Inverter and main controller for photovoltaic power generation system, and operating method for photovoltaic system

A primary controller of a photovoltaic power generation system, the primary controller comprising:

• a communication unit configured to transmit a control signal to a plurality of module-level power electronics (MLPE) devices and receive a monitoring signal from the plurality of MLPE devices;
• and
• a processor configured to determine whether an abnormal situation occurs in the photovoltaic power generation system, gradually ramp down an output voltage of one or more MLPE devices among the plurality of MLPE devices, and induce a gradual ramp-down of a maximum power point tracking (MPPT) control voltage of an inverter, based on the output voltage of the one or more MLPE devices.