具有主动故障穿越能力的光伏逆变器自治控制方法研究

Research on Autonomous Control Method of Photovoltaic Inverter with Active Fault Ride⁃through Capability

文中设计了一种具有主动故障穿越能力的自治智能光伏(photovoltaic,PV)逆变器,所提逆变器具有有功功率和无功功率的解耦控制特性,它可以根据电网状态或电网运行员命令在预期的运行模式之间无缝切换。智能逆变器根据电网状态自动调整其有功和无功功率设定值,在正常电网和故障电网条件模式下分别以最大功率点跟踪(maximum power point tracking,MPPT)和低电压穿越(low voltage ride through,LVRT)模式运行。此外,文中还提出了一种新型自治模型预测控制(autonomous model predictive control,AMPC)方法,以提高智能PV逆变器的运行效率。AMPC包括在线权重因子自动调整和控制目标归一化,以消除传统模型预测控制中所需的试错权重因子设计阶段。最后,通过实验,验证基于AMPC并网智能PV逆变器的性能,实验结果表明,所提基于MPC的智能PV逆变器具有故障穿越、有功和无功功率设定值的自治调整、运行模式之间的无缝转换等优点。

A kind of autonomous intelligent photovoltaic(PV)inverter with active fault through capability is de⁃signed in this paper.The proposed inverter has the decoupling control characteristics of active power and reactive power,and can seamlessly switchover between the expected operating modes in accordance with the state of the pow⁃er grid or the command of the power grid operator.The intelligent inverter automatically adjusts its active and reactive power setting in accordance with the state of the power grid and operates in maximum power point tracking(MPPT)and low voltage ride through(LVRT)modes in normal grid and fault grid conditions respectively.In addition,a novel autonomous model predictive control(AMPC)method is proposed in this paper to improve the operating efficiency of intelligent PV inverters.AMPC includes on⁃line automatic weight factor adjustment and control objective normaliza⁃tion to eliminate the trial⁃and⁃error weight factor design stage required in traditional model predictive control.Finally,the performance of AMPC⁃based grid⁃connected intelligent PV inverter is verified through experiments.The experi⁃mental results show that the proposed intelligent PV inverter based on MPC has the advantages of fault through,autono⁃mous adjustment of active and reactive power setting and seamless conversion between operation modes.