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.