Abstract: A photovoltaic power generation system includes a single-stage inverter, an anti-backflow circuit, a photovoltaic string, and a coupling capacitor. The anti-backflow circuit is connected to one input end of the single-stage inverter, one output end of the photovoltaic string is connected to the other input end of the single-stage inverter, and the other output end of the photovoltaic string is connected to the anti-backflow circuit. The photovoltaic string includes a buck optimizer and a photovoltaic panel. The anti-backflow circuit is configured to prevent a backflow current from flowing back to the photovoltaic string. The coupling capacitor is connected in parallel to two ends of the anti-backflow circuit and is configured to transmit a signal between each buck optimizer in the photovoltaic string and the single-stage inverter, to control backflow of the backflow current when the anti-backflow circuit fails.