Research On Digital-physical Hybrid Simulation Technology For Grid-connected Photovoltaic Power Station

As China’s photovoltaic power generation technology becomes more and more mature,the scale of photovoltaic power stations is also expanding,and it is basically connected to the grid.Therefore,the grid-connected photovoltaic power station will also bring more challenges,because the actual photovoltaic power generation system is poor in economy and large in size,it is inconvenient to directly use it as a research target.In order to study the operation characteristics of grid-connected photovoltaic power station system,it is very important to find suitable and effective simulation methods.The digital physical hybrid simulation technology combines the advantages of pure digital simulation and pure physical simulation to open up a new way for the development of simulation.The simulation method can not only save the cost but also show the operating characteristics of the system.It is an effective means to study the grid-connected photovoltaic power generation.This paper introduces the research status of photovoltaic power generation and summarizes the research status of digital physics hybrid simulation.The structure of photovoltaic power generation system is deeply studied,the mathematical model of photovoltaic power station is established,and the conversion principle,efficiency and output characteristics of photovoltaic power generation are studied in detail.The principle of PHIL system of PV power station is analyzed in detail,and the simulation model of PV power station is built,and the model is segmented by voltage source ITM interface algorithm.Simulation results demonstrate the effectiveness of the proposed segmentation method.On this basis,a converter is used instead of a controlled source on the grid side to simulate the digital physical hybrid simulation experiment of a grid-connected photovoltaic power station.Three interface algorithms are summarized,and then the principles and application scenarios of these three interface algorithms are derived in detail and the accuracy of waveform data is compared.The ITM interface algorithm is improved,and the interface algorithm with additional resistance is obtained,which can make the system data more accurate.The correctness of the method is verified by the simulation results,which provides a reliable basis and data source for the PHIL simulation of PV power station.The general real-time simulator designed by ourselves and the open converter system as an interface device are introduced.Its principle and function are explained in detail.Based on the universal real-time simulator and the open converter system,the digital physical hybrid simulation experiment platform of photovoltaic power station is designed.The photovoltaic power station model is designed in the digital subsystem,and the laboratory power grid and some equipment are designed as the physical subsystem.The open converter system realizes data exchange between the two.Through the digital physical hybrid simulation platform of photovoltaic power station connected to the grid,the grid-connected experiment of photovoltaic power station and the tracking experiment of the output active power of photovoltaic power station are carried out,and the error comparison of voltage and current data before and after the interface algorithm is improved is carried out,which verifies the accuracy and effectiveness of the digital physical hybrid simulation technology of photovoltaic power station studied in this paper.