基于Hilbert变换和预设旋转频率的无锁相环电网同步基准正弦信号检测方法

Reference Sinusoidal Signal Detection Method of Gird Synchronization without Phase-Locked Loop Based on Hilbert Transform and Pre-Set the Rotation Frequency

新能源发电并网过程中,电网同步基准正弦信号检测是并网关键之一,特别是在电网不平衡、畸变、频率波动和频率偏移等复杂工况下,对电网同步基准正弦准确检测造成较大干扰。为此提出一种基于Hilbert变换和预设旋转频率的无锁相环电网同步基准正弦信号检测方法。该方法通过预设同步旋转频率进行特定次频率分量正、负转换,然后运用Hilbert变换的幅相特性和一定的运算消除正序谐波分量、基波负序分量和负序谐波分量。所提方法能在复杂的工况下准确提取电网同步基准正弦信号,理论和实验验证了该方法的有效性和可行性。

In the process of grid-connected new energy generation system, it is important to detect the reference sinusoidal signal of grid synchronization, especially under power grid imbalance, distortion, frequency fluctuation, frequency offset and other complex grid conditions. A method without phase-locked loop that extracts reference sinusoidal signal of gird synchronization is proposed in this paper based on the Hilbert transform and pre-set rotation frequency. First, This method transforms the positive and negative frequency components at specific time with presetting synchronous rotation frequency, eliminates the positive sequence, fundamental negative sequence and negative sequence harmonic components using the amplitude and phase characteristics of Hilbert transform and certain operations. The proposed method can accurately extract the reference sinusoidal signal of the grid synchronization under complex grid conditions, which is verified through theory and experiment.