基于双窗全相位FFT的变流器阻抗高精度辨识新方法

New High Precision Identification Method for Converter Impedance Based on Double-window All-phase FFT

为了提高变流器阻抗辨识精度,提出将布莱克曼双窗全相位快速傅里叶变换算法应用于并网变流器输出阻抗高精度辨识之中。首先,建立了dq坐标系下的三相并网变流器的dq阻抗模型;其次,基于原理分析论证了所提方法具有优良的频谱泄漏抑制性能以及较强的抗噪能力,特别适合于在施加小扰动信号背景下非线性特性较强的并网变流器输出阻抗的高精度辨识,并给出变流器阻抗辨识流程;最后,通过仿真试验,验证了方法的优越性。基于布莱克曼双窗全相位快速傅里叶变换的阻抗辨识方法,相比传统方法能以更高的精度辨识出变流器输出阻抗。

In order to improve the impedance identification accuracy of the converter,the Blackman double-window all-phase fast Fourier transform algorithm was proposed to be applied to high-precision identification of the output impedance of the grid connected converter.Firstly,the dq impedance model of the three-phase grid connected converter in the dq coordinate system was established;secondly,based on principle analysis,it was demonstrated that the proposed method has excellent spectrum leakage suppression performance and strong noise resistance,which was particularly suitable for high-precision identification of output impedance of grid connected converters with strong nonlinear characteristics under the background of small disturbance signals.The identification process of converter impedance was also provided;finally,the superiority of the method was verified through simulation experiments.The impedance identification method based on Blackman double-window all phase fast Fourier transform can identify the output impedance of the converter with higher accuracy compared to the traditional methods.