| The implementation of the "carbon peak,carbon neutral" national energy strategy has promoted the reshaping of the energy structure,allowing more clean,renewable new energy to enter the grid,thus promoting economic development.With the continuous popularization of new energy,building a comprehensive and sustainable power system will bring unprecedented changes to the traditional power system.Microgrid is the key to achieve this goal,which will greatly promote the process of power transformation.With the continuous rise of new energy generation,the scale of microgrid is also expanding,which brings unprecedented challenges to the security and reliability of power system.Therefore,the development and extension of hybrid microgrid applications can overcome the limitations of traditional generator sets,promote the wide application of renewable energy,and ensure the stable operation of the entire power system.In this paper,the mathematical models of distributed power supply,load and energy storage will be discussed in depth according to the topology of microgrid,and the energy interaction under different modes will be analyzed according to the operation requirements of microgrid,the operation control strategy will be improved,and a new joint control method of connection converter will be proposed.The Virtual Synchronous Generator(VSG)is combined with fixed DC voltage,and the system is analyzed and modeled,and the key parameters are analyzed.The model of source-netcharge-storage microgrid is built in MATLAB/Simulink.Secondly,in order to further meet the needs of stable operation of the sourcenetwork-charge-storage microgrid,the control system is improved to achieve seamless switching between and off the grid.The existing problems in the off-grid switching process are analyzed,and the traditional Phase-locked Loop(PLL)based presynchronization control is studied,and on this basis,a PLL free pre-synchronization control mode is designed for contact converters and AC energy storage to meet the seamless switching requirements of microgrids.It also simplifies the system.The proposed pre-synchronization control strategy is simulated and verified in MATLAB/Simulink.Finally,a real-time simulation platform is built based on UREP300,a real-time simulator independently developed by the laboratory.The source-network-chargestorage microgrid system is partitioned through core processing,and the ideal transformer model(ITM)method is adopted to realize data interaction between the segmentation interfaces.At the same time,the observation and control platform is built on the host computer.Finally,real-time simulation is carried out for different working conditions to verify the feasibility of the built system. |
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