无线传感器装置网络节能的分析

无线传感器的节点通常依靠电池提供能源,但是电池存储的电能有限,会缩短无线传感器装置网络的使用寿命,因此,如何最大幅度增加传感器装置的寿命是一个重点的研究课题和方向。该文对无线传感器装置的节能效果进行研究,从能耗管理角度借助能量数值估算使得传感器装置的节点在工作时位于中性的能量区间,进而提升其能效。通过实验的结论说明,与常规的方案相比,该方法在能源使用率、吞吐量及功耗层面取得了较大的提升。     

无线传感器网络节点长寿命太阳能供电系统研究

为延长无线传感器网络的使用寿命,研究了如何系统地设计无线传感器网络节点的能量自治系统。提出了基于能量收集技术的太阳能供电系统模型,根据农田信息远程监测系统实施的具体要求,设计了无线传感器网络节点长寿命太阳能供电系统,详细地阐述了系统整体结构、功能模块设计、能量管理策略以及实验器件选型,具体地分析了实验测试性能。实验结果表明,该能量自治系统在实验测试条件下,每天3至4小时的光照时间即可保证无线传感器网络节点以10%的工作占空比持续运行约4至5年。     

嵌入式无线传感器网络研究

简要叙述了无线传感器网络的发展史,讨论了传感器节点的功耗、成本、组网方面的属性及要求,概述了传感器节点的传感单元、通信单元、处理单元及供电单元等四大基本功能单元和两个辅助单元,介绍了一些常用电池和几款适合嵌入式节点设计的微控制器和射频器件,阐述了无线传感器网络领域一些挑战性的问题以及传感器节点的能量管理问题.     

自供电无线振动传感器网络的双模组振动能量收集与管理方法

针对自供电无线振动传感器网络节点在高、低功耗模式下能量供应等待周期长或容量不足的问题,提出一种双模组振动能量收集与管理方法。设计小能量存储容量模组和大能量存储容量模组,小能量存储容量模组蓄能周期短,大能量存储容量模组蓄能容量大。在每个模组中,欠压闭锁电路断开后级电路通路将能量阻断,然后蓄积于电解电容,降压稳压电路降压转换电解电容的高电压能量并存储于超级电容,能源状态监测电路监测超级电容的能源状态,无线振动传感器网络节点微处理器获得能源状态信息后,根据后续工作的能量供应需求启用不同的蓄能模组。实验结果表明:双模组振动能量收集与管理电路最短蓄能周期仅6 min,完全启动双模组的情况下每个蓄能周期提供高达4.19 J的能量,能够驱动无线振动传感器网络节点正常工作。     

无线传感器网络WSN硬件设计

传感器网络节点作为一种微型化的嵌入式系统,构成了无线传感器网络的基础层支撑平台。因为无线传感器网络大部分是采用电池供电,工作环境通常比较恶劣,而且数量大,更换电池非常困难,所以低功耗是无线传感器网络最重要的设计准则之一,从无线传感器网络节点的硬件设计到整个网络各层的协议设计都把节能作为设计的目标之一,尽可能延无线传感器网络的寿命。本文介绍了无线传感器网络的概念、特点以及无线传感器网络节点的组成,重点分析比较节点各组成单元各种常用芯片的特点,并且始终将低功耗作为比较的重要标准之一。     

应用于无线传感器节点的微小型复合能源收集系统(英文)

设计并实现了一种可应用于无线传感器节点的复合能源系统样机,基于一种无线地磁交通流传感器,提出了本文的设计目标.选择太阳能、风能、应变能作为系统的能量源.根据这3种不同能量源的特性,对能量管理模块与能量储存模块进行了针对性设计,最后实现并测试了样机.实验结果表明,该样机可连续35 h在3.55 V电压下输出50mW的电能.     

无电池振动传感器节点的研究

随着集成电路和微机电系统技术的发展,小尺寸、低成本、低能耗的电路与传感器的研发取得了巨大的进展,使大型无线传感器网络的构建成为可能。无线传感器网络节点一般处在野外恶劣的环境中,不允许更换电池,但是为节点提供能量的化学电池往往具有尺寸大、寿命有限等缺点,使得无线传感器网络在具体应用中受到了限制,自供电成为无线传感器网络研究的一个重要课题。     

振动式微型发电机的研究进展

振动能量采集系统可广泛应用于为无线传感器节点和低功耗电子设备供电。振动式微型发电机是振动能量采集系统中的关键部件，可分为电磁式、压电式、静电式、磁致伸缩式和复合式等类型。本文综述了振动式微型发电机结构、形式、以及理论仿真模型的最新进展，分析了振动式微型发电机面临的困难和发展趋势。     

微型大气电场监测装置的设计与实现

针对户外场磨式地面电场仪存在的输入阻抗高、感应电流信号弱、易受外界电磁波干扰、功耗大且无市电供电等问题,设计一种光伏发电加蓄电池储能供电的低功耗大气电场监测装置。为减小系统功耗,提高测量精度,设计微型低速双定子差分式电场传感器,传感器感应到的两路微弱电流信号经过T型反馈网络实现I/U变换。通过减法器和4 Hz低通滤波器消除共模干扰和工频干扰,提高信号的信噪比。利用光传感器采集同步感应信号,与AD630锁相放大器配合对信号进行处理,得到与场强成正比例关系的直流电压。经实验验证,系统在–50~50 kV/m的模拟电场强度范围内,测量分辨力可达到10 V/m,测量线性度<1%。所设计系统能够在光伏供电的情况下独立运行,实时测量大气电场强度并将测量结果传输到上位机,为雷电监测预警提供必要的数据支持。     

新型光伏储电原位集成电池研究进展

随着光伏智能电子产品日益融入到日常生活, 人们不仅对高性能光伏发电设备的需求增加, 同时对智能化、可持续和快速充电/放电能源集成设备的需求也急剧增加, 将能量产生部件和能量存储部件结合成独立设备已经成为一种极具有吸引力和挑战性的前沿技术。原位逐层制备光电转换功能薄膜与储电功能薄膜并组装, 获得光伏储电原位集成电池的技术, 既减少了太阳光波动对能量输出的影响, 又可以实现光伏自供电、弱光缓冲和可穿戴等功能, 因此具有良好的发展前景。本文综述了硅基光伏储电原位集成电池、敏化光伏储电原位集成电池、钙钛矿光伏储电原位集成电池的最新研究成果, 介绍了此类新型电池性能的评价方法, 分析了其工作原理、构造特点和性能参数, 并对此新兴研究领域的发展趋势进行了展望。     

Photovoltaics in the assessment of wireless sensor network reliability with changing environmental conditions

This paper presents a reliability assessment of a wireless sensor network (WSN) equipped with mini photovoltaic cells (PV‐WSN) under natural environmental conditions while accounting for different types of system failures. In particular, our assessment considers the hardware specifications of the sensors, photovoltaic (PV) specifications, the use of rechargeable batteries, communication protocols, and various elements required for efficient detection of environmental conditions. We accomplished this by developing a simulator that generated data for 2 broad WSN conditions: (1) WSN without PV and (2) WSN with PV. The dynamic source routing protocol was employed for these simulations, and the following variables were assessed for both conditions: WSN reliability, the impact of energy consumption on the network, and the types of failures that lead to sensor unavailability. The following assumptions were made to run the simulation: the distribution of WSN nodes is random, with 1 sink node per rectangular cluster, the sensor nodes are structurally and functionally identical, environmental interference and suboptimal orientation impair PV cell recharge capacity randomly, and no communication loss occurs. Our reliability assessment assumed extreme environmental conditions and further made assessments of component reliability that included the following parameters: sensor and PV cell hardware specifications, the rechargeable nature of PV cell batteries for different sensor activity states, the availability of sunlight for powering PV cells, and the energy efficiency of PV cells. We found that network lifetime was prolonged for the PV‐WSN condition over the WSN without PV condition, introducing a role for PV cells as potential energy sources for WSNs.     

Hybrid Micropower Source for Wireless Sensor Network

Wireless sensor networks have become a very significant enabling technology in many applications and the use of environmental energy is a feasible source for low-power wireless sensor networks. The challenges of developing a power supply including generation or conversion, storage, and power management are manifold to extend the lifetime of a wireless sensor network. The objective of this research is to develop an intelligent hybrid power system to realize a self-sustaining wireless sensor node. The photovoltaic and thermoelectric generators are adopted as energy converters. The lithium ion battery and ultracapacitor are used as reservoirs. An intelligent power management system has been developed to control the power distribution. The design data and experimental results show that the hybrid micropower source can extend the lifetime of a sensor network.     

Dust sensor based on luminescent glazing for control of photovoltaic panels cleaning

The installation of photovoltaic panels in dusty areas affects their efficiency by the accumulation of dust on glazing surfaces. The cleaning of the dusty panels allows recovering the maximum efficiency. However, it increases the cost of operating and maintenance for photovoltaic installations, a compromise between the reduction in the annual cleaning cost and the improvement solar energy production is obtained with implementation of a dust sensor. By this study, for a first time a dust sensor is developed by using luminescent glazing material with embedded photocells on borders. The dust deposited on sensor is detected from photogenerated current from the photocell integrated on the edges of a luminescent glass plate of 10 × 10 cm² area. The optical and electrical characterization revealed that the generated photocurrent from the sensor output increases of 9 µA when dusts accumulation shading is widen by 10%. This new principal for dust sensors could be applied to monitor photovoltaic power plant installations for maximizing energy production from solar renewable source in dusty environment as like Saharan regions. In order to start the cleaning cycle of the photovoltaic modules, the signal generated by the dust sensor is amplified by a Darlington analog circuit which assures the relay control for operating of a direct current pump.     

Controlled deployments for wireless sensor networks

In wireless sensor networks (WSNs), the operation of sensor nodes has to rely on a limited supply of energy (such as batteries). To support long lifetime operation of WSNs, an energy-efficient way of sensor deployment and operation of the WSNs is necessary. A new controlled layer deployment (CLD) protocol to guarantee coverage and energy efficiency for a sensor network is proposed. CLD outperforms previous similar protocols in that it can achieve the same performances and guarantee full area coverage and connection using a smaller number of sensors. It can also ameliorate the 'cascading problem' that reduces the whole network lifetime. Finally, analysis and simulation results show that CLD can use fewer sensor nodes for coverage and also increases the lifetime of the sensor network when compared with the probing environment and adapting sleeping (PEAS) protocol.     

Hybrid Energy Harvesters: Toward Sustainable Energy Harvesting

Recently, sustainable green energy harvesting systems have been receiving great attention for their potential use in self‐powered smart wireless sensor network (WSN) systems. In particular, though the developed WSN systems are able to advance public good, very high and long‐term budgets will be required in order to use them to supply electrical energy through temporary batteries or connecting power cables. This report summarizes recent significant progress in the development of hybrid nanogenerators for a sustainable energy harvesting system that use natural and artificial energies such as solar, wind, wave, heat, machine vibration, and automobile noise. It starts with a brief introduction of energy harvesting systems, and then summarizes the different hybrid energy harvesting systems: integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. In terms of the reported hybrid nanogenerators, a systematic summary of their structures, working mechanisms, and output performances is provided. Specifically, electromagnetic induction, triboelectric, piezoelectric, photovoltaic, thermoelectric, and pyroelectric effects are reviewed on the basis of the individual and hybrid power performances of hybrid nanogenerators and their practical applications with various device designs. Finally, the perspectives on and challenges in developing high performance and sustainable hybrid nanogenerator systems are presented.     

ECO-BAT: A New Routing Protocol for Energy Consumption Optimization Based on BAT Algorithm in WSN

Wireless sensor network (WSN) has been widely used due to its vast range of applications. The energy problem is one of the important problems influencing the complete application. Sensor nodes use very small batteries as a power source and replacing them is not an easy task. With this restriction, the sensor nodes must conserve their energy and extend the network lifetime as long as possible. Also, these limits motivate much of the research to suggest solutions in all layers of the protocol stack to save energy. So, energy management efficiency becomes a key requirement in WSN design. The efficiency of these networks is highly dependent on routing protocols directly affecting the network lifetime. Clustering is one of the most popular techniques preferred in routing operations. In this work we propose a novel energy-efficient protocol for WSN based on a bat algorithm called ECO-BAT (Energy Consumption Optimization with BAT algorithm for WSN) to prolong the network lifetime. We use an objective function that generates an optimal number of sensor clusters with cluster heads (CH) to minimize energy consumption. The performance of the proposed approach is compared with Low-Energy Adaptive Clustering Hierarchy (LEACH) and Energy Efficient cluster formation in wireless sensor networks based on the Multi-Objective Bat algorithm (EEMOB) protocols. The results obtained are interesting in terms of energy-saving and prolongation of the network lifetime.     

微传感器最新发展

近年来，微传感器受到国际传感技术界的广泛关注，本文介绍十多个微传感器，包括三轴加速度计，单，双轴加速度计片，表面微机械陀螺（角速度传感器），微惯性导航系统，微磁通门传感器，磁阻传感器，纳米皮拉尼压力传感器，微科氏质量流量计，毫米波图像传感器，GPS手表（1cm^3)，二氧化碳传感器和微/超微角位移传感器，文事简要介绍它们的基本结构。敏感机理，特点等，从中可以看出微传感器已成为传感技术中有重要应用前景的组成部分。     

Local mapping of generation and recombination lifetime in BiFeO3 single crystals by scanning probe photoinduced transient spectroscopy

Carrier lifetime in photoelectric processes is the average time an excited carrier is free before recombining or trapping. Lifetime is directly related to defects and it is a key parameter in analyzing photovoltaic effects in semiconductors. We show here a scanning probe method combined with photoinduced current spectroscopy that allows mapping with nanoscale resolution of the generation and recombination lifetimes. Using this method we have analyzed the mechanism of the abnormal photovoltaic effect in multiferroic bismuth ferrite, BiFeO(3). We found that generation and recombination lifetimes in BiFeO(3) are large due to complex generation and recombination processes that involve shallow energy levels in the band gap. The domain walls do not play a major role in the photovoltaic mechanism.     

基于能耗均衡的水下传感器网络分簇路由算法

针对水下传感器网络能耗不均衡问题,提出一种能耗均衡的多跳非均匀分簇路由算法。算法在水下传感器网络非均匀分簇的基础上,通过改进节点簇头竞选的阈值计算方式,解决了网络后期簇头竞选阈值低导致的网络能耗激增;通过引入多跳路由选择公式,综合考虑节点剩余能量和链路能耗,延长网络生命周期。仿真表明,提出的算法生成簇头数目稳定,能耗较低,并且能有效延长水下传感器网络的生命周期。     

国内外用户侧光储系统发展应用研究

随着分布式光伏越来越多地接入电网,光储系统作为提高系统稳定性、减少用户用电成本的有效手段,已成为新能源应用的重要发展方向。首先研究了欧美、日本等发达国家用户侧光储系统应用现状,并在此基础上总结了国外用户侧光储系统发展的重要条件和技术路线。然后,介绍了国内商业用户、工业用户和居民用户光储项目,分析了国内用户侧光储系统发展所面临的难题和困境。最后,根据国外应用经验,结合国内电动汽车充电桩迅速发展的现状,提出了发展建议,对国内用户侧光储项目的健康发展具有一定的借鉴意义。