Small Signal Modeling And Stability Analysis Of Inverter-connected Microgrid

With the rapid development of renewable energy power generation and micro-gridtechnologies, micro-grid modeling and stability analysis theory, as an important theoreticalbasis to optimize micro-grid system and its control methods, have attracted more and moreattention. Modeling and stability analysis methods for high-frequency inverter basedmicro-grid are not mature, and the research in this area is of great significance for thepromotion of micro-grid applications. Exploratory research of inverter type micro-gridsystem-level modeling and stability analysis is carried out in this paper.The model of micro-grid was analyzed in depth in this paper. In allusion to thesmaller bandwidth of the network and the inverters, as well as the dynamic characteristicsof loads, the small-signal stability analysis model of the distributed generationinverter-connected micro-grid has been established, which can be used to more effectiveanalyze the stability and dynamic performances of inverter-connected micro-grid. First,multiple voltage source inverters were established in the model, each inverter has a powerouter loop and current inner loop feedback control. The power loop uses the traditionaldroop method, including the network and load small-signal dynamic sub-model. Bycalculating the eigenvalues of the above model, the small-signal stability of micro-gridcould be analyzed intuitively.Further analysis of the influence of the micro-grid-connectedinverter power control system in both low and high frequency mode parameter variationsand load change has on stability and trends of the entire system is given, which summedup the general rules affecting the stability of the micro-grid. Distributed network structureand impedance characteristics are specially considered and the inverter-type micro-gridsystem-level small-dynamic model is established in this paper. Research and analysis oftypical parameter’s influence on the system stability was done through model eigenvalueanalysis, which laid the foundation for system optimization.To verify the micro-grid model and the effectiveness of the system stability analysisin the proposed theory, the simulation has been operated by using matlab.