采用改进支持向量机和复小波变换的谐波及间谐波测量方法

Harmonic and Inter-harmonic Measuring Method Using Improved Support Vector Machnie and Complex Wavelet Transform

为给谐波、间谐波治理提供准确依据,提出了基于改进型支持向量机和可调窗复连续小波变换相结合的高精度谐波、间谐波测量方法。通过合理优化预设模型的准确性,构造改进型支持向量机对整个测量频带进行初步扫频,以较小的计算量一次性获取谐波、间谐波分量的个数并初步测量其频率。根据改进型支持向量机提供的频谱分布情况,对各个分量跟踪配置复连续小波对应的带通滤波器,逐个精确测量其频率和幅值。通过适当调整各个复小波窗函数的带宽参数,构造频窗互不交叉的复带通滤波器来抑制频率邻近分量之间的干扰,同时能在非同步采样条件下有效抑制基波频率波动对测量精度的影响。仿真结果表明,该方法能够准确测量谐波、间谐波分量的频率、幅值和相位,具有测量精度高、计算量小、抗噪性能好等优点。

We developed a new harmonic detection method,namely,harmonics and interharmonics detecting method based on the improved SVM-complex wavelet transform.Through optimizing the accuracy of presupposition model,the improved SVM was applied to get the number and approximate frequency of harmonics and interharmonic by scanning the whole frequency band with low calculation amount.According to the spectrum supplied by improved SVM,complex wavelet transform was applied to detect harmonics and interharmonics＇ accurate frequency and amplitude of each component through configuration of complex band pass filter（CBPF） corresponding to CWT.Moreover,mutually uncrossed CBPF was constructed to inhibit interference of adjacent frequency component through the adjustment of bandwidth parameter of CWT,avoiding impair on measuring accuracy coming from asynchronous sampling.The results indicate that the interharmonic detecting method,based on improved support vector machines—complex continuous wavelet transform algorithm,can measure the frequency,amplitude and phase of harmonics and interharmonics,and has the advantages of high detecting accuracy and low calculation amount.