基于自适应采样序列长度的全相位DFT同期并网参数测量

摘要

Photovoltaic/battery microgrid is a typical microgrid structure without rotating regulation system. It requires rigorous standard of synchronized grid connection.Traditional quasi-synchronized grid-connected strategy has been unable to meet its requirements of grid connection.Considering the randomness of distributed generator and the fluctuation of load,an all-phase discrete Fourier transform (DFT) algorithm with adaptive sampling sequence length is proposed to measure the frequency,amplitude and phase angle of the voltage at the point of common coupling(PCC)of photovoltaic/battery microgrid. According to the principle of double-line correcting spectrum method,the calculation formula of frequency,amplitude and phase angle of fundamental signal is deduced based on Hanning double-window all-phase DFT.Simulation results verify that the proposed algorithm can measure the voltage parameter quickly at both sides of PCC under the environment with abundant harmonics,random fluctuation of fundamental frequency and noise.The algorithm has higher accuracy which is suitable for the voltage parameter measurement of photovoltaic/battery microgrid of synchronized grid connection.%光储微网是一种典型的微网结构,没有旋转调节系统,并网要求高,传统的准同期并网策略不足以满足其并网要求.考虑分布式电源的随机性和负荷波动性的特点,提出了自适应采样序列长度的全相位离散傅里叶变换(DFT)算法测量分布式电源和微网公共连接点(PCC)处电压信号的频率、幅值和相位作为同期并网参数.根据全相位DFT双谱线校正原理推导出基于汉宁窗的双窗全相位DFT的基波信号频率、幅值和相位的计算公式.通过仿真验证了算法在谐波含量丰富、基波频率随机波动,以及噪声干扰的环境下能够快速测量出 PCC 处两侧的电压参数,并依然具有较高的精度,适用于光储微网的同期并网的电压参数测量.