不对称电压跌落下分布式新能源多目标主动控制策略研究

A multi-objective active control strategy for distributed generation under asymmetric voltage sag

在电网电压不平衡跌落下,分布式新能源面临多控制目标缺乏协调、控制策略复杂等问题,严重情况下导致切机,影响电网稳定运行。对此,充分考虑电压跌落场景,提出了一种不对称电压跌落下新能源多目标主动控制策略。首先,充分考虑电网阻抗对于电压的影响,建立了不对称电压跌落下的逆变器正负序电压支撑方程,实现了对相电压的灵活控制。其次,提出了不对称电压跌落下多个新能源控制目标,并建立了基于正负序有功和无功电流的控制目标方程。在此基础上,深入分析多控制目标相互制约机理,并根据电压跌落程度优化控制目标,构建不同场景下的目标函数与约束条件。最后,利用Fmincon优化算法,实现并网逆变器在不对称电压跌落下的多目标优化控制。利用Matlab/Simulink仿真平台,验证了该方法在不同电压跌落场景下的有效性。

Under asymmetric voltage sag,distributed generation faces problems such as lack of coordination of multiple control objectives and high complexity of control strategies.These can lead to disconnection in serious cases and affect the stable operation of the power grid.Thus,a multi-objective active control strategy for DG is proposed considering voltage sags.First,the influence of grid impedance on voltage is fully considered,and the positive and negative sequence voltage supporting equation under asymmetric voltage sag is established to realize flexible control of phase voltage.Second,several control targets under asymmetric voltage sag based on positive and negative sequence active power and reactive current are established.The mutual restraint mechanism of multiple control objectives is analyzed,and the control objectives are optimized according to the voltage sag scenarios,and the objective function and constraint conditions in different scenarios are constructed.Finally,the Fmincon optimization algorithm is used to realize multi-objective optimal control of a grid-connected inverter under asymmetric voltage sag.Matlab/Simulink is used to verify the effectiveness of the proposed method in different voltage sag scenarios.