光储一体化并网发电系统的惯量阻尼机理分析

The grid-connected power generation system integrated with photovoltaic (PV) and energy storage systems (ESSs) is taken as the research object, and multiple time scales are used in the modeling ideas. Focusing on the main time scale affecting the dynamic characteristics of system frequency-the DC voltage time scale, this paper develops a dynamic model of DC voltage time scale for the analysis of the system inertia and damping characteristics. On the basis of this model, the electric torque analysis method is used to analyze the main factors and their action laws on the inertia effect, damping capacity and synchronization characteristics from the physical mechanism level. The research results show that the dynamic characteristics of the system are determined by its control parameters, structural parameters and steady-state operation point parameters. The inertia effect and synchronization characteristics of the system are respectively affected by the proportional controller and integral controller in the DC bus voltage control loop. The damping capacity of the system is mainly affected by the frequency droop control in the energy storage device. The system dynamic characteristics will not be affected by the PV converter operating in the maximum power point tracking (MPPT) mode. In addition, the system dynamic characteristics are also affected by the structural parameters (such as line impedance and DC bus capacitance), the steady-state operation point parameters (such as the AC/DC bus voltage level of the system) and the steady-state operation power (power angle). Finally, the correctness of the above analysis is verified by the simulation and experiment results.