Abstract: In recent years，the broadband oscillation of power system caused by new energy grid-connected

occurs frequently. As an important part of new energy，photovoltaic power station can't be ignored. In order to

explore the broadband oscillation of photovoltaic grid-connected，a detailed linear mathematical model of

photovoltaic power generation system was established，then the relationship between each oscillation mode and

photovoltaic system was studied by modal analysis，its parameters was optimized according to the specific

influence of photovoltaic power generation system on oscillation mode，and the stability of the system was

improved. Finally，the correctness of mathematical modeling and theoretical analysis was verified by simulation.

      Key words: photovoltaic grid-connected；broadband oscillation；modal analysis；participation factor