The invention discloses a low-
voltage ride through control strategy for a grid-connected
photovoltaic power generation system capable of providing the reactive support. The strategy comprises the steps of control over a preceding-stage DC /
DC converter and control over a backward-stage grid side
inverter. When grid faults occur, the backward-stage grid side
inverter is controlled to provide needed reactive power for a
power grid according to the
voltage drop depth of the
power grid; the feed-forward compensation dosage reflecting photovoltaic array output power and direct-
current voltage fluctuation is added into a direct-current side
voltage control ring of the
inverter, and therefore over-voltage of the direct-current side of the inverter is reduced in the fault occurring process; a controller of the preceding-stage DC /
DC converter controls a photovoltaic array to output active power according to the
voltage drop depth and the rated capacity of the inverter, so that unbalanced energy in a
photovoltaic system when the faults occur is reduced, and the purpose of reducing over-current and over-voltage in the
photovoltaic system is achieved. According to the strategy, no hardware device is additionally arranged, the response speed is high, realizing is simple, the low-voltage ride through capacity of the
photovoltaic system can be effectively improved, the reactive power can be provided for the
power grid, and the voltage
recovery of the power grid is supported.