Power Source Capacity Research Articles

Ensuring the sustainability of real-time embedded system under both QoS and Energy Constraints

Nowadays, wireless sensor networks (WSNs) are more and more used in applications such as environment monitoring, healthcare monitoring, etc...The challenge in sensor networks is to ensure the sustainability of the system by guaranteeing the required performance level. However, with the limited capacity of finite power sources and the need of guaranteeing a long lifetime of those systems, it is suitable to use energy harvesting which allows to supply low-power electronic systems by converting ambient energy into electric power. Hence, our study is concerned with the problem of soft periodic and aperiodic tasks scheduling in sensor nodes powered by energy harvesters. In this paper, we address this issue by proposing three energy-aware schedulers, namely BG-Green-RTO, BG-Green-BWP and Green-AWP which aim to improve the responsiveness of aperiodic tasks while still guaranteeing the execution of periodic tasks considering their timing and energy constraints. Such algorithms allow to gracefully cope with processing overload and energy starvation. Moreover, a simulation study permits to show their performance.

ENERGY HARVESTING TECHNIQUES IN WIRELESS SENSOR NETWORKS

Batteries are the main source of energy for low-power electronics such as micro-electro mechanical systems (MEMS), wireless sensor networks, embedded devices for remote sensing and control, etc. With the limited capacity of finite power sources and the need for supplying energy for the lifetime of a system/device there is a requirement for self-powered devices. Using conventional batteries is not always good design solution because batteries require human intervention to replace them (very often in hard-accessible and harsh-environmental conditions). Therefore, acquiring the electrical power, by using an alternative source of energy that is needed to operate these devices is a major concern. The process of extracting energy from the surrounding environment and converting it into consumable electrical energy is known as energy harvesting or power scavenging. The energy harvesting sources can be used to increase the lifetime and capability of the devices by either replacing or augmenting the battery usage. There are various forms of energy that can be scavenged, like solar, mechanical, thermal, and electromagnetic. Nowadays, there is a big interest in the field of research related to energy harvesting. This paper represents a survey for identifying the sources of energy harvesting and describes the basic operation of principles of the most common energy harvester. As first, we present, in short, the conversion principles of single energy source harvesting systems and point to their benefits and limitations in their usage. After that, hybrid structures of energy harvesters which simultaneously combine scavenged power from different ambient sources (solar, thermoelectric, electromagnetic), with aim to support higher load at the output, are considered.

Research and Application of Grid AGC Collaborative Realtime Control Method Based on Wind Power Forecast Deviation

New energy sources such as wind power are developing rapidly, which contributes to the green development of society and economy. However, wind power is a fluctuating power source with uncontrollable power. It is necessary to predict the power capacity of wind power generation and reasonably allocate the operation mode of thermal power units to realize the power grid’s absorption of wind power. By analyzing the influence of the wind power output prediction error on the grid area control error(ACE), the number of inputs of the thermal power unit’s automatic generation control(AGC) mode is dynamically adjusted in real time to meet the load adjustment rate required for the ACE change. The results show that this method can effectively improve the load regulation capacity of the power grid, improve the consumption capacity of wind power and other new energy sources, and ensure the stability of the power grid frequency.

Component Sizing of Parallel Hybrid Electric Vehicle Using Optimal Search Algorithm

In designing a parallel hybrid electric vehicle, it is essential to select the optimal capacity of power sources and the optimal gear ratio of the torque coupler. The capacity of the power sources and the gear ratio of the torque coupler should be optimized simultaneously. However, since this process is excessively time-consuming, previous studies have selected the gear ratio of the torque coupler and then selected the capacity of power source. However, this approach cannot guarantee global optimization. In this paper, a feasible region is defined to satisfy the required performance of vehicle such as maximum speed, hill-climbing. and feasible points are selected inside the feasible region. In the conventional technique, the global optimal solution is obtained by simulating all feasible points. In the optimization technique, optimal points are simulated within the feasible region using several optimal search algorithms, such as the golden section search algorithm and the hillclimbing search algorithm. And using these algorithms, the number of simulations is reduced and the capacity of the power source and the gear ratio of the torque coupler are optimized simultaneously. Finally, the validity of the component sizing results is verified by comparing the global optimal solution obtained by applying the conventional technique with the solution obtained by applying the proposed optimization technique.

Decentralized DC Microgrid Monitoring and Optimization via Primary Control Perturbations

We treat the emerging power systems with direct current (DC) MicroGrids, characterized with high penetration of power electronic converters. We rely on the power electronics to propose a decentralized solution for autonomous learning of and adaptation to the operating conditions of the DC Mirogrids; the goal is to eliminate the need to rely on an external communication system for such purpose. The solution works within the primary droop control loops and uses only local bus voltage measurements. Each controller is able to estimate (i) the generation capacities of power sources, (ii) the load demands, and (iii) the conductances of the distribution lines. To define a well-conditioned estimation problem, we employ decentralized strategy where the primary droop controllers temporarily switch between operating points in a coordinated manner, following amplitude-modulated training sequences. We study the use of the estimator in a decentralized solution of the Optimal Economic Dispatch problem. The evaluations confirm the usefulness of the proposed solution for autonomous MicroGrid operation.

Optimized Planning of Power Source Capacity in Microgrid, Considering Combinations of Energy Storage Devices

Since renewable energy resource is universally accepted as a promising method to solve the global energy problem, optimal planning and utilization of various distributed generators (DG) and energy storage (ES) devices deserve special concern. ES devices possess various characteristics in power density, energy density, response speed (switching speed) and lifetime. Besides, as different load types have various requirements on power supply reliability according to their importance, coordinated planning with consideration of reasonable matching between power source and load can efficiently improve power supply reliability and economic efficiency via a customized power supply and compensation strategy. This paper focuses on optimization of power source capacity in microgrid and a coordinated planning strategy is proposed with integrated consideration of characteristics of DG, ES and load. An index named additional compensation ratio (ACR) for balancing economic efficiency and reliability is proposed and considered in the strategy. The objective function which aims to minimize life cycle cost (LCC) is established considering economic efficiency, reliability and environmental conservation. The proposed planning strategy and optimizing model is calculated and verified through case study of an autonomy microgrid.

중형저상버스 병렬형 하이브리드화를 위한 동력전달계 용량매칭

그 동안 하이브리드 버스에 대한 연구로 플러그인 하이브리드, 직렬형, 병렬형 하이브리드 등에 대한 연구가 많이 진행되어져 왔다. 하지만 연구가 진행된 대부분의 차량들은 대형 버스이며 현재 국내에는 중형저상버스에 대한 연구는 전무한 실정이다. 또한 중형저상버스의 하이브리드화에 대한 연구 역시 미미한 실정이다. 본 논문은 MATLAB을 이용한 시뮬레이션을 통해 디젤 중형저상버스의 연비 평가를 수행하였으며, 이를 하이브리드화하였을 경우에 대한 최적의 용량 조합과 기어비를 제시하고 내연기관 시뮬레이션 연비 결과와 비교 분석하였다. 하이브리드화를 위한 구조로 전륜과 후륜이 독립적으로 동력을 전달하는 병렬형 하이브리드 시스템을 선택하였다. 동력원 용량 설계를 위해 목표 성능을 만족하는 요구파워를 계산하여 적용 가능한 동력원 용량 영역을 설계하였다. 설계 영역을 만족하는 각 단품들의 용량은 스케일링하여 구성하였으며, 엔진과 모터에 대한 동력 전달계의 용량 설계 알고리즘을 제시하고 동적 계획법을 이용하여 최적화를 수행하였다. 최종적으로 본 연구를 통해 내연기관 차량인 중형저상버스를 하이브리드화하였을 경우에 대한 연비 향상률과 최적의 동력원 용량, 기어비를 제시하였다. Most studies on hybrid buses are on large-sized buses and not mid-sized low-floor buses. This study uses MATLAB simulation to evaluate the fuel efficiency of such buses powered by diesel. Based on the results, a hybrid electric vehicle system is recommended for the best combination of power and gear ratio. A parallel hybrid system was selected for the hybridization, which transmits front and rear wheel power independently. The necessary power to satisfy the target performance was calculated, and the applicable capacity area was designed. Dynamic programing was used to create and optimize a component sizing algorithm, which was used to scale the capacity of each component of the power source to satisfy the design criteria. The fuel efficiency rate, optimum power source capacity, and gear ratio can be improved by converting a conventional bus into a parallel hybrid bus.

CMCS: a cross-layer mobility-aware MAC protocol for cognitive radio sensor networks

Cognitive radio sensor networks (CRSNs) are multi-channel-capable networks that inherit some of the challenges of traditional wireless sensor networks (WSNs), such as limited power source and hardware capacity. In several CRSN applications, such as surveillance and intelligent transportation systems, node mobility is a typical assumption. However, as a node changes its physical location, spectrum mobility may also follow. Therefore, the treating of node mobility in CRSN imposes new challenges on all network layers, especially in the data link layer. In this paper, we propose a novel cross-layer mobility-aware medium access control (MAC) protocol for CRSN. We also propose an efficient spectrum-aware cluster formation and maintenance. The proposed scheme is more robust against primary users’ activity as well as node mobility in a CRSN because it integrates spectrum sensing at the physical (PHY) layer with packet scheduling at the MAC layer. Simulation results show that the proposed protocol guarantees about 60 % more common channels per cluster in a higher node ratio. Moreover, the proposed MAC protocol outperforms existing protocols (e.g., CogMesh, cluster-based MAC, and KoN-MAC) in terms of the packet delivery ratio, energy consumption, and delay, by up to 5, 30, and 25 %, respectively.

Antipredator Adaptation Shuffled Frog Leap Algorithm to Improve Network Life Time in Wireless Sensor Network

A Wireless Sensor Network (WSN) is an interdisciplinary discipline of sensing, electronics and wireless communication employed widely in environmental monitoring and surveillance applications. The sensor nodes are generally tiny and made of irreplaceable power source and limited capacity for computing, communication, and storage. The power constraint necessitates that the WSN routing protocols conserve energy as critical factor to maximize the network lifetime. Cluster-based approaches are popularly used for its energy efficiency where some nodes designated as Cluster Heads (CHs) organize WSNs for data aggregation and energy saving. The CH is responsible for gathering data from the cluster nodes and conveying it to the base station due to which higher energy drain occurs at CH leading to uneven network degradation. Thus, the selection of CH is critical for improving the WSN performance and lifetime. In this paper, a hybrid Shuffled Frog Leaping Algorithm (AASFLA) with antipredator capabilities to avoid the local minima is proposed. Results show avoidance of suboptimal solution compared to SFLA and particle swarm optimization.

有線給電マルチコプターの自律ホバリング

Though normal multirotor is difficult long flight from restriction of the capacity of power source for using batteries, long operation by wire feeding is useful in limited applications. The control of the multirotor is required enough skill. But the operation has become easier by the aid of attitude and position control using various sensors and GPS in recent years. In this study, hovering control of tethered multicopter is carried out by the detection of tilt angle of tethered cable by using joystick.

Simple Power Flow Control Method for Reducing the Power Source Capacity and Managing the Storage Energy for Hybrid Power Source Electric Vehicles

SUMMARYElectric railway vehicles require high electric power when powering and return high electric output when regenerating. Therefore, the fall in vehicle performance due to a voltage drop and the restriction on regenerative power due to a load shortage become problems in a dc‐electrified railway. Therefore, energy storage devices (ESDs) are mounted on vehicles to assist the power of powering operation and to absorb the power of regeneration. In recent years, various hybrid vehicles have been studied because the performance of ESDs has become good enough for them to be mounted on vehicles. Generally, the design of the controller is a complicated problem because the vehicle operates under various running conditions. In this paper, a simple controller for ESDs is designed in the frequency domain. This controller aims at smoothing the input power and at managing the ESD energy. The proposed controller is examined under various running conditions with numerical simulations.

The evaluation of adaptability among power source, power grid and load based on game theory

As the increase of the capacity of power source, the scale of power grid and load, and the internal and external factors of security and economy on large-scale grid, understanding of the interactions and effects of power source, power grid and load, has very important significance for establishing the evaluation theory system of the adaptability of large-scale power grid. In the aspect of construction and investment, power source, power grid and load belong to different; in the aspect of opration and income, the three must comply with uniform guidelines for the regulation of the power system, and their incomes for each connect by electricity and price. For the problems of investments and incomes of power source, power grid and load, the paper establishs models of substation capacity, generator capacity, load capacity and the relationship of their investment and income based on game theory; the paper also proposes investment and income algorithm of power source, power grid, and load based on the ISO scheduling model. Numerical result demonstrates the effectiveness of game models and the algorithm, at the same time, it also analyses the interaction and influence and finds Nash equilibrium point among power source, power grid and load. These explain behaviors of power source, power grid and load respectively. The evaluation of adaptability among power source, power grid and load is an important part of the evaluation of large scale power grid, the research work and achievements of this paper can analyse the interaction and influence among power source, power grid and load, and calculate the income of each investor under a variety of strategies. And these provide the basis for each investors decision.

A portable air-aluminum power source with an alkaline electrolytic solution

The results from development of a portable air-aluminum chemical power source (AA CPS) with an alkaline electrolytic solution without any additional service circuits are presented. The feasibility of making air cathodes on the basis of a metal-carbon composite produced by the plasma method has been shown. Special features of the operational conditions of a portable AA CPS have been investigated. It has been found that the aluminum cathode passivation when aluminum hydroxide precipitates from a solution significantly restricts the specific capacity of such power sources. It was shown that it is possible to overcome the anode passivation and to considerably increase the specific capacity of an AA CPS with an alkaline electrolytic solution by means of modifying an anode alloy.

A distributed fault localization, isolation and supply restoration algorithm based on local topology

Summary This paper proposes a distributed topology computation for distributed fault localization, isolation and supply restoration (FLISR) algorithm considering switch and communication failures. The algorithm is based on local topology. By message delivered among the adjacent switches, the available capacity and routing information of power source are dynamically updated and stored in each switch. Dyeing method, reselecting a new restoration strategy, blind zone and the timeout design are proposed to solve the interference of switch and communication failures. A distribution network of Tianjin Electric Power Corporation with multiple power source, branches and ties is selected to simulate the FLISR process of the proposed algorithm. The case study shows that the algorithm can be applied to complex distribution network, and has good adaptability. Copyright © 2014 John Wiley & Sons, Ltd.

Simple Power Flow Control Method for Reducing the Power Source Capacity and Managing the Storage Energy for Hybrid Power Source Electric Vehicles

SUMMARY Electric railway vehicles require high electric power when powering and return high electric output when regenerating. Therefore, the fall in vehicle performance due to a voltage drop and the restriction on regenerative power due to a load shortage become problems in a dc-electrified railway. Therefore, energy storage devices (ESDs) are mounted on vehicles to assist the power of powering operation and to absorb the power of regeneration. In recent years, various hybrid vehicles have been studied because the performance of ESDs has become good enough for them to be mounted on vehicles. Generally, the design of the controller is a complicated problem because the vehicle operates under various running conditions. In this paper, a simple controller for ESDs is designed in the frequency domain. This controller aims at smoothing the input power and at managing the ESD energy. The proposed controller is examined under various running conditions with numerical simulations.

전기트랙터의 다양한 작업 환경을 고려한 주행 시뮬레이션에 대한 연구

In this paper, we propose that a model based design for a electric tractor system by using ASM(Automotive Simulation Models). Before developing a realistic electric tractor, it is essential that defining the capacities of power sources and optimizing the parameters of electric tractor. In additionally, because the electric tractor must have not only driving function but also working function, two PMSM are used at electric tractor. ASM which is based on simulink and Carsim were used to design a electric system and powertrain of electric tractor. For verifying the electric tractor system, we compared the design parameters such as max power, state of charge, drive distance, velocity which were carried out by the simulation and experimental method. The predicted results by the development model were in good agreement with the simulation results. According to simulation of tractor, it is possible to arrange the advanced research of dynamical characteristic of tractor and present the guidelines for the electrical driving system.

Power Failure Protection Scheme for Reliable High-Performance Solid State Disks

SUMMARY Solid-state disks (SSDs) have received much attention as replacements for hard disk drives (HDDs). One of their noticeable advantages is their high-speed read/write operation. To achieve good performance, SSDs have an internal memory hierarchy which includes several volatile memories, such as DRAMs and SRAMs. Furthermore, many SSDs adopt aggressive memory management schemes under the assumption of stable power supply. Unfortunately, the data stored in the volatile memories are lost when the power supplied to SSDs is abruptly shut off .S uch power failure is often observed in portable devices. For this reason, it is critical to provide a power failure protection scheme for reliable SSDs. In this work, we propose a power-failure protection scheme for SSDs to increase their reliability. The contribution of our work is three-fold. First, we design a power failure protection circuit which incorporates super-capacitors as well as rechargeable batteries. Second, we provide a method to determine the capacity of backup power sources. Third, we propose a data backup procedure when the power failure occurs. We implemented our method on a real board and applied it to a notebook PC with a contemporary SSD. The board measurement and simulation results prove that our method is robust

Joint Source-Channel Coding and Channelization for Embedded Video Processing With Flash Memory Storage

This paper presents a joint source coding, channel coding, and flash memory channelization design framework to obtain optimized tradeoffs among energy consumption, bit rate, and end-to-end distortion (i.e., optimal E-R-D tradeoff space) for embedded and mobile devices with limited power source and abundant flash memory storage capacity. The optimal E-R-D tradeoff space enables embedded and mobile devices to cohesively optimize the source coding and data storage system operations subject to run-time power source, storage capacity, and/or distortion constraints. By treating flash memory as a communication channel, this work differs from classical joint source-channel coding from two perspectives: i) Classical joint source-channel coding aims to obtain an optimized R-D (bit rate and distortion) tradeoff space, while we aim to obtain an optimized E-R-D tradeoff space; ii) Flash memory can be configured (or channelized) over an energy consumption versus raw bit error rate tradeoff spectrum, and channelization is an integral part of the joint design. With the focus on video coding, this paper presents theoretical investigations and specific approaches for both scenarios where channel can and cannot contribute to end-to-end distortion. Based on detailed power estimation and representative video sequences, we quantitatively demonstrate the application of the proposed design approaches for obtaining optimized E-R-D tradeoff space.

PENETRATION AND INTEGRATION OF WIND POWER PLANTS INTO LITHUANIAN POWER SYSTEM

New Directive of the European Parliament and of the Council on the promotion of the use of energy from renewable sources enables member states of European Union not only to initiate changes in legislation, but also to set the mandatory requirements for renewable energy sources. Therefore the number and capacity of renewable power sources, especially wind power plants, in Lithuania tend to increase very fast. Beside the main advantages of wind power plants, related to environmental and climate changes requirements, some drawbacks, concerning additional balancing and reserve, could be stated. A lot of questions arise, which are related to operation individualities of wind power plants during steady and fault conditions, influence of wind power plants on the operation of transmission network relay protection and automation.

The General Rule of Power Converted from Chemical Energy to Electrical Energy

AbstractElectrochemical power sources are widely used to convert chemical energy to electrical energy. Here we report an equation to describe the electrical power characteristics i.e., potential vs. the current performance curves, namely polarization curves of electrochemical power sources. From this basic equation, we describe the performance curve of general electrochemical power sources with three power source parameters: E0: equilibrium potential; R: internal resistance; and K: power conversion coefficient. The calculated values from this equation agree with the performance curves of power sources such as different type of fuel cells and batteries. The concept of the power convert coefficient is a new criterion to evaluate and compare the characteristics and capacity of different electrochemical power sources.