This paper aims to investigate the subsynchronous oscillation of photovoltaic grid-connect-ed power generation system based on LCL filter.The study works by establishing a small signal model ac-cording to the mathematical model of each link in the photovoltaic power generation system;obtaining the oscillation types in the system through the eigenvalue analysis method and calculating the participating factors of each oscillation mode;and using PSCAD/EMTDC to build a simulation model of photovoltaic grid-connected power generation system,proving the accuracy of the conclusions obtained in this paper.The results show that there are 2 subsynchronous oscillation modes and 1 low-frequency oscillation mode in the system.Each mode is mainly generated by the interaction between photovoltaic power station and AC power grid power electronics,and the dominant factors are the system series compensation,LCL filter parameters and control parameters inside the phase-locked loop.Moreover,with the increase of phase-locked loop parameters,the oscillation of the system becomes more serious.The increase of inductance parameters in the filter leads to the divergence of the system and the increase of material costs.The larger the degree of series compensation,the worse the stability of the system is,and the more likely it is to cause subsynchronous oscillation.
维普
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