Control strategy of the bi-directional converter for hybrid AC/DC microgrid

Control strategy of the AC/DC bi-directional converter(ADBC) in hybrid AC/DC microgrid plays a crucial role for stable operation and power distribution of the whole microgrid. A novel ADBC control strategy is proposed in this paper. In grid-connected mode, ADBC adopts improved droop control to maintain stable DC bus voltage, which ensures maximum efficiency of renewable energy in DC microgrid. In islanding mode, ADBC adopting improved droop control ensures the rational power allocation between AC and DC microgrid, improving the stability of the whole system. The control strategy both reduces the ADBC operation loss in the two modes. And the same control structure applied in the two modes avoids complex mode-switching simply by changing the power reference. Finally, simulation results based on PSCAD /EMTDC for hybrid AC/DC microgrid in grid-connected mode and islanding mode show that the proposed control strategy is correct and efficient.