http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

Of Theory and Practice

Due to increasing concerns about global warming, greenhouse gas emissions, and the depletion of fossil fuels, the electric vehicles (EVs) receive massive popularity due to their performances and efficiencies in recent decades. EVs have already been widely accepted in the automotive industries considering the most promising replacements in reducing CO2 emissions and global environmental issues. Lithium-ion batteries have attained huge attention in EVs application due to their lucrative features such as lightweight, fast charging, high energy density, low self-discharge and long lifespan. This paper comprehensively reviews the lithium-ion battery state of charge (SOC) estimation and its management system towards the sustainable future EV applications. The significance of battery management system (BMS) employing lithium-ion batteries is presented, which can guarantee a reliable and safe operation and assess the battery SOC. The review identifies that the SOC is a crucial parameter as it signifies the remaining available energy in a battery that provides an idea about charging/discharging strategies and protect the battery from overcharging/over discharging. It is also observed that the SOC of the existing lithium-ion batteries have a good contribution to run the EVs safely and efficiently with their charging/discharging capabilities. However, they still have some challenges due to their complex electro-chemical reactions, performance degradation and lack of accuracy towards the enhancement of battery performance and life. The classification of the estimation methodologies to estimate SOC focusing with the estimation model/algorithm, benefits, drawbacks and estimation error are extensively reviewed. The review highlights many factors and challenges with possible recommendations for the development of BMS and estimation of SOC in next-generation EV applications. All the highlighted insights of this review will widen the increasing efforts towards the development of the advanced SOC estimation method and energy management system of lithium-ion battery for the future high-tech EV applications.

A review of lithium-ion battery state of charge estimation and management system in electric vehicle applications: Challenges and recommendations

Microgrids are now emerging from lab benches and pilot demonstration sites into commercial markets, driven by technological improvements, falling costs, a proven track record, and growing recognition of their benefits. They are being used to improve reliability and resilience of electrical grids, to manage the addition of distributed clean energy resources like wind and solar photovoltaic (PV) generation to reduce fossil fuel emissions, and to provide electricity in areas not served by centralized electrical infrastructure. This review article (1) explains what a microgrid is, and (2) provides a multi-disciplinary portrait of today's microgrid drivers, real-world applications, challenges, and future prospects.

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Microgrids: A review of technologies, key drivers, and outstanding issues

A comprehensive review of lithium-ion batteries used in hybrid and electric vehicles at cold temperatures

High energy battery systems have recently appeared as an alternative Internal-Conbustion-Engine (ICE) based vehicle's powertrains. As a conquence, over the last few years, automotive manufacturers focused their research on electrochemical storage for electric (EV) and hybrid electric vehicles (HEV). In a lot of hybrid or electric applications, Lithium based batteries are used. To protect Lithium batteries and optimize their utilisation, a good State-of-Charge determiation is necessary. So three adaptive system used in the literature are presented in this article, the Kalman Filter, the Artificial Neural Network and the Fuzzy Logic systems.

Review of adaptive systems for lithium batteries State-of-Charge and State-of-Health estimation

In this paper, a multiphysical proton exchange membrane fuel cell stack model, which is suitable for real-time emulation is presented. The model covers three physical domains: electrical, fluidic, and thermal. A Ballard 1.2 kW 47 cells fuel cell stack model is introduced. The corresponding fuel cell system auxiliary models are given based on experimental tests. Based on the modeling equations, the fuel cell dynamic phenomena in different physical domains are analyzed and the corresponding time constant expressions are given. Using the real-time stack model, a fuel cell stack emulator based on a buck converter is used to emulate the fuel cell stack electrical part. The experimental results show that the emulator can reproduce the real-stack behavior with a great agreement. Such a fuel cell stack emulator can be used for hardware-in-the-loop applications, in order to test and validate the fuel cell system design.

PEM Fuel Cell Stack Modeling for Real-Time Emulation in Hardware-in-the-Loop Applications

This paper discusses historical and technical events in the U.S. and Europe over the last few years that are aimed at modernizing the electric power grid. The U.S. federal government has ratified the “smart grid initiative” as the official policy for modernizing the electricity grid including unprecedented 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 an analysis of the methodologies, milestones, and expected evolutions of grid technologies that will transform society in the near future.

A Comparison of Smart Grid Technologies and Progresses in Europe and the U.S.

This paper describes two different control strategies for a fuel-cell-based hybrid electric vehicle (FCHEV). The offline strategy is based on dynamic programming, and the online strategy is based on an optimized fuzzy logic controller. These two strategies are then compared. Finally, the fuzzy logic controller is validated using a real FCHEV.

Control Strategies for Fuel-Cell-Based Hybrid Electric Vehicles: From Offline to Online and Experimental Results

The electric grid is currently undergoing important changes: it is evolving from an entirely centralized structure to a decentralized one, mainly due to the massive development of distributed renewable energy sources. This evolution toward what we now call the smart grid requires new control methods. These methods must be able to withstand new requirements, such as the highly distributed nature of the grid, the ability to run in islanding mode, the intermittency of renewable energy sources and the limited bandwidth for communications. Multi-agent systems (MAS) have characteristics that meet these requirements. In contrary to classical analytical methods, the grid is considered as a collection of simple entities called agents corresponding to sources, loads and other components, evolving in a given environment. A certain degree of distributed or collective intelligence can be achieved through the interaction of these agents with each other, cooperating or competing to reach their goals. This article is a short review of several multi-agent systems published in the literature and used for grid energy management. It presents a number of concepts and experiments used by researchers to apply this promising method. Various approaches and their results are compared, in order to give the reader a global perspective of the state of the art in this precise domain.

Benjamin Blunier

Papers

Review of adaptive systems for lithium batteries State-of-Charge and State-of-Health estimation

PEM Fuel Cell Stack Modeling for Real-Time Emulation in Hardware-in-the-Loop Applications

A Comparison of Smart Grid Technologies and Progresses in Europe and the U.S.

Control Strategies for Fuel-Cell-Based Hybrid Electric Vehicles: From Offline to Online and Experimental Results

Multi-agent systems for grid energy management: A short review