2017
Autores
Ferreira J.;
Publicação
U.Porto Journal of Engineering
Abstract
The DC/DC boost converter is described as a time variant system. State-Space is one of the methods used to approach a time variant system to an invariant time linear system. The present document focuses on a comparative approach of output voltage regulation and system stability and performance. For this document, there were made MatLab tests of PI and PD controllers, with and without fuzzy control.
2017
Autores
Varajao, D; Araujo, RE; Miranda, LM; Pecas Lopes, JP; Weise, ND;
Publicação
ELECTRIC POWER SYSTEMS RESEARCH
Abstract
This paper describes a new current control method that enhances the dynamic performance of a singlephase bidirectional AC-DC battery charger to provide a high-frequency link between the grid and electric vehicle. The single-stage structure and the bidirectional power flow make the matrix converter an attractive solution for electric vehicle (EV) battery charging applications in the context of smart grids. The operating principles and modulation method are analyzed and discussed in detail. Furthermore, a current controller improved with a Smith predictor is proposed to decrease the phase delay in the measurement of the average current in the battery pack. The SP reduces the rise time to around a third and the settling time to half when compared with a PI controller. Simulations and experimental results from a laboratory prototype are shown to verify the feasibility of the proposed control scheme.
2017
Autores
Gouveia, J; Gouveia, C; Rodrigues, J; Bessa, R; Madureira, AG; Pinto, R; Moreira, CL; Lopes, JAP;
Publicação
2017 IEEE MANCHESTER POWERTECH
Abstract
A distinctive characteristic of a Microgrid (MG) system is related to the ability of operating autonomously. However, the stability of the system relies in storage and generation availability, providing frequency and voltage regulation. Considering the deployment of distributed storage units in the Low Voltage network and of smart metering infrastructures, this paper presents an online tool for promoting an effective coordination of MG flexible resources in order ensure a secure autonomous operation and maximize the time that the MG is able to operate islanded from the main grid. The tool determines a priori an emergency operation plan for the next hours, based on load and microgeneration forecasting. The limited energy capacity of the distributed storage units participating in MG control is also considered.
2017
Autores
Abreu, C; Rua, D; Costa, T; Machado, P; Pecas Lopes, JAP; Heleno, M;
Publicação
2017 IEEE MANCHESTER POWERTECH
Abstract
This paper describes an energy management system that is being developed in the AnyPLACE project to support new energy services, like demand response, in residential buildings. In the project end-user interfaces are designed and implemented to allow the input of preferences regarding the flexible use of shiftable and thermal appliances. Monitoring and self-learning algorithm are used to allow additional information to be collected and an automation platform is available for the management and control of appliances. An energy management algorithm is presented that processes end-user preferences and devices characteristics to produce an optimal dispatch considering demand response incentives. Results show the successful implementation of an optimized energy scheduling.
2017
Autores
Resende, FO; Peças Lopes, JA;
Publicação
CIRED - Open Access Proceedings Journal
Abstract
2017
Autores
Ferreira, HL; Stankova, K; Lopes, JP; Slootweg, JG; Kling, WL;
Publicação
JOURNAL OF ENERGY STORAGE
Abstract
This paper deals with integration of energy storage systems into electricity markets. We explain why the energy storage systems increase flexibility of both power systems and energy markets and why such flexibility is desirable, particularly when variable renewable energy sources are being used in existing power systems. As opposed to the existing literature, our model includes a dual technology energy storage system, acting in two different markets. We introduce a mathematical formulation for this model applied to two Dutch electricity markets. Adopting optimal control approach with the goal to maximize the yearly benefit, we show that the dual energy storage system can be profitable already when the same buying/selling strategies are adopted for the working days and weekends. We show that the profitability (slightly) increases with different buying/selling strategies for the weekdays and weekends. Finally, we demonstrate how the yearly benefit varies with size and efficiency of the devices chosen and market prices. (C) 2017 Published by Elsevier Ltd.
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