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排序方式: 共有1909条查询结果,搜索用时 31 毫秒
1.
Lingguo Kong Liangyuan Li Guowei Cai Chuang Liu Ping Ma Yudong Bian Tao Ma 《International Journal of Hydrogen Energy》2021,46(3):2847-2861
With the increasing proportion of renewable energy (mainly wind power and photovoltaic) connected to the grid, the fluctuation of renewable energy power brings great challenges to the safe and reliable operation of power grid. As a clean, low-carbon secondary energy, hydrogen energy is applied in renewable energy (mainly wind power and photovoltaic) grid-connected power smoothing, which opens up a new way of coupling hydrogen storage energy with renewable energy. This paper focuses on the optimization of capacity of electrolyzers and fuel cells and the analysis of system economy in the process of power output smoothing of wind/photovoltaic coupled hydrogen energy grid-connected system. Based on the complementary characteristics of particle swarm optimization (PSO) and chemical reaction optimization algorithm (CROA), a particle swarm optimization-chemical reaction optimization algorithm (PSO-CROA) are proposed. Aiming at maximizing system profit, the capacity of electrolyzers and fuel cells are constrained by wind power fluctuation, and considering environmental benefits, government subsidies and time value of funds, the objective function and its constraints are established. According to the simulation analysis, by comparing the calculated results with PSO and CROA, it shows that PSO-CROA effectively evaluates the economy of the system, and optimizes the optimal capacity of the electrolyzers and fuel cells. The conclusion of this paper is of great significance for the application of hydrogen energy storage in the evaluation of power smoothness and economy of renewable energy grid connection and the calculation of economic allocation of hydrogen energy storage capacity. 相似文献
2.
为了解决互质阵列下DOA(Direction of Arrival)估计算法因使用空间平滑预处理而带来的阵列有效孔径损失、分辨率降低等问题,提出了一种矩阵重叠预处理方法.该方法通过分割空间平滑协方差矩阵,利用其子矩阵具有相同信号子空间的特性,将子矩阵进行重叠处理,扩展协方差矩阵行数,进而增大有效孔径.仿真实验结果表明:所提方法可以提高DOA估计的分辨率,低快拍下的估计精确度也有所提高.同时,本文将U-ESPRIT(Unitary Estimation of Signal Parameter via Rotational Invariance Techniques)算法应用在互质阵列上,通过使用矩阵重叠预处理并结合U-ESPRIT算法,取得了较传统方法更为准确的DOA估计效果. 相似文献
3.
Guiyong Zhang Zecong Chen Zhixiang Sui Dongsong Tao Zhicheng He Qian Tang Lei Sun 《International journal for numerical methods in engineering》2019,119(6):548-566
It is well known that the finite element method (FEM) encounters dispersion errors in coping with mid-frequency acoustic problems due to its “overly stiff” nature. By introducing the generalized gradient smoothing technique and the idea of condensed shape functions with virtual nodes, a cell-based smoothed radial point interpolation method is proposed to solve the Helmholtz equation for the purpose of reducing dispersion errors. With the properly selected virtual nodes, the proposed method can provide a close-to-exact stiffness of continuum, leading to a conspicuous decrease in dispersion errors and a significant improvement in accuracy. Numerical examples are examined using the present method by comparing with both the traditional FEM using four-node tetrahedral elements (FEM-T4) and the FEM model using eight-node hexahedral elements with modified integration rules (MIR-H8). The present cell-based smoothed radial point interpolation method has been demonstrated to possess a number of superiorities, including the automatically generated tetrahedral background mesh, high computational efficiency, and insensitivity to mesh distortion, which make the method a good potential for practical analysis of acoustic problems. 相似文献
4.
The container cloud represented by Docker and Kubernetes has the advantages of less additional resource overhead and shorter start-up and destruction time.However there are still resource management issues such as over-supply and under-supply.In order to allow the Kubernetes cluster to respond “in advance” to the resource usage of the applications deployed on it,and then to schedule and allocate resources in a timely,accurate and dynamic manner based on the predicted value,a cloud resource prediction model based on triple exponential smoothing method and temporal convolutional network was proposed,based on historical data to predict future demand for resources.To find the optimal combination of parameters,the parameters were optimized using TPOT thought.Experiments on the CPU and memory of the Google dataset show that the model has better prediction performance than other models. 相似文献
5.
随着分布式电源的接入, 配电网故障过电流方向不再唯一, 传统的故障区段定位方法将不适用, 本文提出含分布式电源(Distributed Generation,DG)配电网故障区段定位的非线性互补约束光滑化模型和求解方法。基于逻辑关系的间接故障定位方法在数值稳定性和决策效率上的不足, 本文构建了可适应多个DG投切情况的基于代数关系的开关函数。2个仿真算例与对比实验表明, 含DG配电网故障区段定位的非线性互补约束光滑化方法在进行故障定位时具有较高的容错性能, 且能够实现多信息畸变下的准确定位, 由此可见本方案在数值稳定性上胜于智能算法。 相似文献
6.
基于斜平面平滑的半全局匹配算法虽然能很好地处理深度不连续区域,减少视差断裂现象,具有很好的视差平滑效果.但此方法计算量大,并且若输入的左右图像对不是理想校正的,最终得到的视差图中可能会出现黑色小方块.针对上述问题,本文提出了一种基于斜平面平滑优化的双目立体视觉算法,优化了视差斜平面拟合过程,提高了斜平面平滑的运算速度;另,通过对初始视差图中无效的视差值进行临近插值填充,很好地解决了视差图中的方块现象;同时考虑到同一分割块内的像素梯度值应比较接近,对图像分割时用到的能量函数增加梯度项,使分割区域更加合理.实验结果表明,本文算法能取得更好的视差图,主观效果得到改善,运算速度提高约40%. 相似文献
7.
This article introduces a new class of functional-coefficient predictive regression models, where the regressors consist of auto-regressors and latent factor regressors, and the coefficients vary with certain index variable. The unobservable factor regressors are estimated through imposing an approximate factor model on high dimensional exogenous variables and subsequently implementing the classical principal component analysis. With the estimated factor regressors, a local linear smoothing method is used to estimate the coefficient functions (with appropriate rotation) and obtain a one-step ahead nonlinear forecast of the response variable, and then a wild bootstrap procedure is introduced to construct the prediction interval. Under regularity conditions, the asymptotic properties of the proposed methods are derived, showing that the local linear estimator and the nonlinear forecast using the estimated factor regressors are asymptotically equivalent to those using the true latent factor regressors. The developed model and methodology are further generalized to the factor-augmented vector predictive regression with functional coefficients. Finally, some extensive simulation studies and an empirical application to forecast the UK inflation are given to examine the finite-sample performance of the proposed model and methodology. 相似文献
8.
In this work, we present a simultaneous untangling and smoothing technique for quadrilateral and hexahedral meshes. The algorithm iteratively improves a quadrilateral or hexahedral mesh by minimizing an objective function defined in terms of a regularized algebraic distortion measure of the elements. We propose several techniques to improve the robustness and the computational efficiency of the optimization algorithm. In addition, we have adopted an object-oriented paradigm to create a common framework to smooth meshes composed by any type of elements, and using different minimization techniques. Finally, we present several examples to show that the proposed technique obtains valid meshes composed by high-quality quadrilaterals and hexahedra, even when the initial meshes contain a large number of tangled elements. 相似文献
9.
10.
本文给出了一种求解对称锥互补问题的非精确光滑牛顿方法,所采用的互补函数是含一个参数且以FB和CHKS为特例的光滑函数.新方法的每步迭代中,都采用非精确牛顿方法求解由原问题产生的子问题.在一定条件下,新算法具有全局收敛和局部超线性收敛的性质.数值试验表明算法对于求解大规模对称锥互补问题是非常有效的. 相似文献