The invention discloses a
low voltage ride through control method and device of a photovoltaic grid-connected
inverter, and is designed to solve the problem of poor ride through stability caused by neglecting control of a current waveform and an amplitude when the
low voltage ride through control is performed on the
inverter in the prior art. The method includes the steps as follows: step S1, whether a
voltage value of a
power grid is smaller than the upper limit of a
low voltage value is judged, if the
voltage value of the
power grid is smaller than the upper limit of the low
voltage value, the step S2 is executed, and otherwise, the
inverter is controlled to work normally; step S2, whether the voltage value of the
power grid is not more than the
lower limit of the lower value is judged, if the voltage value of the power grid is not more than the
lower limit of the lower value, the inverter is controlled to stop working, and otherwise, an active power current value output by the inverter is controlled to be equal to a target active power current value and the output reactive power current value is equal to a reactive power current value; and a comparison difference value of a
total current output by the inverter and a current output by a photovoltaic grid in a
normal state is smaller than a preset value. The change of total currents before and after
voltage sag is small by controlling an active power current and a reactive power current of the inverter, so that the functions of supporting and stabilizing the power grid are realized.