基于改进离散傅里叶变换的实时频率和幅值测量算法

精确快速估计频率和幅值对智能电网的监测和运行至关重要;而频谱泄露会严重影响频率和幅值的测量精度。为此提出了一种基于改进离散傅里叶变换(discrete Fourier transformation,DFT)的实时频率和幅值测量算法。首先对考虑频率偏移的DFT算法进行了理论推导。然后为了减弱频谱泄露的影响,对DFT变换结果进行再次计算,给出了频率和幅值计算表达式;为了进一步提高精度,对频率值进行了二次估算。仿真结果表明,该算法能够有效减弱频谱泄露对频率和幅值测量的影响,在不同信号模型下均能得到满足要求的频率和幅值。

Real-Time Frequency and Amplitude Measurement Algorithm Based on Improved Discrete Fourier Transformation

Accurate and fast estimation of frequency and amplitude is crucial for smart grid monitoring and operation, and the spectrum leakage will seriously affect the measurement accuracy of frequency and amplitude. For this reason, a real-time frequency and amplitude measurement algorithm based on improved discrete Fourier transform (discrete Fourier transformation, DFT) is proposed. Firstly, the DFT algorithm considering frequency offset is deduced theoretically. Then, in order to reduce the effect of spectrum leakage, the results of DFT transform are recalculated. The expressions of frequency and amplitude are given. In order to further improve the accuracy, the frequency value is estimated two times. Simulation results show that the proposed algorithm can effectively reduce the influence of spectrum leakage on frequency and amplitude measurements, and can calculate the required frequency and amplitude under different signal models.