METHOD AND DEVICE FOR CONTROLLING LOW VOLTAGE RIDE THROUGH OF PHOTOVOLTAIC GRID-CONNECTED INVERTER

摘要

A method and device for controlling the low voltage ride through (LVRT) of a photovoltaic grid-connected inverter, the control method comprising: determining whether the voltage value of a power grid is less than the upper limit of a low voltage value, and not greater than the lower limit of the low voltage value; if determining that the effective voltage value of the power grid is less than the upper limit of the low voltage value and greater than the lower limit of the low voltage value, then controlling an active current value outputted by an inverter to be equal to a target active current value, and an outputted inactive current value to be equal to a target inactive current value, such that the comparative difference value between the total current outputted by the inverter in an LVRT state and a current outputted in a normal state is less than a preset value. The method and device solve the low stability problem caused by ignoring the control of current waveform and amplitude during inverter LVRT control, so that the total current has little change before and after a voltage dip, thus supporting and stabilizing a power grid.