Mobile Energy Sources Research Articles

Charging Schemes for Plug-In Hybrid Electric Vehicles in Smart Grid: A Survey

Plug-in hybrid electric vehicles (PHEVs) have emerged as an important tool in reducing greenhouse gas emissions, due to their lower dependency on fossil fuel. Since, for cost efficiency, PHEVs have a limited battery capacity, they must be recharged often and especially after trips. Thus, efficient battery charging plays an important role on the success of PHEVs commercial adoption. This paper surveys the state-of-the-art of existing PHEV battery charging schemes. We classify these schemes into four classes, namely, uncontrolled , indirectly controlled , smart , and bidirectional charging, and review various existing techniques within each class. For uncontrolled charging, existing studies focus on evaluating the impact of adding variable charging load on the smart grid. Various indirectly controlled charging schemes have been proposed to control energy prices, in order to indirectly influence the charging operations. Smart charging schemes can directly control a rich set of charging parameters to achieve various performance objectives, such as minimizing power loss, maximizing operator’s profit, ensuring fairness, and so on. Finally, bidirectional charging allows a PHEV to discharge energy into smart grid, such that the vehicle can act as a mobile energy source to further stabilize the grid, which is partially supplied by intermittent renewable energy sources. This survey provides a comprehensive one-stop introductory reference to quickly learn about the key features and technical challenges, addressed by existing PHEV battery charging schemes in smart grid.

Physiological investigation of heatable fabrics

On the market there are various heatable fabrics with a mobile energy source and a heating power of approximately 10 watts. Examples for heatable fabrics are multilayer outdoor fabrics (pants and jackets), one layer fabrics (jackets, vests), underwear (shirts and paints), gloves, socks and shoes and accessories like a kidney belt. Up to now heatable textile fabrics are in the focus of research activities but have not been a large market. The reasons for this are several: technical problems during the life time, unfavourable system design, usage restriction caused by low life of storage battery or problems by cleaning and washing. The German research project 17708BG has the aim to investigate the clothing physiological aspects of heatable fabrics and the comfort of such fabrics.

Linear Programming-Based Optimization for Robust Data Modeling in a Distributed Sensing Platform

Creating accurate data models describing the dynamics of physical phenomena in time and space is important in optimized control and decision making. Models highlight various trends and patterns. However, producing accurate models is challenging as different errors are introduced by sampling platforms with limited resources, e.g., insufficient sampling rates, data loss due to buffer overwriting, reduced communication bandwidth, and long communication delays. Furthermore, the dynamics of the environment, like mobile energy sources and sinks, might further increase errors as resources must be shared between the sampling and communication activities. This paper presents a procedure to systematically construct robust data models using samples acquired through a grid network of embedded sensing devices with limited resources, like bandwidth and buffer memory. Models are in the form of ordinary differential equations. The procedure constructs local data models by lumping state variables. Local models are then collected centrally to produce global models. The proposed modeling scheme uses a linear programming formulation to compute the lumping level at each node, and the parameters of the networked sensing platform, i.e., best data communication paths and bandwidths. Two algorithms are described to predict the trajectories of mobile energy sources/sinks as predictions can further reduce data loss and delays during communication. The computed parameters and trajectory predictions are used to configure the local decision making routines of the networked sampling nodes. Even though the procedure can be used to model a broader set of phenomena, experiments discuss the effectiveness of the method for thermal modeling of ULTRASPARC Niagara T1 architecture. Experiments show that the presented method reduces the overall error between 58.29% and 76.91% with an average of 68.87%, and communication delay between -11.49% and 57.62% with an average of 21.85%.

500W급 마이크로 가스터빈 발전기 회전체-베어링부의 단열 및 냉각 성능에 대한 실험적 연구

) ABSTRACT Development of long-term mobile energy sources for mobile robots or small-sized unmanned vehicles are actively increasing. The micro gas turbine generator (MTG) is a good candidate for this purpose because it has both of high energy density and high power density, and 500W class MTG is under development. The designed MTG can be divided into 2 main parts. One part consists of motor/ generator and compressor, and the other one consists of combustor, recuperator and turbine. 500W class MTG is designed to operate at ultra-high speed of 400,000 rpm in high turbine temperature over 700 ℃ to improve the efficiency. Because the magnetism of NdFeB permanent magnet for the motor/generator could be degraded if the temperature is over 150-200 ℃, MTG needs the thermal insulation to block the heat transfer from combustor/turbine side to motor/generator side. Moreover, the motor/generator is allocated to get the cooling effect from the rapid air flow by the compressor. This study presents the experimental results to verify whether the thermal insulator and air flow are effective enough to keep the motor/generator part in the low temperature less than 100 ℃. From the motoring test by using the high temperature test rig, it was confirmed that the motor/generator part could maintain the temperature less than 50 ℃ under the condition of 1.0 bar compressed air.

초고속 회전체용 공기 포일 베어링의 동특성 계수 측정을 위한 전자석 가진장치에 관한 연구

Recently the requirement of long-term mobile energy source for mobile robot or small-sized unmanned vehicle is highly increased, and the micro turbine generator(MTG) which is known to have high energy and power density is under development. MTG is designed to have air foil bearing and high speed rotor of which operating speed is 400,000rpm. In the development stage of high speed rotor and bearing, stability analysis for the full operational speed range is essential and the dynamic coefficients such as stiffness and damping coefficients of bearing depending on the rotational speed are required for that. Although perturbation method is usually used to identify the dynamic coefficients, it’s not easy to give the perturbation to the high speed rotating rotor. In this study, we present the dynamic coefficients measurement system for air foil bearing which consists of electromagnets, gap sensors, high speed motor and controller. This measurement system can exert the sine sweep force to the rotor-bearing, measure the displacement of rotor and get FRF(Frequency response function) of rotor-bearing. The least square estimation method is applied to identify the dynamic coefficients of bearing from the measured frequency response at the different rpm and the identified dynamic coefficients for the wide rotational speed range are presented.

Potassium (K + ) gradients serve as a mobile energy source in plant vascular tissues

The essential mineral nutrient potassium (K(+)) is the most important inorganic cation for plants and is recognized as a limiting factor for crop yield and quality. Nonetheless, it is only partially understood how K(+) contributes to plant productivity. K(+) is used as a major active solute to maintain turgor and to drive irreversible and reversible changes in cell volume. K(+) also plays an important role in numerous metabolic processes, for example, by serving as an essential cofactor of enzymes. Here, we provide evidence for an additional, previously unrecognized role of K(+) in plant growth. By combining diverse experimental approaches with computational cell simulation, we show that K(+) circulating in the phloem serves as a decentralized energy storage that can be used to overcome local energy limitations. Posttranslational modification of the phloem-expressed Arabidopsis K(+) channel AKT2 taps this "potassium battery," which then efficiently assists the plasma membrane H(+)-ATPase in energizing the transmembrane phloem (re)loading processes.

Aspects of delayed harvest of ‘Hass’ avocado (Persea americanaMill.) fruit in a cool subtropical climate. I. Fruit lipid and fatty acid accumulation

SummaryIn the cool, mesic, subtropical Natal midlands, where delayed harvesting of ‘Hass’ avocado fruit was practised, fruit lipid levels on a dry-mass basis peaked in September 1991 and August 1992 at the cooler site and October 1991 and September 1992 at the warmer site. In subsequent months lipid levels decreased at the warmer site. These observations suggest that under the experimental conditions, late hanging into the following season was not strongly detrimental to the following crop and may even be beneficial if fruit lipids are a partially mobile energy source, which may be utilized during periods of peak demand such as flowering, fruit set and shoot flushing. Fatty acid levels, dominated by the monounsaturated oleic acid, did not vary significantly with late hanging, and were very similar in the two sites in the cool Natal midlands. However, compared with fruit harvested in late August in the north-eastern Transvaal, total monounsaturated fatty acid levels were some 10% higher. These findings are discussed with respect to the health aspects of the avocado. Attempts at modelling monounsaturated fatty acid levels were unsuccessful as levels differed significantly in different months.

Metal Processing Control with Mobile Energy Sources

Systems with mobile energy sources are mathematically described. The basic properties of such systems are defined. The specifics of their optimization are analyzed; the optimal shape of the mobile source must be piecewise continuous. Methods are described for computing the parameters of mobile energy sources for various heating and temperature field maintenance processes. Choice of the source shape for the zonal annealing process is described. Details of the widely used energy source control system “Luch-O”are given. Ways to control the source power and motion speed from signals of the temperature field sensor are described where by “Skapir-1”, a new type of scanning pyrometer is used.