弱电网中基于调节器重构的多机并网稳定性研究

多逆变器并联并网的方式常见于光伏电站,以满足大规模发电的实际需求。但在弱电网中,由于电网阻抗不可忽略,导致多机并网系统的稳定性受到严重威胁。针对弱电网中多机并网稳定性问题,将弱电网下的三相LCL型并网逆变器作为研究对象,建立多机并网模型,分析了电网阻抗对系统稳定性的影响机理,由此提出一种基于调节器重构的控制策略,调整多机并网系统的零极点分布以提高系统的稳定性,最后研制了两台参数相同的三相LCL型并网逆变器实物平台,通过实验对该控制策略的正确性和有效性进行了验证。

Stability analysis of multi-grid-connected inverters based on regulator reconstruction in weak grid

Multi-grid-connected inverters in parallel are common in photovoltaic power plants to meet the actual needs of large-scale power generation.For the whole system is in weak grid,the stability of the system is seriously threatened because the grid impedance cannot be ignored.For multi-grid-connected in-stability in weak grid,the three-phase LCL-type grid-connected inverter in the background of weak grid was taken as the research object,and the model of multi-grid-connected inverters was established.Influence of grid impedance on system stability was analyzed.Subsequently,to improve the stability of multi-grid-connected inverters system,the control strategy of regulator reconfiguration was proposed to adjust the zero-poles′distribution system.And finally two inverter experimental platforms with the same parameters were built.The experimental results show the correctness and effectiveness of the proposed strategy.