| 摘要: |
| 讨论线性调频Z变换(CZT)的频率误差原因。指出CZT误差受采样时间和信号初相位的影响,且当信号相位差90°时两信号的CZT频率关于真实值近似对称,并提出改进的正交平均CZT算法。分别对单频信号和电力仿真信号进行仿真实验。结果表明,改进算法的频率精度比传统CZT的精度提高了至少20倍,有效提高了电网频率的分析精度。 |
| 关键词: 电力信号 基波频率 线性调频Z变换 正交平均 初相位 采样时间 |
| DOI：10.3969/j.issn.1673-5005.2013.06.027 |
| 分类号:TM 935.2 〖HTH〗 |
| 基金项目:“十二五”国家科技重大专项资助项目(2011ZX05024-002-009) |
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| Improved CZT algorithm for improving power system frequency detection accuracy |
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LIU Guang-fu, XIA Yun, ZHANG Shan
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(College of Information and Control Engineering in China University of Petroleum, Qingdao 266580, China)
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| Abstract: |
| Causes of frequency measurement errors in chirp-Z transform (CZT) were discussed. It is shown that CZT errors are influenced by sampling time and signal initial phase, and the CZT frequencies of two signals with 90° difference in the initial phase are approximately symmetrical around the true frequency. An improved algorithm named orthometric average CZT was developed. Experiments on simulated single tone signal and simulated power signal show that the new algorithm yields about 20times smaller error bounds than the conventional algorithms, therefore greatly improves the accuracy of frequency analysis in power signal. |
| Key words: power signal fundamental frequency chirp-Z transform orthometric average initial phase sampling time |
