Coordinated control of series compensation link and bus interface converter in the AC-DC hybrid microgrid

To improve the fault ride-through capability and power quality of a hybrid microgrid (HMG), a series compensation link (SCL) is inserted between an AC-DC HMG and a utility grid, which forms a new HMG topology. Correspondingly, a decoupling coordinated control strategy for the SCL and a bidirectional AC-DC interlinking converter (BIC) is proposed based on a small signal model of the entire system and the principle of voltage regulation. The interferences between the SCL and the BIC due to the coupling of control factors are eliminated by the series and parallel decoupling methods that adopt additional current closed-loop control and output voltage feedforward control, respectively. The proposed HMG topology and strategy can ensure the realization of the predesigned functions of dual converters and avoid frequent switching between the grid-tied mode and the island mode, which improves the fault ride-through capability and power quality. Finally, the effectiveness of the proposed approach is verified by simulations and experiments.