构网型储能逆变器并联系统功频振荡抑制

Parallel System of Grid Forming Energy Storage Inverter Power Frequency Oscillation Suppression

采用构网型储能逆变器(GFI)直接并联可实现对大型关键负荷的供电能力提升与系统冗余,有效提升负载供电的可靠性。然而GFI直接并联时易产生并联环流,尤其是当逆变器采用LCL型输出滤波器时更容易激发功频谐振,严重危害系统的安全运行。通过建立LCL型滤波器的空间状态方程及其数学模型,揭示了GFI并联环流谐振产生机理,并基于逆变器传统电流内环引入由电容电流反馈支路构成的阻尼项,实现对构网型储能并联环流谐振的抑制。最后通过原理样机实验对所提理论分析及控制方案的有效性进行了实验验证。

The use of grid forming inverter(GFI)in direct parallel can realize the power supply capability improvement and system redundancy for large critical loads,and effectively improve the reliability of load power supply.However,it is easy to generate parallel circulation when the GFI is directly connected,especially when the inverter adopts LCL output filter,it is easier to excite power frequency resonance,which seriously endangers the safe operation of the sys-tem.By establishing the spatial equation of state and its mathematical model of LCL filter,the mechanism of parallel circulation resonance of CFI is revealed,and the damping term composed of capacitor current feedback branch is in-troduced based on the traditional current inner loop of the inverter to realize the suppression of the parallel circula-tion resonance of grid forming energy storage.Finally,the effectiveness of the theoretical analysis and control scheme is verified by the experimental prototype.