基于变分模态分解与Teager能量算子的谐波/间谐波检测方法

为了提高电力谐波信号中谐波/间谐波的检测精度,提出一种基于变分模态分解(VMD)与Teager能量算子相结合的检测新方法。利用相关系数法来确定VMD算法中的模态分解个数K;采用VMD对谐波/间谐波信号进行分解,得到一系列IMF分量;利用Teager能量算子对IMF分量进行解调分析,能够得到分量的瞬时幅值和频率,同时根据时频图中瞬时频率突变点,可准确定位暂态谐波/间谐波的起止时刻。在信噪比较低的情况下,将集合经验模态分解(EEMD)、VMD分别与Teager能量算子相结合进行谐波/间谐波检测的对比。仿真实验对比表明文中所提方法能将稳态、暂态谐波信号进行有效的分离,同时具有较高的检测精度和较好的噪声鲁棒性。

Harmonic/interharmonic detection method based on variational mode decomposition and Teager energy operator

In order to improve the detection accuracy of harmonics/interharmonics in power harmonic signals, a new detection method based on variational mode decomposition (VMD) and Teager energy operator is proposed. Firstly, the correlation coefficient method is used to determine the modal decomposition number in the VMD algorithm. Secondly, the VMD is used to decompose the harmonic/interharmonic signals to obtain a series of IMF components. Finally, the Teager energy operator is used to make the demodulation analysis of the IMF components. The analysis can obtain the instantaneous amplitude and frequency of the component. According to the instantaneous frequency mutation point in time frequency diagram, the start and end time of transient harmonics/interharmonics can be accurately located. In the case of low signal-to-noise ratio, ensemble empirical mode decomposition(EEMD) and VMD are combined with Teager energy operator for harmonic/interharmonic detection. The simulation experiments comparison show that the proposed method can effectively separate the steady-state and transient harmonic signals, and has higher detection accuracy and better noise robustness.