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). |
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. |
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 |
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 |
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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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. |
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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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. |
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. |