The evolution of global energy industry has promoted the transformation of power electronics in the power system.The proportion of synchronous machines in renewable-rich power system is low,and the system shows low iner-tia and weak damping characteristics,causing a series of operational issues.The grid-forming converter is a voltage source in essence,which can actively construct voltage frequency,provide inertia for the system,consequently,improve system stability.It is an effective means to improve the power ability of new energy and has become a research hotspot in recent years.Starting from the operational issues of renewable-rich power system,this article summarizes the implemen-tation principles and internal connections of grid-forming control strategies such as droop control and virtual synchronous generator control,and establishes a unified mathematical model for grid-forming strategies;by comparing the voltage and frequency construction principles of synchronous generator and grid-forming converters under steady-state conditions,the physical essence of grid-forming converters is revealed.The characteristics of grid-forming converters are explained from the perspectives of voltage and frequency construction,inertia damping support,synchronization mechanism,etc.,providing theoretical reference for the stability and control of grid-forming converters.
关键词
构网型控制/新能源并网/变流器/物理本质/电压频率构建/稳定控制/电力电子化电力系统
Key words
grid-forming/grid connection/converter/mechanism and characteristics/voltage and frequency construction/stability control/power-electronized power system
维普
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