New power decoupling strategy for grid-connected inverter under weak power grid

This study analyzes the power coupling in a weak power grid, and designs a novel decoupling method for the coupling power with multi harmonic frequency on the dc bus. By introducing a ratio factor for the dc-bus capacitors, the decoupling ability can be further improved. Moreover, the sliding-mode controller will enhance the system robustness and be adaptive on the varied condition of the power coupling. The proposed control strategy will be effective under the ideal power grid or even the non-ideal power grid. In addition, numerical simulations are provided to verify the effectiveness of the proposed method.