M. Godoy Simões

An Energy Management System for Building Structures Using a Multi-Agent Decision-Making Control Methodology

Aligned towards net zero energy building goals, building energy management systems will consider energy utilization efficiency improvement, energy cost reduction and renewable energy technology utilization to serve the local energy loads in building structures with dispersed resources. The distributed management of building energy system in this paper describes a semi-centralized decision making methodology using multi-agent systems for building energy management system in electrical, heating and cooling energy zones with combined heat and power system optimization aimed at improving energy efficiency and reducing energy cost. The semi-centralized decision making process will be implemented in a case study to pursue minimum energy cost.

Smart-grid technologies and progress in Europe and the USA

The work discusses historical and technical events in USA and Europe over the last few years that are aimed at modernizing the electric power grid. The US federal government has ratified the “smart grid” as official policy for modernizing the electricity grid with provisions for timely information and control options to consumers and deployment of “smart” technologies. European countries are unified in researching and developing related technologies through various structures supported by the European Union. This paper presents the development of smart grids and in-depth analysis of the methodologies, milestones and expected evolutions of grid technologies that will transform our society in the very near future.

LCL filter design and performance analysis for small wind turbine systems

The use of power converter is becoming very popular nowadays to maximize the power extraction from wind as well as interfacing the wind generator with the power grid. LCL filter plays an important role for interconnecting the inverter to the utility grid. Although several researchers designed LCL filtering based inverters, it has been still lacking in the literature a consisted and systematic design methodology that considers statespace mathematical models for delta and wye connected capacitors, considering grounding options and related harmonics mitigation. This paper discusses a comprehensive design of the output LCL filter for the grid-interconnected inverters used in small scale wind energy conversion system, with a practical industrial point of view. The proposed design methodology can also be used in medium and large scale grid connected wind and photovoltaic systems. This paper has practical applicability by describing all the procedural methodology and analysis in how to design LCL filters supported by an in-depth simulation study.

A conceptual scheme for cyber-physical systems based energy management in building structures

Concerns about energy efficiency and carbon footprints are becoming more significant in the power industry and public policy, as evidenced by the concerted shift to renewable energy sources and energy conservation paradigms. One of the largest consumers of energy in the US is the residential and commercial buildings sector. This paper explores a conceptual framework of a cyber-physical system (CPS) for energy management in such structures, viz. a Cyber-enabled Efficient Building Energy Management System (CEBEMS), aimed at attaining some level of energy self-sufficiency.

PQ, DQ and CPT control methods for shunt active compensators — A comparative study

This paper investigates three different control techniques for controlling shunt active compensators for harmonic, reactive power and unbalance compensation. The considered methods were the instantaneous real and imaginary power theory (PQ), the Conservative Power Theory (CPT) and the synchronous reference frame method (DQ). So, the major goal is to explore the main similarities and differences in terms of steady state performance, dynamic response and computational complexity of each compensation method. Additionally, the paper also discusses how to achieve selective compensation by means of every technique, by means of suitable power and current decompositions. A three-phase grid with unbalanced non-linear load and non-negligible line impedance was used for comparing the approaches under ideal and deteriorated voltage conditions.

Single phase and three phase P+Resonant based grid connected inverters with reactive power and harmonic compensation capabilities

Designing optimized and more efficient controllers for grid connected inverters is a challenge. Conventionally such controllers were established in dq or rotational frame; however, recently stationary or alpha-beta frame has found special interest due to some unique features that it can offer for grid connected inverters. On dq frame variables turn into constants after passing through transform matrixes, so PI controllers that have infinite gain on DC quantities are widely used. But PI controllers are unable to achieve zero steady state error in stationary frame and P+Resonant controllers which have infinite gain on their resonant frequency have been implemented instead. This paper will explain step by step P+Resonant based inverter controllers design for grid connected single and three phase inverters with reactive power compensation and then a novel approach for grid harmonics compensation will be implemented.

Short transient recovery of low voltage-grid-tied DC distributed generation

This paper presents a design framework for a power electronic interface for a grid-tied (GT) low voltage DC distributed generation (DG) with short transient recovery between GT mode and islanding mode. The proposed interface contains controlled unidirectional and bidirectional floating interleaved converters (FIC), in addition to a smart grid-tied inverter (GTI) to optimize the overall performance of the DG from different perspectives and provide compatible AC voltage to the grid and local loads during islanding mode, GT operating mode and transition mode. FIC has been applied in order to address the low gain issue in photovoltaic (PV) based DGs, and bidirectional FIC is used in order to add the Energy Storage Unit (ESU) to the system. A comprehensive study on bidirectional FIC operating modes indicates that a single-controller scheme can be applied to control the overall operation of this converter in the buck and boost modes. By using this method, the transient response caused by changing controllers between the boost and buck modes will be recovered. Finally, a battery lifetime management algorithm is proposed for increasing the storage system reliability. The effectiveness of the proposed framework has been verified using simulation results in MATLAB and PSIM software; experimental work is under progress.

Neural network based prediction of mooring forces in floating production storage and offloading systems

The paper explicates the development of a neural network based prediction of mooring forces of a deep-sea oil exploitation production process. The evolution of a neural network simulator for analysis of the dynamic behavior of a system consisting of a turret-FPSO (floating production storage and off loading) and a shuttle ship in tandem configuration is described. The turret-FPSO is a ship type floating unit and its surge and sway motions are avoided by mooring lines connected in the turret. The study of the dynamics of this system is difficult because there are complex forces interaction due to currents, waves and winds. In general, the mathematical model that represents the dynamics of both ships involves a set of nonlinear equations requiring several parameters very difficult to obtain. In order to deal with such complex modeling a neural network has been devised to simulate the system and to incorporate actual data, so as to identify the dynamics of the system and to study stability influence avoiding possible collisions and mooring line stresses.

A Five-Phase Brushless DC-Machine Direct Drive System

Abstract The paper describes the design, analysis, simulation, modeling and control implementation of a high-torque, low-speed, multiphase, permanent magnet, brushless dc machine. The main focus is on issues regarding the high-level modeling, comprised of a transient model, in conjunction with corresponding experimental evaluation. The general assumption of ideal rectangular current waveforms for brushless-dc machines is not encountered in practice; the existing distortions can be modeled by incorporating mutual inductance and armature reaction in order to avoid erroneous control strategy development. Analyses are made to put together modeling efforts with the expected behavior so as to build a model of the expected behavior so realistic simulation results can be verified. Coherent and consistent results were observed by comparing simulation and experimentation. A digital signalprocessing(DSP) system control was developed to implement the strategies that corroborate the work.

Application of compressive sensing for distributed and structured power line outage detection in smart grids

Fast and accurate identification and localization of power line outages is one of the critical issues for efficient monitoring and control tasks in future smart grids. In this work, considering the whole power network (PN) as a single graph, the recently introduced sparse formulation of the Power line Outage Identification (POI-SRP) is represented. Our main contribution is to improve and generalize the POI-SRP results for single and multiple line outage identification using matrix analysis and the structured pattern in multiple POI. We address the high coherence and high correlation issues in corresponding POI-SRP sensing matrices. In order to solve these problems, we perform a comprehensive study on the corresponding matrices of the IEEE standard networks in POI-SRP. Our main approach will be based on the necessary and sufficient conditions that these matrices should satisfy in order to be applicable to the Sparse Recovery Problem (SRP). First, we discuss the effect that node-line connection structures in the PN model have on the coherence. We describe a modification of the PN model in order to decrease the coherence. Next, using the IEEE standard 118-BUS as a case study, we discuss how the high correlation problem can be solved by applying mathematical matrix analysis such as matrix decomposition and improving the final POI results. The third main contribution is the identification of the structured outages in POI-SRP. In this work, the boundary conditions of the Clustered OMP recovery algorithm are modified (MCOMP) and finally it will be shown how the existence of structured sparsity in multiple POI problems (Structured-POI-SRP) helps MCOMP to improve the POI results.