| 引用本文: | 许 珉,王 玺,程凤鸣.基于加Hanning窗递推DFT算法的测频方法[J].电力自动化设备,2010,(11): |
| XU Min,WANG Xi,CHENG Fengming.Frequency measuring based on Hanning windowed recursive DFT algorithm[J].Electric Power Automation Equipment,2010,(11): |
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| 摘要: |
| 常用递推离散傅里叶变换（DFT）方式动态计算频谱，根据相位计算结果实时计算电网变化的频率，动态调整测量控制装置的采样频率实现同步采样。但由于截断信号会产生频谱泄漏，使得相位和频率计算结果有一定误差，采用该方法跟踪频率，实时计算电网变化的频率速度较慢。为提高频率跟踪计算速度，对加Hanning窗递推DFT算法计算频率进行了研究，利用2次加Hanning窗递推DFT求出工频基波相位经过1个工频周期后的相位变化量，再利用该变化量求出对应频率的变化量。采用加窗递推DFT有效减小了频谱泄漏的影响，提高了相位差的计算精度和速度，从而可以提高频率的计算精度和速度。该方法简单，易于实现，计算量较小，频率跟踪速度快。 |
| 关键词: 相位差校正法 递推DFT算法 Hanning窗 频谱泄漏 频率 |
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| Frequency measuring based on Hanning windowed recursive DFT algorithm |
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XU Min,WANG Xi,CHENG Fengming
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1.School of Electrical Engineering，Zhengzhou University，Zhengzhou 450002，China;2.Luohe Power Supply Company，Luohe 462000，China
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| Abstract: |
| Recursive DFT（Discrete Fourier Transform） is normally used to dynamically calculate the frequency spectrum. According to the phase calculation，the power network frequency change is calculated to real -timely adjust the sampling frequency of measurement control device for synchronization. The spectral leakage caused by the truncated signals results in frequency calculation error and slows frequency tracking. A Hanning windowed recursive DFT method is introduced. The phase change of fundamental frequency in a frequency cycle is calculated by using Hanning windowed recursive DFT twice，with which the corresponding frequency change is calculated. The use of windowed recursive DFT effectively reduces the impact of spectral leakage and improves the accuracy and speed of phase change calculation. The proposed method has low computational complexity and fast frequency tracking speed，simple and easy to implement. |
| Key words: phase difference correction method recursive DFT algorithm Hanning window spectral leakage frequency |
