Considering the increase of DC loads and the development of hybrid AC-DC microgrid

a multi-objective optimal sizing model for the grid-connected hybrid AC-DC microgrid is developed for reducing the unit generation cost and converter losses and improving the self-balancing capabilities. Then a control strategy of hybrid AC-DC microgrid for the model is proposed. Based on the data from a practical project

the model is solved by improved non-dominated sorting genetic algorithm(NSGA-Ⅱ). The optimal sizing results of the hybrid AC-DC microgrid under different DC load ratios are obtained

as well as the influence of the increasing DC load ratio on optimal sizing. The comparision of optimal sizing results between the conventional AC microgrid and the hybrid AC-DC microgrid has verified the effectiveness and feasibility of the approach proposed. This work is supported by National High Technology Research and Development Program of China(863 Program)(No. 2015AA050104)and National Natural Science Foundation of China(No. 51207140).