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101.
Wireless Power Transmission is an emerging technology that enables the transmission of electricity without the use of artificial conducting mediums. Lack of significant technological breakthroughs widely affected its progress. In this paper, we analyze the early progress of WPT and attempt to forecast its growth using Pearl curve model. Fisher-Pry substitution model analysis indicates that technology substitution of wired transmission has just begun and half the substitution will be over by 2028. We conducted patent landscaping to identify hot domains and specific technology areas. Implications for technology developers and manufacturers, electric utility providers and national policymakers are also identified. 相似文献
102.
An Improved Torque Sensorless Speed Control Method for Electric Assisted Bicycle With Consideration of Coordinate Conversion 下载免费PDF全文
Tinghua Li Qinghua Yang Xiaowei Tu Bin Ren 《IEEE/CAA Journal of Automatica Sinica》2020,7(6):1575-1584
In this paper, we propose an improved torque sensorless speed control method for electric assisted bicycle, this method considers the coordinate conversion. A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling. A DC motor provides assisted power driving, the assistance method is based on the real-time wheel angular velocity and coordinate system transformation. The effect of observer is proved, and the proposed method guarantees stability under disturbances. It is also compared to the existing methods and their performances are illustrated through simulations. The proposed method improves the performance both in rapidity and stability. 相似文献
103.
针对大型风力发电机机组中常见的脉动湍流、风机尾流与涡流等湍流信号,研究了利用自然梯度下降的独立分量分析方法的湍流频谱分离效果,以区分中心风速与湍流信号,提高风机机组的综合工作效率。首先分析了风机组中常见湍流信号的后向散射与频谱分布特点,然后依据这些特点设计了对应的独立分量分析模型。在仿真结果符合要求的基础上,进行了双目激光雷达天线的风速采集与实际分离效果检测。实验结果表明,在大气折射率结构常数C2n≤10-14同时广义大气常数α≥4的通常情况下,利用双目信号能够分离出一个湍流中心和一个中心风速。对1 s内两个谱峰的波动范围进行统计,获得(2.59±0.05)MHz的中心风速以及(1.22±0.19)MHz的湍流中心估计,且二者的平均信噪比分别为25.93 dB和31.01 dB,能够在获得稳定的中心风速估计的同时得到一个较为稳定的湍流中心估计。 相似文献
104.
Wind power and photovoltaic power: How to improve the accommodation capability of renewable electricity generation in China? 下载免费PDF全文
China's wind curtailment and photovoltaic curtailment was one of the prominent issues in 2014, and the renewable curtailment worsened in 2015. With the rapid growth of renewables, the phenomenon of the insufficiency in renewable accommodation capability is becoming more and more serious in 2016. In that case, the problem of the insufficient accommodation capability is pointed out by analyzing China's development requirements. The renewable power generation scale, the renewable power consumption, and the restrictions on the renewable electricity generation are discussed from the China's market perspective. Meanwhile, the legal environment, the planning requirement, the institutional setting, and the policy tools are introduced from the perspective of governmental regulation. An empirical analysis, a cause analysis and a trend analysis are illustrated before explaining the problem of renewable curtailment and proposing a solution for enhancing the accommodation capability. According to the analysis results, the solution for addressing the wind curtailment and PV curtailment is offered with respect to the technology, the institution, the legislation, and the political aspect. Through the research, the research conclusions are drew finally and the corresponding policy recommendations are put forward. 相似文献
105.
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107.
Benedetto Rocchio Claudio Chicchiero Maria Vittoria Salvetti Stefania Zanforlin 《风能》2020,23(4):915-938
The present study is focused on modeling of dynamic stall behavior of a pitching airfoil. The deep stall regime is in particular considered. A model is proposed, which has a low implementation and computational complexity but yet is able to deal with different types of dynamic stall conditions, including those characterized by multiple vortex shedding at the airfoil leading edge. The proposed model is appraised against an extensive data set of experimental (α,CL) curves for NACA0012. The results of an existing widely used model, having comparable complexity, are also shown for comparison. The proposed model is able to well reproduce not only the classic curves of deep dynamic stall but also the curves characterized by lift oscillations at high angles of attack due to the shedding of multiple vortices. Furthermore, the model appears to be robust to variations of its parameters from the optimal values and of the airfoil geometry. Finally, the model is successfully implemented in a commercial CFD software and applied to the simulation of a vertical axis wind turbine within the actuator cylinder approach. The accuracy of the prediction of the turbine power coefficient in the whole rotation cycle is very good for the optimal working condition of the turbine, for which the model parameters were calibrated. Fairly good accuracy is also obtained in significantly different working conditions without any further calibration. 相似文献
108.
泛在电力物联网是物联网在电力领域的具体体现,建设泛在电力物联网是推进"三型两网"建设的关键环节,也是实现能源转型的必要手段。阐述了泛在电力物联网的定义,从供电公司角度出发,根据北京经济技术开发区实际情况,讨论了依托地区特点的泛在电力物联网实施策略和实际应用场景,分析了可能遇到的问题。得出结论:随着泛在电力物联网的深入建设,供电公司能够为电力客户提供多元化服务,提高客户满意度;地市供电公司能够依托泛在电力物联网开展更多电力相关业务;泛在电力物联网的安全性、实用性、有效性是发展面临的首要问题。 相似文献
109.
电力系统维护是电力系统稳定运行的重要保障,应用智能算法的无人机电力巡检则为电力系统维护提供便捷。电力线提取是自主电力巡检以及保障飞行器低空飞行安全的关键技术,结合深度学习理论进行电力线提取是电力巡检的重要突破点。本文将深度学习方法用于电力线提取任务,结合电力线图像特点嵌入改进的图像输入策略和注意力模块,提出一种基于阶段注意力机制的电力线提取模型(SA-Unet)。本文提出的SA-Unet模型编码阶段采用阶段输入融合策略(Stage input fusion strategy, SIFS),充分利用图像的多尺度信息减少空间位置信息丢失。解码阶段通过嵌入阶段注意力模块(Stage attention module,SAM)聚焦电力线特征,从大量信息中快速筛选出高价值信息。实验结果表明,该方法在复杂背景的多场景中具有良好的性能。 相似文献
110.
Energy management of hybrid photovoltaic (PV)-battery systems still serve as a challenging task owing to their complex and nonlinear characteristics, multicomponent structures, and the extensive range of environmental factors disturbing their nominal performance. The hybrid energy system developed in this study encompasses PV arrays, a battery component, one boost converter, and one bidirectional boost converter. In this paper, we propose a novel adaptive robust control framework for the optimal energy management of the PV-battery systems under many operating conditions and subject to unmodelled dynamics. An improved exponential-like adaptive integral sliding mode (EISM) control coupled to neural network approximator is introduced using a multi-rate convergence tweaking mechanism for the sliding surface to improve the transient performance of the closed-loop system. Furthermore, the entire dynamics of the hybrid energy system is considered unknown, unlike the previous studies that only assumed the parametric uncertainties. The global asymptotic stability of the system is guaranteed, and the effectiveness of this novel framework is compared to benchmark studies. 相似文献