弱电网下LCL并网逆变器新型复合有源阻尼策略

A new compound active damping strategy for LCL grid-connected inverter in weak grid

为抑制并网逆变器LCL滤波器在弱电网中产生的谐振,提出一种基于二阶滤波器的有源阻尼控制策略,对参数进行设计,在减少高精度传感器使用数量、考虑控制延迟的情况下,有效抑制谐振。为了进一步提高由于电网阻抗的增加引起的下降的相位裕度,引入超前相位补偿,构成新型复合有源阻尼策略,有效提高逆变器并入弱电网系统的稳定性和鲁棒性。最后,在MATLAB/Simulink仿真平台和MWINV-9R144三相桥式逆变器实验平台对该策略进行验证。结果表明,当电网阻抗较大时,采用新型复合有源阻尼策略依旧能有效提升逆变系统稳定性,在弱电网中具有较强的适应能力。

In order to suppress the resonance caused by LCL filter,which used in grid-connected inverter in weak grid,an active damping control strategy was proposed based on second-order filter,and the parameters were designed.The resonance could be effectively suppressed by reducing the number of high-precision sensors and considering the control delay.In order to further improve the phase margin caused by the increase of grid impedance,the advanced phase compensation was introduced to form a new composite active damping strategy,which effectively improved the stability and robustness of the inverter incorporated into the weak grid system.Finally,the strategy was verified on MATLAB/Simulink simulation platform and MWINV-9R144 three-phase bridge inverter experimental platform.The results showed that when the grid resistance was large,the new composite active damping strategy could still effectively improve the stability of the inverter system,and had strong adaptability in weak grid.