非理想三相电网的特征信号提取

doi:10.16180/j.cnki.issn1007-7820.2022.04.013

摘要/Abstract

摘要：

当三相电网电压发生畸变或不平衡时,并网系统存在诸多非理想特征信号,例如谐波和负序分量等。针对此类问题,文中提出了一种基于ISDFT的谐波与负序分量提取算法。该算法通过对SDFT传递函数进行重新设计,在保留良好的信号过滤特性同时提高了系统的响应速率,且具有较强的灵活性。实验结果表明,ISDFT能够快速、准确地提取特征谐波及负序分量,且在负载发生突变时具有良好的动态性能。此外,以提取三相电网电压的5次、7次谐波为例,DFT、SDFT、ISDFT提取谐波的效果一致,但ISDFT的响应速率比SDFT快44.56%,比DFT快65.32%。

关键词: 非理想电网, 电网电压畸变, 电网电压不平衡, 改进的滑动离散傅里叶变换, 谐波提取, 负序分量, 正负序分离, 电能质量

Abstract:

When the three-phase grid voltage is distorted or unbalanced, there are many non-ideal characteristic signals in the grid-connected system, such as harmonics and negative sequence components. In view of such problems, this study proposes a harmonic and negative sequence component extraction algorithm based on ISDFT. This algorithm redesigns the transfer function of the SDFT, which retains good signal filtering characteristics while improving the response rate of the system, and has strong flexibility. Experimental results show that ISDFT can quickly and accurately extract characteristic harmonics and negative sequence components, and ISDFT has good dynamic stability when the load changes suddenly. In addition, in terms of the extraction results of the 5th and 7th harmonics, DFT, SDFT, and ISDFT have the same effect of extracting harmonics, but the response rate of ISDFT is 44.56% faster than SDFT and 65.32% faster than DFT.

Key words: non-ideal grid, grid voltage distortion, grid voltage imbalance, improved sliding discrete Fourier transform, harmonic extraction, negative sequence component, positive and negative sequence separation, power quality

中图分类号:

TN710.1

袁庆庆,蒋敏,杨玉美. 非理想三相电网的特征信号提取[J]. 电子科技, 2022, 35(4): 78-86.

Qingqing YUAN,Min JIANG,Yumei YANG. Characteristic Signal Extraction of Non-Ideal Three-Phase Grid[J]. Electronic Science and Technology, 2022, 35(4): 78-86.

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谐波提取方法	5次谐波提取时间	7次谐波提取时间
DFT	251.41	228.93
SDFT	157.28	143.22
ISDFT	87.19	78.62

谐波提取方法	5次谐波占比	7次谐波占比
DFT	19.96	14.25
SDFT	19.96	14.25
ISDFT	19.97	14.27