Research on Multi-objective Active Control Strategy of Centralized New Energy under Asymmetric Voltage Sag

Under the asymmetric voltage sag, the centralized new energy faces problems such as lack of coordination of multiple control objectives and high complexity of control strategies, which will 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. Firstly, the influence of grid impedance on voltage is fully considered, and the positive and negative sequence voltage supporting equation is established to realize flexible control of phase voltage. Secondly, several control targets under asymmetric voltage sags based on positive and negative sequence active power and reactive current are established. On this basis, the mutual restraint mechanism of multiple control objectives is analyzed deeply, 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, ipopt optimization algorithm is used to realize multi-objective optimal control of grid-connected inverter under asymmetric voltage sag. The simulation is used to verify the effectiveness of the proposed method in different voltage sag scenarios.