ELECTRIC ENERGY BACKWARD-FLOW CONTROL METHOD, CONVERTER, AND PHOTOVOLTAIC POWER GENERATION SYSTEM

This application provides a converter and a power backfeed control method that are applied to a photovoltaic power generation system. One end of the converter is connected to at least one photovoltaic string, and another end of the converter is connected to a power grid. Each photovoltaic string corresponds to one string number. The power backfeed control method includes: controlling, according to a backfeed instruction, the converter to enter a backfeed mode, where in the backfeed mode, the converter can transmit energy of the power grid to a selected photovoltaic string with a corresponding number; determining a backfeed control voltage according to the backfeed instruction, and determining a voltage limit in a process of determining the backfeed control voltage; determining an actual backfeed voltage based on the backfeed control voltage and the voltage limit, where the actual backfeed voltage is a smaller one of the backfeed control voltage and the voltage limit; and controlling the converter to output the actual backfeed voltage to the selected photovoltaic string, to enable the selected photovoltaic string to generate an electroluminescent effect. This application can improve detection efficiency of the photovoltaic string, and reduce a power loss of the photovoltaic power generation system.