Analysis and Design Considerations of an Electric Vehicle Powertrain regarding Energy Efficiency and Magnetic Field Exposure

En esta tesis se analiza el sistema de tracción de un vehículo eléctrico de batería desde el punto de vista de la eficiencia energética y de la exposición a campos magnéticos por parte de los pasajeros (radiación electromagnética). Este estudio incluye tanto el sistema de almacenamiento de energía como la máquina eléctrica, junto con la electrónica de potencia y los sistemas de control asociados a ambos. Los análisis y los resultados presentados en este texto están basados en modelos matemáticos, simulaciones por ordenador y ensayos experimentales a escala de laboratorio. La investigación llevada a cabo durante esta tesis tuvo siempre un marcado enfoque industrial, a pesar de estar desarrollada en un entorno de considerable carácter universitario. Las líneas de investigación acometidas tuvieron como destinatario final al diseñador y al fabricante del vehículo, a pesar de lo cual algunos de los resultados obtenidos son preliminares y/o excesivamente académicos para resultar de interés industrial. En el ámbito de la eficiencia energética, esta tesis estudia sistemas híbridos de almacenamiento de energía basados en una combinación de baterías de litio y supercondensadores. Este tipo de sistemas son analizados desde el punto de vista de la eficiencia mediante modelos matemáticos y simulaciones, cuantificando el impacto de ésta en otros parámetros tales como el envejecimiento de las baterías. Respecto a la máquina eléctrica, el estudio se ha centrado en máquinas síncronas de imanes permanentes. El análisis de la eficiencia considera tanto el diseño de la máquina como la estrategia de control, dejando parcialmente de lado el inversor y la técnica de modulación (que son incluidos en el estudio como fuentes adicionales de pérdidas, pero no como potenciales fuentes de optimización de la eficiencia). En este sentido, tanto la topología del inversor (trifásico, basado en IGBTs) como la técnica de modulación (control de corriente en banda de histéresis) se establecen desde el principio. El segundo aspecto estudiado en esta tesis es la exposición a campos magnéticos por parte de los pasajeros. Este tema se enfoca desde un punto de vista predictivo, y no desde un punto de vista de diagnóstico, puesto que se ha desarrollado una metodología para estimar el campo magnético generado por los dispositivos de potencia de un vehículo eléctrico. Esta metodología ha sido validada mediante ensayos de laboratorio. Otros aspectos importantes de esta contribución, además de la metodología en sí misma, son las consecuencias que se derivan de ella (por ejemplo, recomendaciones de diseño) y la comprensión del problema proporcionada por esta. Las principales contribuciones de esta tesis se listan a continuación: una recopilación de modelos de pérdidas correspondientes a la mayoría de dispositivos de potencia presentes en un vehículo eléctrico de batería, una metodología para analizar el funcionamiento de un sistema híbrido de almacenamiento de energía para aplicaciones de tracción, una explicación de cómo ponderar energéticamente los puntos de operación par-velocidad de un vehículo eléctrico (de utilidad para evaluar el rendimiento de una máquina eléctrica, por ejemplo), una propuesta de incluir un convertidor DC-DC en el sistema de tracción para minimizar las pérdidas globales del accionamiento (a pesar de las nuevas pérdidas introducidas por el propio DC-DC), una breve comparación entre dos tipos distintos de algoritmos de minimización de pérdidas para máquinas síncronas de imanes permanentes, una metodología predictiva para estimar la exposición a campos magnéticos por parte de los pasajeros de un vehículo eléctrico (debida a los equipos de potencia), y finalmente algunas conclusiones y recomendaciones de diseño respecto a dicha exposición a campos magnéticos. ABSTRACT This dissertation analyzes the powertrain of a battery electric vehicle, focusing on energy efficiency and passenger exposure to electromagnetic fields (electromagnetic radiation). This study comprises the energy storage system as well as the electric machine, along with their associated power electronics and control systems. The analysis and conclusions presented in this dissertation are based on mathematical models, computer simulations and laboratory scale tests. The research performed during this thesis was intended to be of industrial nature, despite being developed in a university. In this sense, the work described in this document was carried out thinking of both the designer and the manufacturer of the vehicle. However, some of the results obtained lack industrial readiness, and therefore they remain utterly academic. Regarding energy efficiency, hybrid energy storage systems consisting in lithium batteries, supercapacitors and up to two DC-DC power converters are considered. These kind of systems are analyzed by means of mathematical models and simulations from the energy efficiency point of view, quantifying its impact on other relevant aspects such as battery aging. Concerning the electric machine, permanent magnet synchronous machines are studied in this work. The energy efficiency analysis comprises the machine design and the control strategy, while the inverter and its modulation technique are taken into account but only as sources of further power losses, and not as potential sources for further efficiency optimization. In this sense, both the inverter topology (3-phase IGBT-based inverter) and the switching technique (hysteresis current control) are fixed from the beginning. The second aspect studied in this work is passenger exposure to magnetic fields. This topic is approached from the prediction point of view, rather than from the diagnosis point of view. In other words, a methodology to estimate the magnetic field generated by the power devices of an electric vehicle is proposed and analyzed in this dissertation. This methodology has been validated by laboratory tests. The most important aspects of this contribution, apart from the methodology itself, are the consequences (for instance, design guidelines) and the understanding of the magnetic radiation issue provided by it. The main contributions of this dissertation are listed next: a compilation of loss models for most of the power devices found in a battery electric vehicle powertrain, a simulation-based methodology to analyze hybrid energy storage performance in traction applications, an explanation of how to assign energy-based weights to different operating points in traction drives (useful when assessing electrical machine performance, for instance), a proposal to include one DC-DC converter in electric powertrains to minimize overall power losses in the system (despite the new losses added by the DC-DC), a brief comparison between two kinds of loss-minimization algorithms for permanent magnet synchronous machines in terms of adaptability and energy efficiency, a predictive methodology to estimate passenger magnetic field exposure due to power devices in an electric vehicle, and finally some useful conclusions and design guidelines concerning magnetic field exposure.

Chemically distinct transition states govern rapid dissociation of single L-selectin bonds under force

Carbohydrate–protein bonds interrupt the rapid flow of leukocytes in the circulation by initiation of rolling and tethering at vessel walls. The cell surface carbohydrate ligands are glycosylated proteins like the mucin P-selectin glycoprotein ligand-1 (PSGL-1), which bind ubiquitously to the family of E-, P-, and L-selectin proteins in membranes of leukocytes and endothelium. The current view is that carbohydrate–selectin bonds dissociate a few times per second, and the unbinding rate increases weakly with force. However, such studies have provided little insight into how numerous hydrogen bonds, a Ca2+ metal ion bond, and other interactions contribute to the mechanical strength of these attachments. Decorating a force probe with very dilute ligands and controlling touch to achieve rare single-bond events, we have varied the unbinding rates of carbohydrate–selectin bonds by detachment with ramps of force/time from 10 to 100,000 pN/sec. Testing PSGL-1, its outer 19 aa (19FT), and sialyl LewisX (sLeX) against L-selectin in vitro on glass microspheres and in situ on neutrophils, we found that the unbinding rates followed the same dependence on force and increased by nearly 1,000-fold as rupture forces rose from a few to ≈200 pN. Plotted on a logarithmic scale of loading rate, the rupture forces reveal two prominent energy barriers along the unbinding pathway. Strengths above 75 pN arise from rapid detachment (<0.01 sec) impeded by an inner barrier that requires a Ca2+ bond between a single sLeX and the lectin domain. Strengths below 75 pN occur under slow detachment (>0.01 sec) impeded by the outer barrier, which appears to involve an array of weak (putatively hydrogen) bonds.

Nitrogen management and the future of food: Lessons from the management of energy and carbon

The food system dominates anthropogenic disruption of the nitrogen cycle by generating excess fixed nitrogen. Excess fixed nitrogen, in various guises, augments the greenhouse effect, diminishes stratospheric ozone, promotes smog, contaminates drinking water, acidifies rain, eutrophies bays and estuaries, and stresses ecosystems. Yet, to date, regulatory efforts to limit these disruptions largely ignore the food system. There are many parallels between food and energy. Food is to nitrogen as energy is to carbon. Nitrogen fertilizer is analogous to fossil fuel. Organic agriculture and agricultural biotechnology play roles analogous to renewable energy and nuclear power in political discourse. Nutrition research resembles energy end-use analysis. Meat is the electricity of food. As the agriculture and food system evolves to contain its impacts on the nitrogen cycle, several lessons can be extracted from energy and carbon: (i) set the goal of ecosystem stabilization; (ii) search the entire production and consumption system (grain, livestock, food distribution, and diet) for opportunities to improve efficiency; (iii) implement cap-and-trade systems for fixed nitrogen; (iv) expand research at the intersection of agriculture and ecology, and (v) focus on the food choices of the prosperous. There are important nitrogen-carbon links. The global increase in fixed nitrogen may be fertilizing the Earth, transferring significant amounts of carbon from the atmosphere to the biosphere, and mitigating global warming. A modern biofuels industry someday may produce biofuels from crop residues or dedicated energy crops, reducing the rate of fossil fuel use, while losses of nitrogen and other nutrients are minimized.

Temporally and spectrally resolved subpicosecond energy transfer within the peripheral antenna complex (LH2) and from LH2 to the core antenna complex in photosynthetic purple bacteria.

We report studies of energy transfer from the 800-nm absorbing pigment (B800) to the 850-nm absorbing pigment (B850) of the LH2 peripheral antenna complex and from LH2 to the core antenna complex (LH1) in Rhodobacter (Rb.) sphaeroides. The B800 to B850 process was studied in membranes from a LH2-reaction center (no LH1) mutant of Rb. sphaeroides and the LH2 to LH1 transfer was studied in both the wild-type species and in LH2 mutants with blue-shifted B850. The measurements were performed by using approximately 100-fs pulses to probe the formation of acceptor excitations in a two-color pump-probe measurement. Our experiments reveal a B800 to B850 transfer time of approximately 0.7 ps at 296 K and energy transfer from LH2 to LH1 is characterized by a time constant of approximately 3 ps at 296 K and approximately 5 ps at 77 K. In the blue-shifted B850 mutants, the transfer time from B850 to LH1 becomes gradually longer with increasing blue-shift of the B850 band as a result of the decreasing spectral overlap between the antennae. The results have been used to produce a model for the association between the ring-like structures that are characteristic of both the LH2 and LH1 antennae.

Volatility spillovers for spot, futures, and ETF prices in energy and agriculture

The agricultural and energy industries are closely related, both biologically and financially. The paper discusses the relationship and the interactions on price and volatility, with special focus on the covolatility spillover effects for these two industries. The interaction and covolatility spillovers or the delayed effect of a returns shock in one asset on the subsequent volatility or covolatility in another asset, between the energy and agricultural industries is the primary emphasis of the paper. Although there has already been significant research on biofuel and biofuel-related crops, much of the previous research has sought to find a relationship among commodity prices. Only a few published papers have been concerned with volatility spillovers. However, it must be emphasized that there have been numerous technical errors in the theoretical and empirical research, which needs to be corrected. The paper not only considers futures prices as a widely-used hedging instrument, but also takes an interesting new hedging instrument, ETF, into account. ETF is regarded as index futures when investors manage their portfolios, so it is possible to calculate an optimal dynamic hedging ratio. This is a very useful and interesting application for the estimation and testing of volatility spillovers. In the empirical analysis, multivariate conditional volatility diagonal BEKK models are estimated for comparing patterns of covolatility spillovers. The paper provides a new way of analyzing and describing the patterns of covolatility spillovers, which should be useful for the future empirical analysis of estimating and testing covolatility spillover effects.

Renewable Energies and Community Associations: Providing Homeowners with Renewable Energy Options

As energy costs increase in Colorado more homeowners will need renewable energies to provide electricity, heating and cooling for their homes. Renewable energy technology and energy efficient measures have been available for decades but Homeowner Associations (HOA) has not permitted this technology into communities primarily because of aesthetics. In April 2008, House Bill 1270 was signed into law that gives homeowners the right to make their homes more energy efficient and install renewable energy generation devices. The purpose of this capstone is to enable HOAs with information on available technology and design guideline options that can be integrated into communities and thus encourage, instead of hinder, the use of renewable energy and energy efficient measures.

The Composition and Drivers of Energy Prices and Costs in Energy-Intensive Industries: The Case of Ceramics, Glass and Chemicals. CEPS Special Report No. 85, 27 March 2014

In May 2013, the European Commission received a mandate from the European Council to “to present an analysis of the composition and drivers of energy prices and costs in Member States, with a particular focus on the impact on households, SMEs and energy intensive industries, and looking more widely at the EU's competitiveness vis-à-vis its global economic counterparts”. Following such mandate and in view of the preparation by the Commission of a Communication and a Staff Working Document, DG Enterprise and Industry commissioned CEPS to carry out a set of studies aimed at providing well-grounded evidence about the evolution and composition of energy prices and costs at plant level within individual industry sectors. A team of CEPS researchers conducted the research, led by Christian Egenhofer and Lorna Schrefler. Vasileios Rizos served as Project Coordinator. Other CEPS researchers contributing to the project included: Fabio Genoese, Andrea Renda, Andrei Marcu, Julian Wieczorkiewicz, Susanna Roth, Federico Infelise, Giacomo Luchetta, Lorenzo Colantoni, Wijnand Stoefs, Jacopo Timini and Felice Simonelli. In addition to an introductory report entitled “About the Study and Cross-Sectoral Analysis”, CEPS prepared five sectoral case studies: two on ceramics (wall and floor tiles and bricks and roof tiles), two on chemicals (ammonia and chlorine) and one on flat glass. Each of these six studies has been consolidated in this single volume for free downloading on the CEPS website. The specific objective was to complement information already available at macro level with a bottom-up perspective on the operating conditions that industry stakeholders need to deal with, in terms of energy prices and costs. The approach chosen was based on case studies for a selected set (sub-)sectors amongst energy-intensive industries. A standard questionnaire was circulated and respondents were sampled according to specified criteria. Data and information collected were finally presented in a structured format in order to guarantee comparability of results between the different (sub-)sectors analysed. The complete set of files can also be downloaded from the European Commission’s website: http://ec.europa.eu/enterprise/newsroom/cf/itemdetail.cfm?item_id=7238&lang=en&title=Study-on-composition-and-drivers-of-energy-prices-and-costs-in-energy-intnsive-industries The results of the studies were presented at a CEPS Conference held on February 26th along with additional evidence from other similar studies. The presentations can be downloaded at: http://www.ceps.eu/event/level-and-drivers-eu-energy-prices-energy-inten...

Energy and climate - What is the new European Commission thinking? EPC Commentary, 30 September 2014

A visible change of priorities and re-structuring of portfolios in the new European Commission have raised questions about related policy implications especially for climate and energy policies. On the one hand, it is seen that the new structure with Vice Presidents as team leaders for groups of Commissioners could encourage much needed policy coordination between policy areas, such as climate and energy policies. At the same time there are questions over what this could mean for political priorities, to what extent the Vice Presidents will be able to guide policy-making and how responsibilities will be divided. No matter what the structure of the Commission, it is in the EU’s interest to ensure that its climate and energy policies form a framework for action that helps to reduce global emissions, fight climate change locally and globally, secure energy supplies, promote wider socio-economic interests and increase competitiveness – all at the same time.

Too high and too low: The problems with energy prices in the EU. OSW Commentary No. 122, 03.12.2013

On 11 October, the top executives of ten European energy companies, which jointly own about half of the European Union’s electricity generating capacity, warned that “energy security is no longer guaranteed” and once again called for changes to EU energy policy. Due to persistent adverse conditions in the energy market (linked to, for example, the exceptionally low wholesale energy prices) more and more conventional power plants are being closed down. According to sector representatives, this could lead to energy shortages being seen as early as this winter. Meanwhile, in an interview with The Daily Telegraph published in September of this year, the European industry commissioner Antonio Tajani warned – in a rather alarmist tone – of the disastrous consequences the rising energy prices could have on European industry. Amongst the reasons for the high prices of energy, Tajani mentioned the overambitious pace and methods used to increase the share of renewables in the sector. In a similar vein, EU President Herman Van Rompuy has highlighted the need to reduce energy costs as a top priority for EU energy policy1. The price of energy has become one of the central issues in the current EU energy debate. The high consumer price of energy – which has been rising steadily over the past several years – poses a serious challenge to both household and industrial users. Meanwhile, the declining wholesale prices are affecting the cost-effectiveness of energy production and the profits of energy companies. The current difficulties, however, are first and foremost a symptom of much wider problems related to the functioning of both the EU energy market as well as to the EU’s climate and energy policies.

Informational Barriers to Energy Efficiency - Theory and European Policies. Bruges European Economic Research (BEER) Papers 15/2009

This BEER addresses informational barriers to energy efficiency. It is a widely acknowledged result that an energy efficiency gap exists implying that the level of energy efficiency is at an inefficiently low level. Several barriers to energy efficiency create this gap and the presence of asymmetric information is likely to be one such barrier. In this article a theoretical framework is presented addressing the issues of moral hazard and adverse selection related to energy efficiency. Based on the theoretical framework, European policies on energy efficiency are evaluated. The article is divided into two main parts. The first part presents the theory on information asymmetries and its consequences on energy efficiency focusing on the problems of moral hazard and adverse selection. Having established a theoretical framework to understand the agency barriers to energy efficiency, the second part evaluates the policies of the European Union on energy efficiency. The BEER finds that problems of moral hazard and adverse selection indeed can help explain the seemingly low levels of energy. In both presented models the cost to the principal from implementing high energy efficiency outcome is increased with the informational asymmetries. The theory reveals two implications to policies on energy efficiency. First, the development of measures to enable contractual parties to base remuneration on energy performance must be enhanced, and second, the information on technologies and the education of consumers and installers on energy efficiency must be increased. This could be complemented with certification of installers and energy efficiency advisors to enable consumers to select good agents. Finally, it is found that the preferred EU policy instrument on energy efficiency, so far, seems to be the use of minimum requirements. Less used in EU legislation is the use of measuring and verification as well as the use of certifications. Therefore, it is concluded that the EU should consider an increased use of these instruments, and in particular focus on a further development of standards on measurability and verification as well as an increased focus on education of consumers as well as installers and advisors on energy efficiency.

The Relationship between Energy and Socio-Economic Development in the Southern and Eastern Mediterranean. MEDPRO Technical Report No. 27/February 2013

This report aims to identify, explain and detail the links and interactions in southern and eastern Mediterranean countries (SEMCs) between energy supply and demand and socio-economic development, as well as the potential role of energy supply and demand policies on both. Another related aim is to identify and analyse, in a quantitative and qualitative way, the changing role of energy (both demand and supply) in southern Mediterranean economies, focusing on its positive and negative impact on socio-economic development. This report investigates in particular: o The most important channels through which resource wealth can contribute to or hamper economic and social development in the analysed region; o Mechanisms and channels of relations between energy supply and demand policies and economic and social development. The burdens of energy subsidies and ‘oil syndrome’ are of particular relevance for the region. An integrated socio-economic development and energy policy scenario approach showing the potential benefits and synergies within countries and the region is developed in the final part of the report.

Energy Efficiency: Trends and Perspectives in the Southern Mediterranean. MEDPRO Technical Report No. 21/December 2012

This paper has two objectives. First, it attempts to establish the potential of policies on energy efficiency and energy demand-side management in the southern Mediterranean region. Second, by examining past trends in energy intensity and trends up to 2030, it analyses the prospects and costs of such policies, compared with expected developments in the price of energy resources. Based on both analyses (MEDPRO WP4) and on prospects for growth (MEDPRO WP8), it seems that energy intensity in the Mediterranean should fall perceptibly by approximately 13% in the next 20 years. But given the programmed energy mix, this will not limit emissions of CO2, which are likely to increase by more than 90%. The paper first presents the rationale for demand-side management (DSM) policies. After a general discussion of concepts, it tackles the question of instruments and measures for implementing such policies, before posing the question of the cost-efficiency approach for monitoring the measures the authorities introduce. Secondly, the paper assesses energy consumption and energy efficiency in the countries of the southern Mediterranean and the ways in which their main economic sectors have changed in recent decades. The third section outlines the demand management measures introduced and, taking Tunisia and Egypt as examples, estimates the cost of such policies. The fourth and last section offers a forecast analysis of energy consumption in the Mediterranean up to 2030, highlighting probable trends in terms of final consumption, energy intensity, energy mix and emissions of CO2. The section concludes with estimates in terms of cost, comparing objectives for lower intensity, results in terms of resource savings and the types of costs this approach represents.

Consensus, contradiction, and conciliation of interests: the geo-economics of the Energy Union. EPC Policy Brief, 8 July 2015

European Union energy policy calls for nothing less than a profound transformation of the EU's energy system: by 2050 decarbonised electricity generation with 80-95% fewer greenhouse gas emissions, increased use of renewables, more energy efficiency, a functioning energy market and increased security of supply are to be achieved. Different EU policies (e.g., EU climate and energy package for 2020) are intended to create the political and regulatory framework for this transformation. The sectorial dynamics resulting from these EU policies already affect the systems of electricity generation, transportation and storage in Europe, and the more effective the implementation of new measures the more the structure of Europe's power system will change in the years to come. Recent initiatives such as the 2030 climate/energy package and the Energy Union are supposed to keep this dynamic up. Setting new EU targets, however, is not necessarily the same as meeting them. The impact of EU energy policy is likely to have considerable geo-economic implications for individual member states: with increasing market integration come new competitors; coal and gas power plants face new renewable challengers domestically and abroad; and diversification towards new suppliers will result in new trade routes, entry points and infrastructure. Where these implications are at odds with powerful national interests, any member state may point to Article 194, 2 of the Lisbon Treaty and argue that the EU's energy policy agenda interferes with its given right to determine the conditions for exploiting its energy resources, the choice between different energy sources and the general structure of its energy supply. The implementation of new policy initiatives therefore involves intense negotiations to conciliate contradicting interests, something that traditionally has been far from easy to achieve. In areas where this process runs into difficulties, the transfer of sovereignty to the European level is usually to be found amongst the suggested solutions. Pooling sovereignty on a new level, however, does not automatically result in a consensus, i.e., conciliate contradicting interests. Rather than focussing on the right level of decision making, European policy makers need to face the (inconvenient truth of) geo-economical frictions within the Union that make it difficult to come to an arrangement. The reminder of this text explains these latter, more structural and sector-related challenges for European energy policy in more detail, and develops some concrete steps towards a political and regulatory framework necessary to overcome them.

Energy-efficient commercial buildings : the range of possible solutions and their conceptual differences /

"Work Performed Under Contract No. EG-77-C-01-4042."

Alternative transportation fuels - financing issues. Options for financing alternative fuel vehicle fleets and infrastructure.

Urban Consortium Energy Task Force