Research On Active Power Quick Response Of Photovoltaic Power Plant Based On Hybrid Energy Storage

In recent years,the penetration rate of photovoltaic power generation has been increasing,the proportion of power electronic converters in power systems has continued to increase,the reserve capacity and moment of inertia in power systems have been greatly reduced,and traditional frequency stability control research is insufficient to support the safety of photovoltaic high penetration power systems stable operation.In this context,in order to enhance the rapid response of photovoltaic power generation systems to grid frequency change,the virtual synchronous generator(VSG)technology is introduced,and the hybrid energy storage with various types of energy storage coordinated with each other is used as a frequency modulation resource.The rapid response model of active power of photovoltaic power station based on hybrid energy storage is established to achieve frequency stability control.First,the topological structure of a photovoltaic power generation system model based on hybrid energy storage is studied.Considering the corresponding relationship between the active power output characteristics of photovoltaic power generation systems and the storage and discharge characteristics of lithium batteries and supercapacitors,a hybrid energy storage system model based on parallel connection of DC-side dual converters is established.Based on this,the mathematical model and control strategy of DC/DC converter and DC / AC inverter of hybrid energy storage system are studied,and build the topology of photovoltaic power generation system based on hybrid energy storage.Secondly,the control strategy of photovoltaic virtual synchronous generator(PV-VSG)based on hybrid energy storage is studied.Aiming at the frequency change scenario of a high percentage of photovoltaic power systems,a method for controlling active power standby mode of a photovoltaic power generation system based on virtual synchronization is proposed,and a rapid active power response model of the photovoltaic power generation system is established;Considering the participation of hybrid energy storage system in frequency regulation,the frequency response model of photovoltaic power generation system based on Hybrid energy storage system is proposed.The hybrid energy storage power is allocated by wavelet packet decomposition algorithm,and the hybrid energy storage system coordinated control strategy is adopted to prevent the hybrid energy storage system power from exceeding the limit.The effectiveness of the proposed control strategy is verified by the simulation analysis.Finally,the dynamic collaborative control strategy of photovoltaic virtual synchronous generator based on hybrid energy storage is studied.Considering the uncertainty of the photovoltaic power generation system,aiming at the problem of the second frequency drop when the photovoltaic output power is lower than the reference power,the dynamic collaborative control strategy of the hybrid energy storage system to coordinate the photovoltaic power generation system is studied.The characteristics of the charging state change of the hybrid energy storage system are proposed.The charge state recovery control strategy of the hybrid energy storage system is proposed.The feasibility and effectiveness of the PV-VSG dynamic collaborative control strategy based on the hybrid energy storage are verified through simulation.