Photovoltaic power generation system

This utility model provides a photovoltaic power generation system, including a plurality of photovoltaic subsystems, a controller, and a host. The plurality of photovoltaic subsystems connect to each other in series as a first photovoltaic power generation module. Each photovoltaic subsystem includes a photovoltaic module and a smart junction box. The smart junction box includes a voltage sensor and a power line communication transceiver. The voltage sensor is used to measure the voltage of the photovoltaic module. The power line communication transceiver is used to transmit the measured voltage through a power line communication network. The controller constructs a power loop with the first photovoltaic power generation module, and communicates with the smart junction box through the power line communication network. The controller includes a current sensor, which is used to measure the current of the power loop. The host receives the measured current and voltage through a network, determine one of the phot