直激式压电风力发电机的结构及其特性

随着无线传感网络技术的日趋成熟及其在环境监测等领域应用的普及,为其供电的微小型流体发电机研究受到国内外学者的广泛关注,其中利用压电进行风能回收已成为一个研究热点。首先,介绍了现有压电风力发电机的优势、特点及适用场合;其次,重点对直激式压电风力发电技术的发展概况与研究进展进行了分析与总结,归纳了直激式压电风力发电机的主要结构、基本原理、特性及应用情况;最后指出目前直激式压电风力发电机以梁式结构为主,振动方式以颤振和弛振为主,且缺乏统一的数学模型,以及现有的发电机存在结构可靠性低、稳定性较差等问题。以宽频带、高可靠性和集群布置为进一步发展趋势,以期推动直激式压电风力发电机的进一步发展与应用。     

基于风致振动机理的微型压电风能采集器

提出一种基于风致振动机理的微型风能采集装置,可将风能转换为电能加以利用。装置主要包括腔体和压电薄膜振动传感器,传感器一端固定,另一自由端附加细长圆柱体结构。利用细长圆柱体在气流中更易诱发涡激振动的原理,并结合结构体在一定气流条件下存在的其他风致振动机理,该装置可将风能转换为压电薄膜传感器的振动,然后进一步转换为电能。本结构设计尺寸为30mm×16mm×14mm,在风速为7m/s,外加负载为1.8 MΩ时,可以获得0.84μW的有效功率。同时可通过并列增加压电薄膜梁结构的数量来提高能量采集的效率。     

风能、太阳能电网设计

21世纪,能源领域将重点放在核能、风能及太阳能等领域,各个国家也都相继提出自己的优惠政策,因此设计出切实可行的新能源运行方案是非常之必要的。基于此,阐述了风能、太阳能发电、储能、并网的关联可行方案,全部采用环保无污染产品作为基础搭建。     

悬臂梁基底对压电俘能器输出响应的影响分析

悬臂梁的材料与结构对压电俘能器的输出响应具有重要影响。为了研究在1.5～5.8 m/s低风速环境下不同基底材料对接触式压电俘能器的影响,该文选择聚氯乙烯(PVC)、304不锈钢、1060铝和H68黄铜材料为基底的柔性聚偏氟乙烯(PVDF)压电悬臂梁结构,并进行了对比实验与分析。结果表明,以304不锈钢为基底的悬臂梁结构输出功率最大。通过计算不同基底材料梁的结构参数发现,在低风速工况下,梁的结构刚度与减幅因数是影响压电俘能器输出性能的主要因素。同等工况下,梁的结构刚度越小,接触式压电俘能器的启动风速越低,风致振动的激振力频率越高;减幅因数越小,悬臂梁的输出功率越大。     

变速恒频双馈风力发电系统最优风能捕获控制

从分析风力机运行特性出发，研究实现最优风能捕获的系统控制方法。并采用定子磁场定向的矢量控制技术，对双馈发电机转子进行交流励磁，实现发电机有功、无功及转速的独立控制，从而获得最大风能捕获的高效发电运行。仿真结果验证了文中所提出控制策略的正确性和有效性。     

基于行车风压的谐振腔式压电俘能器研究

针对汽车行驶过程中车载传感器需要持续稳定的供能需求,设计一种以谐振腔结构为主体,扰流圆柱与亥姆霍兹谐振腔为辅助的压电俘能器。为研究俘能器的发电性能,设计其最佳结构,建立流固电耦合仿真模型。仿真时,根据实际风压分布,将风压载荷分区加载到压电发电模块。仿真分析结果表明,基板与压电陶瓷的厚度比对压电悬臂梁的输出电压和固有频率有影响,最佳厚度比为1.25;基板与主腔体间间隙、扰流圆柱直径、亥姆霍兹谐振腔皆存在最佳尺寸参数使压电俘能器发电性能达到最佳;负载电阻在400～600 kΩ内时,可获得最佳的输出功率;风速为15 m/s时,最大输出功率为37.3 mW。     

风能与动力工程专业的课程体系探讨

本文立足于我国风能产业的发展现状和趋势,对风能专业人才需求结构和教育衔接进行了细致分析研究,在综合分析目前国内9所设置本专业高校所制定的课程体系的基础上,我们提出了一种可行的风能与动力工程专业课程体系方案,可对专业建设起到教好的促进作用。     

Battery Energy Storage to Strengthen the Wind Generator in Integrated Power System

The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem.This weak interconnection of wind generating source in the electrical network affects the power quality and reliability.The localized energy storages shall compensate the fluctuating power and support to strengthen the wind generator in the power system,in this paper,it is proposed to control the voltage source inverter(VSI)in current control mode with energy storage,that is,batteries across the dc bus.The generated wind power can be extracted under varying wind speed and stored in the batteries.This energy storage maintains the stiff voltage across the dc bus of the voltage source inverter.The proposed scheme enhances the stability and reliability of the power system and maintains unity power factor,it can also be operated in stand-alone mode in the power system.The power exchange across the wind generation and the load under dynamic situation is feasible while maintaining the power quality norms at the common point of coupling.It strengthens the weak grid in the power system.This control strategy is evaluated on the test system under dynamic condition by using simulation.The results are verified by comparing the performance of controllers.     

基于风力发电系统的电能变换装置研究

针对目前独立运行风力发电系统通过＂交流-直流-交流＂的转换方式供电时,存在能量利用率偏低,且往往达不到负载需求电能的缺点,采用了DC/DC升压及DC/AC逆变技术在风力发电能量转换体系中,设计了一种新型的能量供应体系及其控制策略,并在此基础上应用Matlab/Simulink搭建了仿真程序。通过仿真,得到了用户需要的稳定交流电能,验证了控制策略的正确性及控制方案的可行性,具有很好的推广应用价值和进一步的研究价值。     

Achieving High-Efficiency Wind Energy Harvesting Triboelectric Nanogenerator by Coupling Soft Contact,Charge Space Accumulation,and Charge Dissipation Design

To enhance the durability of a triboelectric nanogenerator (TENG), soft contact is an effective approach due to its flexible and elastic contact mode. However, soft contact is hard to obtain with a large charge density by triboelectrification, resulting in low power output. Herein, a novel blade soft contact TENG (BSC-TENG), coupling flexible functional blades with shielded electrodes on the rotor, charge accumulation, and charge dissipation design on the stator, is proposed. Extra polishing blades and debris storage grooves are adopted in the BSC-TENG to further ensure high durability. A remarkable charge density of 328 µC m⁻² is achieved, setting a new record for soft contact TENGs. Besides, the output charge remains at 100% even after 200 000 cycles. The wind-driven BSC-TENG not only can power 3840 green LEDs and 80 parallel hygrothermometers but also can drive electronic devices for smart farms, establishing self-powered sensing systems. This work provides a novel strategy for enhancing soft contact TENG output and durability.     

Super‐Flexible Nanogenerator for Energy Harvesting from Gentle Wind and as an Active Deformation Sensor

Using an Al‐foil of thickness ≈18 μm as a substrate and electrode, a piezoelectric nanogenerator (NG) that is super‐flexible in responding to the wavy motion of a very light wind is fabricated using ZnO nanowire arrays. The NG is used to harvest the energy from a waving flag, demonstrating its high flexibility and excellent conformability to be integrated into fabric. The NG is applied to detect the wrinkling of a human face, showing its capability to serve as an active deformation sensor that needs no extra power supply. This strategy may provide a highly promising platform as energy harvesting devices and self‐powered sensors for practical use wherever movement is available.     

Prolifera‐Green‐Tide as Sustainable Source for Carbonaceous Aerogels with Hierarchical Pore to Achieve Multiple Energy Storage

The increasing demand for efficient energy storage and conversion devices has aroused great interest in designing advanced materials with high specific surface areas, multiple holes, and good conductivity. Here, we report a new method for fabricating a hierarchical porous carbonaceous aerogel (HPCA) from renewable seaweed aerogel. The HPCA possesses high specific surface area of 2200 m² g^?1 and multilevel micro/meso/macropore structures. These important features make HPCA exhibit a reversible lithium storage capacity of 827.1 mAh g^?1 at the current density of 0.1 A g^?1, which is the highest capacity for all the previously reported nonheteroatom‐doped carbon nanomaterials. It also shows high specific capacitance and excellent rate performance for electric double layer capacitors (260.6 F g^?1 at 1 A g^?1 and 190.0 F g^?1 at 50 A g^?1), and long cycle life with 91.7% capacitance retention after 10 000 cycles at 10 A g^?1. The HPCA also can be used as support to assemble Co₃O₄ nanowires (Co₃O₄@HPCA) for constructing a high performance pseudocapacitor with the maximum specific capacitance of 1167.6 F g^?1 at the current density of 1 A g^?1. The present work highlights the first example in using prolifera‐green‐tide as a sustainable source for developing advanced carbon porous aerogels to achieve multiple energy storage.