated business models from Prof. Eduardo Corci, Annamaria Bagaini, and Tania Molteni.
Type: Dissemination Activity
Date: 2024-02-09
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DTU PES Summer School 2024Saeed Akbari (ESR12)I recently attended the DTU PES Summer School 2024, held from May 27th to 31st. This intensive five-day course focused on advanced research topics and innovative methods in power systems. The program featured insightful talks from world-renowned researchers and leading industrial companies in the field, providing a unique opportunity to learn about cutting-edge developments in power systems. During the event, I had the opportunity to present my contributions to the SMARTGYsum project alongside my younger colleagues during the poster presentation session. This experience was particularly valuable as it provided fruitful insights into the future direction of my research. Engaging with other experts and receiving feedback helped refine my approach and highlighted new avenues for exploration in our work. Additionally, participants were offered the chance to earn 2.5 ECTS credits by submitting a comprehensive summary of their learnings post-completion. Overall, this experience has significantly enhanced my expertise in power systems and will positively influence our ongoing projects.
Type: Dissemination Activity
Date: 2024-05-27
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DC PIKNIK/Open Doors DaySayeed Hasan (ESR10)ESR10 actively participated and co-organized the 'DC PIKNIK/Open Doors Day' hosted at Tallinn University of Technology. Furthermore, he showcased his work within the SmartGYsum project, which is going to be an essential element of DC residential microgrids. |
Seconda Conferenza Rete Italiana del FotovoltaicoLuis Enrique Garcia Marrero (ESR11)Poster presentation of the main results obtained in the project
Type: Dissemination Activity
Date: 2024-06-11
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IEEE IES Student Branch Chapters Forum 2024 (IEEE Estonia)Sayeed Hasan (ESR10)On September 25, 2024, the IEEE IES Student Chapter at Tallinn University of Technology (TalTech) hosted the Baltic Sea region's IES SBC Forum. Finnish, Latvian, and one IES student member from the IEEE Italian Section all attended the forum. ESR10 (Chair, IEEE IES TalTech Student Branch) co-hosted the event. The event had 15 doctorate students from several Baltic nations presenting their works.
Type: Dissemination Activity
Date: 2024-09-25
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Electric Power Management and Control in DC Buildings — State-Of-The-Art and Emerging TechnologiesPietro Emiliani (ESR10)Chapter in the book "Power Quality: Infrastructures and Control." PDF cannot be shared publicly. |
A Critical Review of District Heating and District Cooling Socioeconomic and Environmental BenefitsS.M. Masum Ahmed (ESR14)Heating energy demand accounts for almost 50% of global final energy consumption. The cooling demand is also rising, accounting for 16% of the building sector's final electricity consumption. District heating and cooling (DH-DC) can significantly reduce overall energy consumption and CO2 emissions considering the use of green sources and new technologies. Identifying and assessing the benefits generated by DH-DC is crucial for supporting policymakers and driving sustainable financing. This paper aims to identify and categorise DH-DC benefits through a literature review focusing on methods to assess them. In this review, 35 research works have been considered and analysed. Benefits identified in the literature broke down into four categories: benefits for the energy system, end-users, environment, and society. Benefits are well recognised in the literature; however, most studies focused on qualitative analysis with a low impact on DH-DC project assessment. Results will be used to design a new integrated assessment framework.
Type: Book Chapter
Date: 2023-06-25
Available since: 2024-06-27
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An Overview of the Functions of Smart Grids Associated with Virtual Power Plants Including Cybersecurity MeasuresAnas Abdullah Alvi (ESR03)The use of renewable energy is on the rise and is expanding ever so greatly in this modern age of technology. However, it comes with a new set of challenges to properly integrate these renewable energy-based power plants thus forming a virtual power plant safely and reliably into the power grid in which a smart grid plays an effective role. The main focus of this paper is to review the functions a modern-day smart grid plays in the integration of distributed energy resources to the grid to form a virtual power plant including cybersecurity measures. It also addresses a basic example of the detection of a cyber-attack caused into the grid assuming it to be manipulated by a hacker together with a novel solution and later validated by performing simulation. In: Camarinha-Matos, L.M., Ferrada, F. (eds) Technological Innovation for Connected Cyber Physical Spaces. DoCEIS 2023. IFIP Advances in Information and Communication Technology, vol 678. Springer, Cham. |
AN OVERVIEW OF BIDIRECTIONAL EV CHARGERS: EMPOWERING TRACTION GRID-POWERED CHARGERSMykola Lukianov (ESR06)"AN OVERVIEW OF BIDIRECTIONAL EV CHARGERS: EMPOWERING TRACTION GRID-POWERED CHARGERS" - part of the book published by Springer. |
Analyzing Value-Sharing Methods in Energy Communities with Coalitional Game TheorySaeed Akbari (ESR12)Within energy systems, collaboration has recently gained increased attention from academia and industry. However, the success of collaboration requires a fair value-sharing method based on the individual contributions. Coalitional Game Theory (CGT) offers a conceptual framework for analyzing projects where participants cooperate or collaborate to achieve favorable outcomes. The growing importance of collaboration in Energy Communities (ECs) suggests the development of CGT-based frameworks designed to understand the behavior and relationships among diverse players in a variety of operational and planning contexts. This work presents an overview of recent developments in CGT and their application in ECs, starting with a concise theoretical explanation of CGT, focusing value-sharing methods. It then examines recent applications of CGT in addressing operational and planning challenges within ECs. The paper concludes with a brief discussion on limitations, opportunities, and potential paths for further research in this field. |