scholarly journals Spectral correction method based on improved flat-top convoluted window for parameter estimation of power harmonic

2017 ◽  
Vol 24 (1) ◽  
2009 ◽  
Vol 26 (3) ◽  
pp. 647-655 ◽  
Author(s):  
Satoshi Sakai ◽  
Aya Ito ◽  
Kazuhiro Umetani ◽  
Isao Iizawa ◽  
Masanori Onishi

Abstract A simple directional pyrgeometer is tested and compared with a conventional standard pyrgeometer. The system presented in this article has a narrow directional response and points to the representative zenith angle of 52.5°. Because of its directional response, it can be used in a street canyon or in a forest provided that a small part of the sky is visible at the representative angle. The system can be assembled using inexpensive parts that are widely used in household appliances. As this system does not have a flat spectral sensitivity, a spectral correction method is also presented. The results show that the output of the new system agrees well with that from a conventional pyrgeometer (Kipp & Zonen CG3). The correlation coefficient is 0.995 and the standard deviation is 5.6 W m−2 for 1-h averaged values.


2021 ◽  
Vol 12 (1) ◽  
pp. 66
Author(s):  
Wenwu Yi ◽  
Ziqi Lu ◽  
Junbo Hao ◽  
Xinge Zhang ◽  
Yan Chen ◽  
...  

Based on the classical spectral representation method of simulating turbulent wind speed fluctuation, a harmonic superposition algorithm was introduced in detail to calculate the homogeneous turbulence wind field simulation in space. From the view of the validity of the numerical simulation results in MATLAB and the simulation efficiency, this paper discussed the reason for the bias existing between three types of turbulence intensity involved in the whole simulation process: simulated turbulence intensity, setting reference turbulence intensity, and theoretical turbulence intensity. Therefore, a novel spectral correction method of a standard deviation compensation coefficient was proposed. The simulation verification of the correction method was carried out based on the Kaimal spectrum recommended by IEC61400-1 by simulating the uniform turbulent wind field in one-dimensional space at the height of the hub of a 15 MW wind turbine and in two-dimensional space in the rotor swept area. The results showed that the spectral correction method proposed in this paper can effectively optimize the turbulence intensity of the simulated wind field, generate more effective simulation points, and significantly improve the simulation efficiency.


2018 ◽  
Vol 51 (32) ◽  
pp. 51-54
Author(s):  
Yulia A. Dorofeyuk ◽  
Alexander A. Dorofeyuk ◽  
Alexander A. Chernyavskiy

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