Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xiii, 112 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 107-112).

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 97-99). Also available on the World Wide Web.

Range anxiety is a relatively new concept which is defined as the fear of running out of power when driving an electric vehicle. To decrease range anxiety you can increase the battery size or decrease the minimum state of charge, the least amount of power that can be left in the battery, or to expand the available fast charging infrastructure. But is that economical feasible or even technically possible in today’s society? In this project we have used a theoretical model for estimating range anxiety and have simulated the average electricity consumption using two different kinds of electric vehicles, to see how often they reach range anxiety according to a specific definition of range anxiety implemented in this model. The simulations were performed for different scenarios in order to evaluate the effect of different parameters on range anxiety. The result that we got were that range anxiety can be decreased with bigger batteries but to get range anxiety just a few times a year you have to use battery sizes which aren’t economical feasible today. Despite the shortcomings of todays electric vehicles there are promising new and future technologies such as better batteries which might help alleviate range anxiety for electric vehicle owner. The conclusion from this study is that in the present fleet of electric vehicles is in need of more charging stations and faster charging to get by the problem with range anxiety and having a chance to compete with gasoline and diesel vehicles.

Power-split hybrid-electric vehicles (HEVs) provide two power paths between the internal combustion (IC) engine and the driven wheels through gearing and electric machines (EMs) composing an electrically variable transmission (EVT). EVTs allow IC engine control such that rotational speed is independent of vehicle speed at all times. By breaking the rigid mechanical connection between the IC engine and the driven wheels, EVTs allow the IC engine to operate in the most efficient region of its characteristic brake specific fuel consumption (BSFC) map. If the most efficient IC engine operating point produces more power than is requested by the driver, the excess IC engine power can be stored in the energy storage system (ESS) and used later. Conversely, if the most efficient IC engine operating point does not meet the power request of the driver, the ESS delivers the difference to the wheels through the EMs. Therefore with an intelligent supervisory control strategy, power-split architectures can advantageously combine traditional series and parallel power paths. In the first part of this work, two different power-split HEV powertrains are compared using a two-term cost function and steady-state backward-looking simulation (BLS). BLS is used to find battery power management strategies that result in minimized fuel consumption over a user-defined drive-cycle. The supervisory control strategy design approach amounts to an exhaustive search over all kinematically admissible input operating points, leading to a minimized instantaneous cost function. While the approach provides a valuable comparison of two architectures, non-ideal engine speed fluctuations result. Therefore, in the second part of the work, two approaches for designing control strategies with refined IC engine speed transitions are investigated using high-fidelity forward-looking simulation (FLS). These two approaches include: i) smoothing the two-term cost function optimization results, and ii) introducing a three-term cost function. It is found that both achieve operable engine speed transitions, and result in fuel economy (FE) estimates which compare well to previous BLS results. It is further found that the three-term cost function finds more efficient operating points than the smoothed two-term cost function approach. From the investigations carried out in parts one and two of this work, a two-phase control strategy development process is suggested where control strategies are generated using efficient steady-state BLS models, and then further tested and verified in high-fidelity FLS models. In conclusion, the FLS results justify the efficacy of the two-phased process, suggesting rapid and effective development of implementable power-split HEV supervisory control strategies.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Dr. A. P. Meliopoulos; Committee Member: Dr. David Taylor; Committee Member: Dr. Ronald Harley; Committee Member: Dr. Shijie Deng. Part of the SMARTech Electronic Thesis and Dissertation Collection.

In many countries across the world, fossil fuels, especially petroleum, are the largest energy source for powering the socio-economic system and the transportation sector dominates the consumption of petroleum in these societies. As the petroleum price continuously climbs and the threat of global climate changes becomes more evident, the world is now facing critical challenges in reducing petroleum consumption and exploiting alternative energy sources. A massive adoption of plug-in electric vehicles (PEVs), especially battery electric vehicles (BEVs), offers a very promising approach to change the current energy consumption structure and diminish greenhouse gas emissions and other pollutants. Understanding how individual electric vehicle drivers behave subject to the technological restrictions and infrastructure availability and estimating the resulting aggregate supply-demand effects on urban transportation systems is not only critical to transportation infrastructure development, but also has determinant implications in environment and energy policy enactment. Driving PEVs inevitably changes individual’s travel and activity behaviors and calls for fundamental changes to the existing transportation network and travel demand modeling paradigms to accommodate changing cost structures, technological restrictions, and supply infrastructures. A prominent phenomenon is that all PEV drivers face a distance constraint on their driving range, given the unsatisfactory battery-charging efficiency and scarce battery-charging infrastructures in a long period of the foreseeable future. Incorporating this distance constraint and the resulting behavioral changes into transportation network equilibrium and travel demand models (static and/or dynamic) raises a series of important research questions. This dissertation focuses on analyzing the impact of a massive adoption of BEVs on urban transportation network flows. BEVs are entirely dependent on electricity and cannot go further once the battery is depleted. As a modeling requirement in its simplest form, a distance constraint should be imposed when analyzing and modeling individual behaviors and network congestions. With adding this simple constraint, this research work conceptualizes, formulates and solves mathematical programming models for a set of new BEV-based network routing and equilibrium problems. It is anticipated that the developed models and methods can be extensively used in a systematic way to analyze and evaluate a variety of system planning and policy scenarios in decision-making circumstances of BEV-related technology adoption and infrastructure development. / text

A transition to low speed vehicles (LSVs), a federally-designated class of vehicles smaller, lighter and slower (limited to maximum speeds between 20 and 25 mph) than conventional automobiles, for intra-city travel offers several advantages. Their smaller size provides roadway space for other modes such as cycling and reduces the amount of land dedicated to vehicles. Their lower maximum speeds are more compatible with operation in populated areas where cars traveling at 30 mph prove deadly for pedestrians and people biking, and their energy usage and emissions are less than conventional automobiles. Communities such as Lincoln, CA, Peachtree City, GA, and those in the South Bay Cities and Western Riverside Councils of Governments in California recognize the benefits of using LSVs and actively provide infrastructure and programs to support their use. Considering the advantages of LSVs, this dissertation demonstrates potential ways to transition to LSVs and seeks to answer a question considered key to their adoption as the means of motorized travel in the city: Could LSVs also offer a travel time advantage? The basis for this seemingly paradoxical question is the observation that because of their smaller size, lower weight, and slower speed, more space- and operationally-efficient intersections, such as LSV-scaled roundabouts, overpasses and interchanges, are possible within the existing right-of-way to replace signalized intersections. The hypothesis that LSVs can offer comparable or better travel time compared to conventional automobiles assumes the removal of intersection delay will allow LSVs to make-up for their slower speeds. The methodology to test the hypothesis uses dynamic traffic assignment to compare average system, corridor and origin to destination travel times for conventional automobiles and LSVs in a subnetwork of Austin, Texas during transition periods when both vehicles are permitted and when only LSVs may be used for intra-city motorized travel. The findings indicate LSVs can offer similar and in some cases better average travel times than those for conventional automobiles, especially for the LSV-only network. However, careful planning is required during the transition stages when both vehicle types are in operation to maintain acceptable travel times for both conventional automobiles and LSVs. / text

This work evaluates the impact of electric vehicle loads (EVs) on utility distribution secondary networks and determines the factors affecting the network voltage quality. The study is conducted using two actual distribution circuits, residential and mix residential and industrial circuits. The study reveals the following. A distant secondary network experiences a greater steady-state voltage drop than a nearby secondary network. Location of EV loads relative to the service transformer affects the secondary voltage more significantly. An EV load installed on a distant load node from a service transformer causes comparatively higher undervoltage condition (about 1.5%) than an EV on a nearby load node from the service transformer (about 0.75%). Increasing the size of EV charger increases the severity of an undervoltage condition. A 240V/30A EV charging station causes undervoltage condition to double compared to that of a 240V/16A EV charger. Also installing an EV load adjacent to the existing EV load customer approximately doubles the undervoltage condition at the EV load nodes. / text

Η παρούσα διπλωματική εργασία πραγματεύεται τη θεωρητική ανάλυση και προσομοίωση διάταξης φόρτισης ηλεκτροχημικών συσσωρευτών για ηλεκτροκίνητο όχημα καθώς και την κατασκευή της για την πειραματική απόδειξη της ορθής λειτουργίας της. / This thesis deals with the theoritical analysis and simulation of power supply for electric vehicle and the construction for experimental evidence for the proper functioning of the power supply.

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