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Publications

Publications by CPES

2022

qTSL: A Multilayer Control Framework for Managing Capacity, Temperature, Stress, and Losses in Hybrid Balancing Systems

Authors
de Castro, R; Pereira, H; Araujo, RE; Barreras, JV; Pangborn, HC;

Publication
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY

Abstract
This work deals with the design and validation of a control strategy for hybrid balancing systems (HBSs), an emerging concept that joins battery equalization and hybridization with supercapacitors (SCs) in the same system. To control this system, we propose a two-layer model predictive control (MPC) framework. The first layer determines the optimal state-of-charge (SoC) reference for the SCs considering long load forecasts and simple pack-level battery models. The second MPC layer tracks this reference and performs charge and temperature equalization, employing more complex module-level battery models and short load forecasts. This division of control tasks into two layers, running at different time scales and model complexities, enables us to reduce computational effort with a small loss of control performance. Experimental validation in a small-scale laboratory prototype demonstrates the effectiveness of the proposed approach in reducing charge, temperature, and stress in the battery pack.

2022

Linear and nonlinear systems in continuous time: application to power converters

Authors
Silveira, AM; de Castro, R; Araújo, RE;

Publication
Encyclopedia of Electrical and Electronic Power Engineering: Volumes 1-3

Abstract
Modeling is a key step in the design of energy and control systems. It allows us to simulate and predict the behavior of electronics converters, even before constructing them. This is instrumental, for example, for sizing, component selection and preliminary validation of the converter's functionality. It also enables us to design model-based controllers for the converter and regulate the amount of transferred power, which can be done using simulation tools. This article introduces the main tools employed in the mathematical modeling of power converters, with a particular focus on linear approximations and average models. © 2023 Elsevier Inc. All rights reserved.

2022

Properties and control stability analysis of linear and nonlinear systems: applications to power converters

Authors
de Castro, R; Silveira, AM; Araújo, RE;

Publication
Encyclopedia of Electrical and Electronic Power Engineering: Volumes 1-3

Abstract
The goal of this article is to introduce the fundamental notions and concepts of stability analysis for linear and nonlinear systems in the context of electronic power conversion. Power electronic circuits have strong nonlinear behavior in their essence; often we need to linearize them to understand their properties and study their stability with the applied control laws. We present different concepts of stability (internal, input-output, Lyapunov-based), observability and controllability, as well as practical tests to check these properties. We then apply these tests in the context of a single power converter example, a DC/DC boost converter. © 2023 Elsevier Inc. All rights reserved.

2022

Core Loss Distribution in a Switched Reluctance Motor - Linear and Nonlinear Analysis

Authors
Melo, P; Araujo, RE;

Publication
2022 IEEE VEHICLE POWER AND PROPULSION CONFERENCE (VPPC)

Abstract
Switched reluctance machines (SRM) are simple, robust and fault tolerant machines, usually operating under strong nonlinear characteristics. Hence, SRM modeling is a most demanding task, in particular core losses. Non-sinusoidal flux density waveforms in different stator and rotor core sections, in addition to lamination non-uniform distribution are challenging phenomena to be addressed. This is still an ongoing research field. The purpose of this paper is to develop a comparative analysis between a linear and non-linear simulation model for core loss distribution in a three-phase 6/4 SRM. Five different steady-state operation modes will be addressed.

2022

MV-LV network-secure bidding optimisation of an aggregator of prosumers in real-time energy and reserve markets

Authors
Iria, J; Scott, P; Attarha, A; Gordon, D; Franklin, E;

Publication
Energy

Abstract

2022

A Multiobjective Approach for the Optimal Placement of Protection and Control Devices in Distribution Networks With Microgrids

Authors
REIZ, C; DE LIMA, TD; LEITE, JB; JAVADI, MS; GOUVEIA, CS;

Publication
IEEE ACCESS

Abstract
Protection and control systems represent an essential part of distribution networks by ensuring the physical integrity of components and by improving system reliability. Protection devices isolate a portion of the network affected by a fault, while control devices reduce the number of de-energized loads by transferring loads to neighboring feeders. The integration of distributed generation has the potential to enhance the continuity of energy services through islanding operation during outage conditions. In this context, this study presents a multi-objective optimization approach for sizing and allocating protection and control devices in distribution networks with microgrids supplied by renewable energy sources. Reclosers, fuses, remote-controlled switches, and directional relays are considered in the formulation. Demand and generation uncertainties define the islanding operation and the load transfer possibilities. A non-dominated sorting genetic algorithm is applied in the solution of the allocation problem considering two conflicting objectives: cost of energy not supplied and equipment cost. The compromise programming is then performed to achieve the best solution from the Pareto front. The results show interesting setups for the protection system and viability of islanding operation.

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