直流电容同步控制的低频振荡分析及阻尼提升策略OA

Grid-forming converters based on DC capacitor synchronization show favorable application potential in the photovoltaic system.However,the introduction of the DC voltage control loop makes low-frequency oscillation issues more pronounced.On this basis,this paper firstly develops a small signal stability analysis model for DC-link capacitor synchronization control.Root locus analysis is then employed to investigate the influence of control parameters on system stability,revealing that increasing the proportional and integral gains of the DC voltage loop leads to significant increases in the imaginary and real parts of the eigenvalues respectively.Furthermore,the damping torque analysis method is used to examine the components of damping and synchronizing torques in the DC-link capacitor synchronization control,thereby explaining the mechanism of negative damping formation and revealing the underlying influence of key parameters.The analysis shows that the integral gain introduces a negative damping torque component in the grid-forming converter.Finally,the stability conditions of a system consisting of multiple parallel-connected grid-forming converters are analyzed based on the damping torque method,and a damping enhancement strategy is proposed accordingly.Simulation results validate the effectiveness of both the parameter analysis and the proposed strategy.