Research On Grid Connected Technology Of Photovoltaic Power Generation System

Photovoltaic power generation is an important direction of the current utilization of solar energy.The grid connected photovoltaic power station is also the inevitable trend of maximizing the utilization of solar energy.Photovoltaic grid connected power generation brings a series of effects to the distribution network.It is of great significance for the coordinated development of photovoltaic and distribution network to study the related technical problems of grid connected photovoltaic power generation.This paper analyzes the current research status of photovoltaic grid connected power generation technology,expounds the basic working principle of photovoltaic cells,explains the important characteristics of the photovoltaic cells,and explains the structure and classification of the photovoltaic power plant.The related technical problems of photovoltaic grid connected generation include the following aspects:inverter control,maximum power point tracking,low voltage ride through and so on.This paper studies these problems and takes the example of the photovoltaic power station of Taocun as an example,and establishes a simulation model based on the photovoltaic cell,the maximum power point tracking based on the improved perturbation method,the inverter control strategy based on the virtual synchronizer,and the low voltage crossing model based on the smooth switching.Several models are combined to form a photovoltaic grid connected generation system model based on virtual synchronous machine.The grid connected operation characteristics of the photovoltaic power station are simulated,and the influence of the PV grid on the distribution of the power flow and the short circuit current are studied in 2 cases,such as the grid power flow and the short circuit fault current.The output characteristic of inverter based on virtual synchronous machine is simulated,and the reactive power voltage characteristic and active frequency characteristic of inverter are analyzed.The output characteristics of the low voltage crossing control inverter based on the smooth transform are simulated,and the change of the short circuit current and output power of the inverter in the low?voltage crossing process is analyzed.Through the establishment of the related simulation model,the proposed photovoltaic grid connected power generation system based on the virtual synchronizer is simulated.The PV grid connected power system with synchronous machine characteristics can further improve the stability of the power grid operation.