Electric Transportation Systems Research Articles

Remarkable CO2 Reduction of the Fixed Point Fishing Plug-in Hybrid Boat

It is quantitatively shown that this fishing system using a plug-in hybrid fishing boat (PHEB) provides an outstanding CO₂ reduction performance of more than 80 % compared with the simple diesel engine operation. This research has been conducted at the fishing area around a detached fishing island, Nushima, Japan. Based on the actual fuel consumption patterns of fishing by the fishermen, the quantitative analysis of daily fuel consumption was performed. The remarkable reduction of oil consumption is due to the high efficiency of the electric motor and the idling stop function during fixed fishing operation. The population of Nushima is 500 and 162 fishing boats are in daily operation. Among them, 117 boats (72 %) are working daily as a kind of fixed point fishing. When the access velocity and the return velocity of 30 minutes totally is decided, the daily fuel consumption by fixed position fishing is determined. It is also determined based on the actual fishing data that fixed point fishing is 8 hours daily in average. Using the CO₂ reduction result of 80 % in this study for the fixed point fishing operation, it is expected that 468 kL (20 L X 117 boats X 250 days X 0.8) of the fuel and 1,220 ton-CO₂ can be reduced annually. In Japan, about such 50,000 boats are fishing. So even in Japan, the total amount of CO₂ reduction expected can reach 61,000 tons annually. This research has been conducted as part of the newly developed S2G two-way electricity transportation system (from ship to grid and from grid to ship) using the PHEB to prove the effective use of renewable energy for ship propulsion and successful reduction of CO₂ emission under the research program of Empirical study of the independence distribution energy system technology based on DC technology in a detached island and a fishing village financed by the Ministry of Environment of Japan subsidy 2014-2016.

Adaptive systems of traction power supply

At present, a great variety of traction power supply systems (TPSSs) are being used, planned, and developed for the future. This is because of the specifics of the electric transport system, as well as scientific and technological progress. The variety of TPSSs became possible as a result of the development of power semiconductors for transforming electricity parameters, as well as due to significant improvements in switching and power equipment. On the whole, control over their regimes of operation and the provision of desired quality parameters of electricity on electric rolling stock (ERS) bow collectors are still problems to be solved in traction power supply systems. Quality parameters for electricity are given in detail in different standards, specifications, rules for design and operation, and GOSTs (State Standards), but optimization of operating regimes of transport systems has not been considered. ”Regime optimization” may refer to (1) the voltage of ERS collectors and its deviations and oscillations affecting travel speed and traction characteristics, (2) consumption of electricity during transportation in conducting mains and load-bearing members of the system, and (3) use of electric braking energy. To ensure optimization of operating regimes, adaptive traction power supply systems are necessary, which should be understood as an uninterrupted evolution of traction power supply for energy consumption by trains. In this paper, an adaptive traction power supply system with voltage converters in the intersubstation zone is analyzed. The circuits and characteristics of the system’s elements are shown, and its electrical quantities are determined.

Transformation of the Urban Electric Transport System when Using Autonomous Energy Sources

In paper, the problems of shared use of photovoltaic energy sources and energy storage devices for the implementation of sustainable energy-efficient operation of the power supply system urban electric transport are considered. The main attention is paid to a solution of the unevenness power curve problem of traction power supply system under the natural technological development of urban electric transport system. The conceptual solution of power supply structure on the basis of used capacities, with their substitution by the rational share of autonomous power sources capacities, is proposed.

Study on Multidimensional Intelligence for Realizing Seamless Power Supply between the Port and Ship

The dissertation discussed marine generator synchronous technology, as well as, intelligent on-shore controlling circulation current by means of using reactor to limit circulation current, both of which may realize seamless connection between ship electrical system and shore power; and also demonstrated intelligent FCL all-controlling power electronic device GTO (Gate Turn-off Thyristor) blocking and conducting, that can ensure the rapidity of connecting and disconnecting reactor and notable current limit effect. The dissertation proves the effect of seamless power supply between the port and ship, as a result of simulation model of intelligent FCL on-shore controlling circulation current. And intelligently dealing with electricity bills processing, as well as seamless power supply, which realize marine energy conservation and low-carbon emissions reduction in the port, can ensure to realize uninterruptable power on-shore connection, and at the same time promote the development of intelligent port.

A Compact Error Management Algorithm to Minimize False-Alarm Rate of Motor/Generator Faults in (Hybrid) Electric Vehicles

This paper addresses an emerging reliability and safety requirement for more electric transportation systems by proposing an on-board diagnostics plug-in tool. For this purpose, a compact diagnostic algorithm is presented using an advanced speed feedback error management technique for traction motor and generator faults which is one of the most critical parts of the vehicle powertrain. The speed measurement accuracy can be degraded for various reasons such as: sensor issues, vehicle vibration, hardware tolerances, and environmental impacts like temperature, moisture, and electromagnetic interferences. Although the speed feedback errors within an acceptable level can be tolerated by most of the drive systems, the accuracy of speed measurement is critical for the reliability of fault diagnosis. The major reason behind this fact is the frequency of fault signature in the spectrum is primarily determined using the motor speed. It is shown how the reliability of a motor fault diagnosis decision can significantly be improved under erroneous speed feedback conditions by using the developed effective error localization and coarse-to-fine detection technique. The proposed scheme is implemented through effective strategies to minimize computational complexity and memory occupancy in every step of signal processing according to manufacturers' strict cost limitation.

Optimizing the Energy Efficiency of Electric Transportation Systems Operation Using a Genetic Algorithm

Energy consumption of a rail transit system depends on many parameters. One of the most effective methods of reducing energy consumption in a rail transit system is optimizing the speed profile of the trains along the route. A genetic algorithm (GA) based approach is proposed to search for the optimal train speed trajectory, given a journey time constraint, and its effectiveness is shown by simulation results. The proposed approach includes realistic system modeling using an integrated electromechanical simulation model to calculate train energy consumption and travelling time under different operating conditions, inter-station distances, track profiles.

Planning Restoration of Vital Infrastructure Services Following Hurricane Sandy: Lessons Learned for Energy and Transportation

Hurricane Sandy arrived on October 29, 2012 with enormous adverse impacts on one of the largest metropolitan areas in the world, the New York region, including its electric power and transportation systems that disrupted the social and economic fabric of a wide geographic area. How these services were restored is an important basis for proactively designing robust public services not only in areas affected by Hurricane Sandy but also for many similar areas and events worldwide. Recovery rates are one important indicator of consequences of disaster. Selected physical and social measures of recovery are analyzed for New York City electricity and rail transit services following Hurricane Sandy to capture the ability of these services to be restored over various time periods, and to illustrate the use of indicators of restoration for infrastructure service resilience analyses for disaster management and planning. Electricity impacts and recovery are presented in user-oriented terms as the ratio of customers affected and restored to both customers without service and total customers served in the period following the hurricane. Results showed that restoration rates varied among the boroughs of NYC potentially reflecting differences in infrastructure resilience and exposure conditions. Rail transit impacts and recovery were analyzed in terms of both the restoration of the two dozen subway lines as a physical measure and ridership by station as a user or social measure. Line recovery analyses showed that within about a couple of weeks of the storm almost 80 percent of the lines were fully restored, almost 20 percent were partially restored, and complete suspensions were rare indicating a high degree of restoration capacity. Ridership measured at stations was compared to levels and rates of change over various time periods around the storm period, as well as from the previous year. High correlations in ridership between single days before and after the storm indicated little redistribution of ridership across stations between those time periods, however, rates of change indicated about a 14–16 percent decline in ridership system-wide within a two week period following the storm relative to the same time period the year before, recovering later, possibly reflecting slower rates of social recovery relative to the recovery of the physical transit systems. A longer period of service quality effects occurred due to lingering equipment damage potentially attributed for example to water damage and corrosion from saltwater. These findings point to the importance of recovery time as at least an initial guide to ways of systematizing service restoration measures and are a foundation for physical, social, and institutional adaptation strategies some of which are already being put in place. Larger considerations remain however in interpreting recovery restoration goals and who decides them.

Research on Intelligent FCL to Realize Seamless Power Supply between the Port and Ship for Energy Conservation and Emissions Reduction

The dissertation establishes simulation model of intelligent FCL on-shore controlling circulation current, which can realize effective control of largest ring current when the shore power is connected to ship electrical system, and can further complete seamless connection between ship and shore power, so as to realize the ship energy conservation and emissions reduction in port. And also demonstrates paralleling on-shore control on-shore power grid on the intelligent platform into the ship`s power grid of generators, and FCL uses reactor to control inrush circulation current, which uses finite circulation current to complete the average voltage and automatic synchronization of the generator, being capable of taking the on-shore power into the generator power grid and exiting from that; moreover, parallels intelligent on-shore controlling marine generators of the power grid into on-shore power grid. Basically unchanging the ship power station, realizing uninterruptable power on-shore connection, at the same time realizing the ship electricity pricing such as wisdom.

Improved Electrochemical Performances of Mesoporous Carbon-Sulfur Composites with Lithium Polysulfides Added Electrolyte

Lithium-Sulfur batteries have been intensively studied as a power source of the electric transportation and energy storage system for renewable energy due to their high theoretical capacity of 1675 mAh g-1 and relatively inexpensive raw materials than commercial lithium ion batteries.1 To introduce lithium sulfur batteries to commercial market, there are some drawbacks to be solved. The major problems of lithium sulfur batteries are low active material utilization, severe capacity decay and low coulombic efficiency. Several successive approaches have been adopted to develop practical lithium sulfur batteries either by selecting electrolyte more adequate than conventional carbonate solutions, such as 1,3 dioxolane (DOL), dimethyl ether (DME), and tetraethylene glycol dimethyl ether (TEGDME), or by the addition of soluble polysulfides.2–7 On sulfur cathode side, modification of morphology of active materials have been studied by mixing conductive carbons with sulfur particles, encapsulating sulfur into porous carbon matrix and conductive polymer coating on the surface of active materials. These approaches have led to the development of lithium–sulfur battery with improved cycle life and rate capability. However these progresses of lithium sulfur batteries have not satisfied requirements of commercialization. These lithium sulfur batteries are still suffered from the problem of the solubility of the polysulfides. Recentely, Tarascon and co-workers8 and Zhang and Read reported noticeable achievement by addition soluble lithium polysulfide into the electrolyte.7 In this work, we studied the electrochemical and physical effect of the Li2S8 polysulfide additive diminishing the dissolution of the sulfur cathode and small participation in redox reaction as a dissolved cathode.7, 8 We demonstrated intentionally dissolved Li2S8 polysulfides in the electrolyte suppress polysulfide dissolution from the sulfur cathode by controlling its concentration according to Le Chatelier’s principle. Li2S8 polysulfide additives was deposited on the cathode as sulfur on charging to compensate eventual capacity losses that result from partial cathode dissolution during discharge.2– 8 Fig. 1 shows the cycling performance and efficiency of a mesoporous carbon-sulfur electrode in a lithium cell using the TEGDME–LiCF3SO3 electrolyte with addition of 5 wt% Li2S8. The cell cycled at 20 ℃ shows a small initial capacity decay, that is, from 1650 to 1500 mAh g-1s, followed by a stable trend with an acceptable, minor capacity decay, that is, from 1500 to about 1200 mAh g-1 Sover 50 cycles, with a coulombic efficiency approaching 95%.

Electric Vehicle Magnetic Fields and Their Biological Relevance

Public expectations to move towards electric mobility are driven by various factors such as climate policy,high oil prices, and pollutantsdue to internal combustion engines .On the other hand, there is exten sive public concern about the possible adverse health effects of electromagnetic fields (EMF) generated by electric vehicles .As electrical power and power electronics systems become more prevalent in transportation, the need for examining biological relev ance of such systems becomes ever more important. In particular, it is necessary to pay special attention to magnetic fields (MF), because biological studies suggest that magnetic rather than electric component could be biologically effective. In this paper we present a review of observed EMF on electric vehicles (EV) and possible biological effects together with our research on measurements and analysis of magnetic fields encountered onboard public DC - and AC-powered vehicles. Mautomotive magnetic field magnitudes varied from a few �oT to 120 �oT. For members of the general public, this range of exposures in personal scale electric transportation systems is comparable in magnitude to exposures from other commonly encountered sources. However, electricvehicles exposures aretotally different from common power line exposures; they are characterized by the complex frequency content

AC-Induced Corrosion of Underground Steel Pipelines. Faradaic Rectification under Cathodic Protection: I. Theoretical Approach with Negligible Electrolyte Resistance

Underground pipelines protected with a thick coating and by cathodic polarisation may suffer a serious external corrosion damage in the presence of stray alternating current (AC) voltage induced by high voltage industrial electric transport system, such as power lines or electrified railroads. The origin of the corrosion enhancement comes from the nonlinearity of the currentpotential characteristics of the metal-soil interface. In this paper, we will theoretically evaluate the increase of the corrosion current density and the potential shift induced by a high amplitude AC signal to models of corroding systems: anodic polarisation curves obeying an exponential law with respect to the potential, and cathodic process under the mixed activation-diffusion kinetics. The originality of the present work lies in the use of a relatively small number of dimensionless variables to describe the faradaic rectification for the corrosion potential shift and the corrosion current enhancement. In this article, the effect of the electrolyte resistance was neglected.

The Extraction of Feature Signal of All-electric Ship Electric Power System Based on Wavelet Analysis

The unit capacity of propulsion motor is greater than that of generator in all-electric ship electric system, in this high power load changes under the impact of random overload, the generator is extremely easy to have the fault causing system crashes. In this paper, a mathematical model of all-electric ship power system was established, and wavelet analysis was used to extract the feature of heavy load of power grid fault condition based on MATLAB. The simulation results prove that the simulating model of All Electric Ship Power System (AESPS) is reasonable, and by using the method wavelet analysis the feature information can be effectively extracted, which provides the basis for fault diagnosis. Keyword: Electric propelling ship, Power system, Digital simulation, Heavy load, Wavelet transform, Feature extraction

Modelling and Assessing Energy Performance of an Urban Transport System with Electric Drives

Energy conservation is one of the key priorities of sustainable development strategy. Transport systems are responsible for about one third of energy consumption. As result, the identification of solutions to reduce energy consumption in these systems is essential for the implementation of the sustainable development strategies. The present work is dedicated to identifying the possibilities for a reduction in the consumption of electric energy in electric urban public transport systems, using the audit of their electricity system. After justifying the importance of these concerns, a mathematical model of the electrical energy balance of the electric urban public transport system and its components is presented. The analysis is applied to determine the losses in the system components and useful energy, based on the evaluation and energy consumption measurements. The measurements to reduce energy losses are identified and characterized under technical and economic aspect, optimal electrical energy balances being done on this basis.

Simulation of an electric transportation system at The Ohio State University

We use longitudinal dynamics and simulation models to study the feasibility of deploying electric buses in place of conventional ones. The longitudinal dynamics model estimates energy use by an electric bus operating on different lines consisting of a mixture of urban and suburban driving. The simulation model is used to study the effect of the type and number of chargers deployed and the queuing policy used on queuing and charging times when buses must recharge their batteries. We use a case study based on the bus service operated on The Ohio State University campus and focus on six of the seven lines which operate around the center of campus. We demonstrate that all 22 of the buses on these lines can be made electric and that one 500kW or two 250kW chargers are sufficient to maintain reasonable service frequencies.

The Optimal System Design of the Online Electric Vehicle Utilizing Wireless Power Transmission Technology

The Online Electric Vehicle (OLEV) is an innovative electric transportation system developed by the Korea Advanced Institute of Science and Technology (KAIST), Daejon, Korea, which remotely picks up electricity from power transmitters buried underground. Unlike a conventional electric vehicle that requires significant recharging downtime, the battery in the OLEV can be charged while the vehicle is in motion. Selected as one of “the 50 Best Innovations of 2010” by TIME Magazine, the OLEV is considered as a potential solution for the next-generation electric public transportation system in South Korea. The prototype of the OLEV has been developed, and the commercialization process is now in progress. One of the main tasks to achieve the successful commercialization of the system is to determine economically how to allocate the power transmitters on the given routes and how to evaluate the right battery capacity for the vehicle. The allocation of the power transmitters and the size of the battery capacity directly affect the initial infrastructure cost. In this paper, we first introduce the system design issues of the mass transportation system operating with OLEV. We then present a mathematical model and an optimization method to allocate economically the power transmitters and to determine the battery capacity of the OLEV-based mass transportation system. The particle swarm optimization (PSO) algorithm is used as the solution method for the optimization problem. Numerical problems with sensitivity analysis are presented to show the validity of the mathematical model and solution procedure.

Energy supply infrastructure LCA model for electric and hydrogen transportation systems

Many transportation environmental life cycle analyses neglect the contribution of the energy supply infrastructures. In alternative light duty vehicle technologies, it has been shown through case studies that this can be a relevant factor. However, no model that can generalise the evaluation of energy and emissions from construction, maintenance and decommissioning of such infrastructure to analyse different scenarios currently exists. A model is proposed, focussing on electricity and on hydrogen supply through centralised steam methane reforming (H2(a)) and on-site electrolysis (H2(b)). The model outputs are in gCO2eq/MJ and MJeq/MJ of the final energy. Model main inputs are the region's electricity mix, the annual distance driven, supply chain losses and the number of vehicles per station or chargers. The evaluation of the number of vehicles served per each charger/station as a function of annual distance driven is presented. The uncertainty is estimated by using the pedigree matrix, impact uncertainty and literature estimates. The model shows consistency in the results and uncertainty range. Charging policies that minimise the electricity infrastructure burden should incentivise approximately 37% of normal charging. H2(a) pipeline lifetime should be extended. Efforts in the electrolyser should be undertaken to approximate the ratio of vehicles per station with a conventional one.

Time and frequency characterization of radiated disturbance in telecommunication bands due to pantograph arcing

Radiated emissions from arcing between pantograph and overhead wire in electrical transportation systems extend up to the frequency bands currently used for telecommunications and may therefore affect quality of telecommunication systems. The paper investigates on the time and frequency characteristics of the disturbances. Transient amplitude, rise time and pulse duration were measured in the time domain to obtain the associated empirical distributions; the power spectrum and the frequency content were calculated in the bands of interest; finally a time–frequency representation has been used to observe the evolution of the power spectrum over time and determine the location of the main contributions. Measurement of the channel power has also been carried out to investigate on the relevance of the disturbance power for some bands of interest for telecommunication services.

Transformerless Three-Level DC-DC Buck Converter with a High Step-Down Conversion Ratio

For high power high step-down dc-dc conversion applications, conventional three-level dc-dc converters are subject to extreme duty cycles or increased volume and cost due to the use of transformers. In this paper, a transformerless three-level dc-dc buck converter with a high step-down conversion ratio is proposed. The converter comprises two asymmetrical half bridges, which are of the neutral point clamped structures. Therefore, the output pulse voltage of the converter can be obtained in terms of the voltage difference between the two half bridges. In order to realize harmonious switching of the converter, a modulation strategy with capacitor voltages self balance is presented. According to the deduced output dc voltage function, transformerless operation without extreme duty cycles can be implemented. Experimental results from a 1kW prototype verify the validity of the proposed converter. It is suitable for ship electric power distribution systems.

Fast Evaluation Methods for Voltage Sags in Ship Electrical Power Systems

Induction motors are widely used in ship electrical power applications as they are frequently switched on into the supply system, consuming about 70% of the electrical energy generated. Voltage sag, which is produced by the starting current of induction motors, is one of the main causes of sensitive equipment dropout and, as such, must be considered in ship electrical system designs to comply with classification societies' rules. A simple and fast method that is able to estimate the expected magnitude of voltage sag disturbances and provide information about the effectiveness of the various mitigation methods is essential. This paper aims at presenting a faster evaluation method for voltage sags due to motor start-ups in ship electrical power systems. The performance of the proposed method is validated by measurements gathered from several motor starter designs in practical ship power applications using the Riemann-summation-principle-based evaluation method. The proposed method can provide engineers with useful information about the actual magnitude of sag disturbances as well as on the effectiveness of motor starters for ship electrical power applications, which will assist them in determining proper motor starter designs.

The Design and Implementation of Ship Electric Field Measurement System Based on MSP430

The ship electric field has become a new physical field which is widely concerned at home and abroad in recent years. For the research of ship electric field, one of the most effective methods is to measure it underwater. According to the analysis of ship electric field signal’s characteristics, the ship electric field measurement system based on MSP430F149 was designed and the key technologies of software and hardware were also presented in this paper. The results of experiment demonstrated that the system could effectively measure the ship electric field signal in a low SNR. Meanwhile, it has the advantages of low power consumption, high accuracy and credible.