Systemic Design Methodologies for Electrical Energy Systems

Analysis, Synthesis and Management

Xavier Roboam, Xavier Roboam

• Publisher: Wiley-ISTE
• Year: 2012
• ISBN:
  9781118569672
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Power Resources
• Index: Technology & Engineering

This book proposes systemic design methodologies applied to electrical energy systems, in particular analysis and system management, modeling and sizing tools.
It includes 8 chapters: after an introduction to the systemic approach (history, basics & fundamental issues, index terms) for designing energy systems, this book presents two different graphical formalisms especially dedicated to multidisciplinary devices modeling, synthesis and analysis: Bond Graph and COG/EMR. Other systemic analysis approaches for quality and stability of systems, as well as for safety and robustness analysis tools are also proposed. One chapter is dedicated to energy management and another is focused on Monte Carlo algorithms for electrical systems and networks sizing.
The aim of this book is to summarize design methodologies based in particular on a systemic viewpoint, by considering the system as a whole. These methods and tools are proposed by the most important French research laboratories, which have many scientific partnerships with other European and international research institutions. Scientists and engineers in the field of electrical engineering, especially teachers/researchers because of the focus on methodological issues, will find this book extremely useful, as will PhD and Masters students in this field.

Chapter 1

Introduction to Systemic Design (1)

This book focuses on “energy conversion systems”, especially on electric energy, which is most of the time combined with other forms of energy using different conversion mechanisms. If “energy” gives them very specific properties that we develop in this chapter and that we explore in the methods introduced in this book, their properties are more generally those of “systems” in the sense of “systems theory” or the “science of systems”. This is especially observable as systems of conversion of energy are highly heterogeneous in several respects: they show indeed, in the same way as most modern technological artifacts, energetic elements, but also automatisms to manage the energy flows, software for data processing and even human operators directly involved in their operation. The objective of this chapter is to introduce and specify the concepts and terms associated with “systems or devices for the conversion of energy” and with the associated “methodologies of systemic design”, in relation to the science of systems as they are considered and discussed in this book. One of the permanent difficulties of an interdisciplinary dialog is the polysemy1 of identical terms with different meanings depending on the cultural origin and the specialty of the speakers. Therefore, in this chapter, we specify as much as possible the meaning that we give to terms that may have several meanings, not to lay down a prescriptive definition but simply to define the exact range within this book. In particular every notion qualified as “systemic” means that it is considered in the sense of “systems theory” or the “science of systems”.

Energy is a unifying concept of physics and even a universal concept of science. It allows us to describe phenomena that seem very different that are observed in all fields of nature and considered as manifestations of different forms of “energy”. Thus, many difficult problems are solved efficiently, and even smartly, by wisely using the properties of energy: the methods introduced in this book. The fundamental properties of energy can only be fully appreciated when associated with entropy, through a combined and modern reading of the first and second principles of thermodynamics. Beyond the pure scientific context, these properties shed new light on the current energy challenges and the concrete issues of our societies in the context of sustainable development [BAL 01a, DIN 07].

In this chapter, after briefly defining the general notion of “system” and of the “science of systems” or “systems theory”, as considered in the book, we develop these concepts with a historical analysis of their improvement until the modern period. Then, modeling and simulation being crucial operations in systemic approaches, we introduce the main and specific properties of systemic models. We then introduce the properties that systems of energy conversion, as being a particular class of systems, inherit, specifically from the properties of energy after recalling and analyzing the latter, as well as the properties of entropy that are just as important. Having considered these general and specifically targeting problems in the following chapters, we finally introduce the systemic design of technological devices of conversion of energy as we perceive them today.

REMARKS 1.1.– In this chapter, only the principal concepts are developed. The chapter also includes a “glossary of the science of systems”, defining the terms used in this book. Indeed, with each definition calling for different terms that need to be defined in the context of the science of systems, the presentation of the glossary in alphabetic order seems most suitable. Glossary terms are indicated in underlined italics in order to distinguish them from other italic texts that are used for emphasis in the text. Moreover, the bibliography, in addition to the references presented in the text, together make up a backup, which was especially used to write this chapter.

1.1. The system and the science of systems

The term “system” comes from the Greek word “systêma”, which means “ensemble”. We first define it as an “ensemble of components in dynamic interaction making up an organized whole”. This short definition already brings out some fundamental properties of systems, which also establish the “science of systems” and “systems theory” in their different declensions. To specify them, we need to define an ensemble of notions and associated terms for which the meanings and the definitions are themselves interrelated. In addition to the following developments, we refer to the “glossary of systems theory” at the end of the chapter.

1.1.1. First notions of systems and systems theory

1.1.1.1. Notion of system

The system makes up an entity that seems identifiable in its environment by its boundaries and its properties. In general, it is neither isolated nor closed, but open; therefore, it is able to exchange energy (work or heat) and/or matter and/or information with its environment. Thus, it also exchanges entropy with its environment. Electromagnetic actuators, a living cell, a car, a city, are thereby defined and identifiable as systems, open to their environment. We can see in Chapter 1 of [ROB 12] the importance of a suitable and compact representation of the environment upstream of the systemic design process2.

L. Von Bertalanffy, founder of the first “general systems theory”, defined the system as a “complex of elements in interaction”. This definition is apparently very simple but is, in fact, very typical. Indeed, with no interactions or associations, there is no system. The properties of a system not only result from the components that constitute it, but also and especially from the bidirectional relationships or interactions between these components and with the environment of the system. These components can be heterogeneous, material or immaterial. From combining all these (possible nonlinear) interactions, the system shows properties at an ensemble level and does not appear at the component level when considered individually. It is then said that there is an emergence of properties, properties that are only seen at the level of a considered system as a whole and which make up an expression of its complexity. It is in this sense that the system seems like “an organized whole”, which “is greater than the sum of its components” by its own emergent properties, which do not result from a simple addition operation of its component properties. Similarly, part of the system that shows specific properties while being in the system may lose them once separated from it. This part, as well as the system, will lose the properties made up by their interactions. This emergence property, integral to the system, introduces a particular difficulty for the possible operational definition of subsystems or for the presentation of a system at different scales to ease its study (level of resolution, granularity and modularity): to accept this difficulty is crucial for the study of systems. We will eventually separate strong couplings from weak couplings between subsystems, i.e. having or not an effect on the emergence of these new properties at a system level. Weak couplings allow, depending on a particular hypothesis, a suitable partition of the system with the emergence of properties that characterize the considered system.

These first properties of the “system”, as we have introduced them above, mean that their study as a “system” cannot be carried out by an approach of decomposition-reconstruction, a “reductionist” approach, but by a so-called “holistic” global approach. This aspect is characteristic of the systemic approach. Consequently, the system is made intelligible by the simultaneous identification of the elements (objects or components) that make it up and especially of their interactions (bidirectional relations) following a conjunctive logic: this approach makes up the “science of systems” [LEM 95]. More than the simple addition of components, the system then emerges as composed of organs, which fulfill their functions and participate in its organization: this is exactly what gives the properties of being a system. The special description of an organ by its function, rather than its physical composition, introduces and evolves the notion of finality of the organ or of its system. This “finalist” aspect has encouraged some reservations about the scientific legitimacy of the systematic approach for 40 years and is still controversial. However, this difficulty is solvable nowadays within the large framework of theories of complexity: we will come back to this later.

The organization in its entirety, by its identified properties, can also be perceived as the finality of the identified system in its environment. This finality can be certified (intentionally) or interpreted (from the observation) and can evolve. Indeed, the exchanges that the system makes with its environment by being open enable it to maintain and develop its organization, which leads to its evolution. The environment thereby influences this evolution by the constraints that it has on the system. These constraints are expressed by boundary conditions of the system. Sometimes, we may also consider a co-evolution of the system combined with its environment. The influence becomes interaction and a part of the environment has to be integrated in the system. This co-evolution is not uncommon. It occurs when the “sources” in the environment cannot be considered as an “infinite view of the system”. This is the well-known case of the evolution of life and the atmosphere on Earth enriched in oxygen by photosynthesis. The consequences of human activity, more particularly in terms of energy, on the availability of natural resources or the climatic system can be comparable. At a lower scale, in the continuity of a co-evolution of the road infrastructure with automobiles [ROS 95], an increase in electrical vehicles in a world full of petrol vehicles would eventually modify the traffic conditions, and consequently the profiles considered to build new optimized vehicles. In addition, new electrical vehicles or hybrids “connected” to the power grid while parking and put in place for a dynamical management by their electrical storage capacity following the concept of “Vehicle to Grid” (V2G) will enhance the co-evolution of infrastructures toward new smart grids and vehicles (electrical architecture, energy management), which will be seen as “vehicles” and “organs of storage”.

The system is therefore identified by “what it does” (what it accomplishes in its environment), rather than by “its apparent constitution” (what it is or what it seems to be). A living cell, an automobile, and an actuator are easily identifiable, despite their wide range of internal constitution: they are then indeed considered and designed by their global function in the first place.

These few elements lay down the fundamental properties of systems and allow us to define a “general system” regrouping the four following concepts: finality, environment, functions and evolution [LEM 95]. However, it is all about specifying and completing them in order to enable an operational use in ...

Table of contents

• Cover
• Title Page
• Copyright
• Preface
• Chapter 1: Introduction to Systemic Design
• Chapter 2: Military Culture and Diversity
• Chapter 3: Women in the Military
• Chapter 4: Ethical Decision Making in Military Social Work
• Chapter 5: Secondary Trauma in Military Social Work
• Chapter 6: Posttraumatic Stress Disorder (PTSD) in Veterans
• Chapter 7: The Neurobiology of PTSD and Cognitive Processing Therapy (CPT)
• Chapter 8: Treating Combat-Related PTSD With Virtual Reality Exposure Therapy
• List of Authors
• Index