Control strategy for inverters under asymmetric voltage drops considering maximum voltage support capability

In the case of asymmetric faults in the power grid, it is of great significance to allocate the inverter output reasonably to achieve voltage support, which helps reduce the risk of generator tripping and promote the stable operation of the system. This paper proposes a voltage support strategy considering the maximum support level under asymmetric voltage drops. Firstly, the voltage support equation considering zero-sequence voltage is established using the vector method, and the active power deficit point determination formula is proposed. Secondly, considering the voltage drop depth and inverter output limitations, the voltage support level coefficient is used to divide the scenarios, achieving the three control objectives of voltage support, maximum active power output, and reducing voltage imbalance. Finally, the effectiveness and superiority of the support equation and control strategy proposed in this paper are verified through simulations.