计及低电压穿越电流限幅的VSG与SVG混合系统无功协调控制策略OA

To address the challenges of current over-limitation and limited voltage support capability in grid-forming energy storage converters during low-voltage ride-through(LVRT)under grid fault-induced voltage sags,this study proposes a coordinated reactive power control strategy for a hybrid Virtual Synchronous Generator(VSG)and Static Var Generator(SVG)system incorporating an LVRT current limiting strategy.Firstly,it introduces a typical control methodology of VSG,and conducted an analysis on the transient characteristic power-angle curves under different levels of grid voltage sags.Subsequently,it developed an improved q-axis priority current limiting strategy by modifying the existing approach,where the active power reference value is proportionally reduced according to the diminished d-axis current,resulting in an adaptive active power reference q-axis priority current limiting approach.Furthermore,to overcome the restricted voltage support capacity of standalone VSG during severe grid voltage sags,a collaborative control framework integrating SVG with VSG is established,accompanied by a reactive power allocation strategy.The strategy redesigns the reactive power control loop of VSG with SVG priority for reactive power compensation as a prerequisite,while introducing the current limiting mechanism of SVG and designing the specific cooperative control process for the hybrid system.The effectiveness of the proposed methodology is conclusively validated through Simulink simulation results.The experimental results demonstrate that the proposed current limiting strategy effectively restricts the output current,while the hybrid system control methodology significantly enhances voltage recovery performance during grid voltage sags.