基于傅氏系数自适应组合估计算法的谐波功率实时高精度计算

Real-time high accuracy harmonic power measurement using adaptive Fourier linear combiner

由于常规电量计量装置是基于正弦波设计的,因此在非正弦条件下进行测量必然带来一定的误差。采用改进的傅氏系数自适应组合估计算法进行谐波检测与功率计算,该方法对非同步采样及初始值不敏感,并能实时跟踪电压与电流的变化。实验表明一般经过约1个周期便能对受噪声和衰减直流分量污染的非正弦信号进行实时跟踪,从而精确估计出电压与电流各次谐波的幅值及相位,实现功率的实时高精度计算,并且根据输出误差采用变步长的递推最小均方差LMS(Least Mean Square)自适应算法来改善跟踪性能。最后,给出了在计算机上的仿真测试结果,并将该算法和FFT算法进行了对比分析。仿真证明该算法具有精度高、收敛快且测试结果不受频率变化影响的优点。

As general electric variable measuring device is based on sine wave,so measurement under non -sinusoidal condition has big error certainly. An improved adaptive Fourier linear combiner is used for harmonic estimation and power calculation,which is not sensitive to asynchronous sampling and initial values,and tracks real-timely the variation of voltage and current. Test shows that,the non-sinusoidal signal corrupted with white noise and decaying DC component is real-timely tracked in about a cycle,so that the amplitudes and phases of harmonic components are estimated accurately and the real-time high-accuracy calculation of power is realized. The variable step recursive LMS（Least Mean Square） adaptive algorithm is used to improve tracking performance based on output error. Simulative results on computer are compared with FFT calculation,showing that the proposed algorithm has high accuracy,fast convergence and immunity to frequency variation.