| 1. |
- Archetti, Joao Antonio Guedes, et al.
(författare)
-
Real time validation of a control system for microgrids with distributed generation and storage resources
- 2023
-
Ingår i: Electric power systems research. - : Elsevier. - 0378-7796 .- 1873-2046. ; 223
-
Tidskriftsartikel (refereegranskat)abstract
- Faced with a scenario in which the increase in renewable energy generated near consumer centers can cause problems for the operation of the electrical network, the present work proposes a real-time simulation model for automation and control systems of electrical distribution networks with microgrids, distributed generation, and storage resources. The proposed model consists of a hardware-in-the-loop control with the aid of a simulation tool in conjunction with a Real-Time Digital Simulator (RTDS) and considers the dynamic behavior of switched elements and inverters. A communication platform using TCP/IP protocol between RTDS (power system) and MatLab/Simulink (optimization algorithms) allows the operation of the network in grid-connected and islanded mode, guaranteeing the computational time for experimental implementation. For the first mode, an algorithm is proposed to solve an optimal dispatch energy storage system problem. Second mode, an algorithm is proposed to solve a load shedding problem. The objective is to operate the microgrids optimally and evaluate the performance of a storage system based on real data from the state of Parana, in Brazil. Results show that the optimization algorithms are experimentally applicable, obtaining reasonable computational time to find optimal solutions and an assertive decision-making to meet the objectives. Thus, the proposed framework is a potential tool to validate algorithms for active management of microgrids in real-time simulation.
|
|
| 2. |
- de Barros, Thiago Ribeiro, et al.
(författare)
-
Optimization algorithm associated with local and coordinated controls of distributed energy resources to meet technical and economic criteria
- 2024
-
Ingår i: Electric power systems research. - : Elsevier. - 0378-7796 .- 1873-2046. ; 226
-
Tidskriftsartikel (refereegranskat)abstract
- The present work proposes the development of a simulation platform that integrates the PSCAD software with python language, capable of portraying realistic and dynamic characteristics of the operation of an electrical system with high insertion of DERs. This work considers a scenario with high insertion of alternative sources, which are characterized by intermittent conditions of generation and consumption, therefore causing technical-economic challenges in the operation of the network. In this way, an electrical network will be created with photovoltaic systems, electric vehicles and batterys, in addition to local, coordinated and optimization controls. Local and coordinated controls act on network undervoltage and overvoltage problems. The optimized control, created in Python and based on a Predictive Control Model, determines the optimal operating curve for the batterys, reducing the energy cost of the system, being activated when the network does not present technical problems. Results showed a reduction of more than 16% in the energy cost of the network when enabling the optimized control, keeping the voltage profiles within regulatory limits. Thus, the proposed platform manages to carry out the technical-economic monitoring of the network, becoming a promising tool for the creation of active network management algorithms in dynamic simulations.
|
|
| 3. |
- Archetti, Joao A. G., et al.
(författare)
-
Hardware-in-the-Loop Volt-Watt and Volt-VAr Control for Distribution Systems with High Penetration of Renewables
- 2023
-
Ingår i: Journal of Control Automation and Electrical Systems. - : Springer Nature. - 2195-3880 .- 2195-3899. ; 34:1, s. 177-188
-
Tidskriftsartikel (refereegranskat)abstract
- This work aims to validate in control hardware in the loop (CHIL) simulations new voltage profile control strategies in distribution systems with different levels of photovoltaic penetration. The proposed control is implemented through intelligent inverters with control functions that act through voltage sensitivity. The Volt-VAr (V-V) and Volt-Watt (V-W) functions act in the local voltage control being implemented in a complementary way. The simulations are performed in real time, using the real-time digital simulator. Residential load profiles, solar irradiance and temperature curves are discretized hourly over a daily period, with the intention of making the emulation more realistic. Voltage source converters were implemented in RSCAD software. The contribution of this article points to the performance of the Volt-Watt (V-W) control function in single-stage inverters, which allows the maximum generation of instantaneous active power, acting directly on the maximum power point tracking algorithm, this strategy being validated by the CHIL simulation. The results show that the Volt-VAr and Volt-Watt control functions, acting at different levels of photovoltaic penetration, were effective in preventing the voltage profiles from violating the critical level imposed by the regulatory standard. Leading to the conclusion that its implementation directly in photovoltaic inverters entails a low cost and a complementary solution for the new challenges of electrical systems.
|
|
| 4. |
- de Oliveira, Janaina Goncalves, et al.
(författare)
-
Harmonic Mitigation in a Coreless Double-Wound Flywheel Machine : Experimental Verification
- 2015
-
Ingår i: International Journal of Emerging Electric Power Systems. - : WALTER DE GRUYTER GMBH. - 2194-5756 .- 1553-779X. ; 16:3, s. 243-251
-
Tidskriftsartikel (refereegranskat)abstract
- This paper aims at analyzing harmonics and interharmonics present in a flywheel-based driveline developed at Uppsala University. The flywheel machine is a permanent magnet synchronous machine with two sets of windings in the stator, with a Wye-Wye connection as standard. Different sources of harmonic distortion have been evaluated. Flywheel machine simulations are performed in finite element method (FEM) (Comsol) and experimental verifications are presented. Several methods for harmonic mitigation have been evaluated. The driveline suffers almost exclusively from second-order harmonics but the THD (total harmonic distortion) seldom exceeds 5%. Very little interharmonics are present. A Delta-Wye connection of the flywheel eliminates most of the harmonics but at the expense of a high-phase current through the Delta connection. Grounding the neutral conductor in Wye connections increases the distortion.
|
|
| 5. |
- Mayrink Jr, Sergio, et al.
(författare)
-
Regenerative Braking for Energy Recovering in Diesel-Electric Freight Trains : A Technical and Economic Evaluation
- 2020
-
Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- The present work evaluates the application of regenerative braking for energy recovery in diesel-electric freight trains to increase efficiency and to improve decarbonization. The energy from regenerative braking has to be stored onboard when the track is not electrified. Different technologies of energy recovery are presented and discussed. The energy balance of an existing route is presented and simulated for different battery sizes. The analysis is illustrated with experimental data from an important Brazilian railway. Results show that the energy recovery from regenerative brake is a feasible investment and may be recommended to increase the efficiency in transportation and also to improve the low carbon mobility in railway systems.
|
|
| 6. |
- Silva Júnior, Dalmo C., et al.
(författare)
-
Control of Smart Inverters with Automated Decisions in Microgrid
- 2023
-
Ingår i: Journal of Control, Automation and Electrical Systems. - : Springer. - 2195-3880 .- 2195-3899. ; 34, s. 1028-1042
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, a smart inverter model that executes ancillary services with automated decisions is presented, such as powersharing and voltage and frequency stabilization, compensation of unbalance voltage, mitigation of harmonic content, and thebalance of generation and demand. The droop control was utilized for power-sharing between the distributed generations; themitigation of negative-sequence voltage is used for unbalanced voltage compensation, and finally, a feed-forward current isadopted for harmonic compensation. Therefore, the smart inverter was controlled through a supervisory system, identifyingwhich ancillary function to activate at certain times. Results show the successful operation of the system and can be used asvalidation of the proposed control strategies, including the automated decisions in the microgrid
|
|
| 7. |
- Abrahamsson, Johan, et al.
(författare)
-
On the Efficiency of a Two-Power-Level Flywheel-Based All-Electric Driveline
- 2012
-
Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 5:8, s. 2794-2817
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents experimental results on an innovative electric driveline employing a kinetic energy storage device as energy buffer. A conceptual division of losses in the system was created, separating the complete system into three parts according to their function. This conceptualization of the system yielded a meaningful definition of the concept of efficiency. Additionally, a thorough theoretical framework for the prediction of losses associated with energy storage and transfer in the system was developed. A large number of spin-down tests at varying pressure levels were performed. A separation of the measured data into the different physical processes responsible for power loss was achieved from the corresponding dependence on rotational velocity. This comparison yielded an estimate of the perpendicular resistivity of the stranded copper conductor of 2.5 x 10(-8) +/- 3.5 x 10(-9). Further, power and energy were measured system-wide during operation, and an analysis of the losses was performed. The analytical solution was able to reproduce the measured distribution of losses in the system to an accuracy of 4.7% (95% CI). It was found that the losses attributed to the function of kinetic energy storage in the system amounted to between 45% and 65%, depending on usage.
|
|
| 8. |
- Abrahamsson, Johan, et al.
(författare)
-
Prototype of electric driveline with magnetically levitated double wound motor
- 2010
-
Ingår i: Electrical Machines (ICEM), 2010 XIX International Conference on.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the ongoing work of constructing a complete driveline for an electric road vehicle, using a flywheel as auxiliary energy storage. The flywheel energy storage system (FESS) is connected in series between the main energy storage (batteries) and the wheel motor of the vehicle, allowing the batteries to deliver power to the system in an optimized way, while at the same time making efficient use of regenerative braking. A double wound permanent magnet electric machine is used to electrically separate the two sides. In order to minimize losses, the machine has a double rotor configuration and is suspended with magnetic bearings. A bench test set-up is being constructed to investigate the properties of this system in detail. This set-up will achieve a level of power and energy close to that of a full scale system. This will allow measurements of complete drive cycles to be performed, improving the understanding of the constituting components and optimization of the complete system.
|
|
| 9. |
|
|
| 10. |
|
|
