Power flow solution of the system with a full-power converter may get lost during low-voltage ride-through （LVRT）. Therefore， the change law of grid equivalent parameters and power flow characteristics during the fault is analyzed， and the law of influence of different system variables on the existence of power flow solution is analyzed qualitatively by numerical calculation considering the control characteristics of the converter. Based on the variation law of the grid equivalent parameters and the real-time calculation of the determinant of the Jacobi matrix of power flow， an active current amplitude limiting and autoregulation method is proposed that only requires the non-fault grid equivalent parameters and the measured voltage at the grid-connected point. The simulation results show that the proposed method can ensure the existence of the power flow solution during LVRT and is conducive to the safe and stable operation of the power system.