Comparison between DC and AC microgrid systems considering ratio of DC load

Due to recent growth of small-scaled distributed generators such as PV in demand-side, the local demand and supply system that called MG, becomes real possibility. MGs would be equipped with energy storage systems such as a battery. Since PVs and batteries primitively work with DC, advantages of DC supply system over AC supply might be emphasized. This paper proposes an algorithm for optimal design of MG including the selection of AC or DC supply system. This paper also qualitatively discusses the advantage of MG with DC supply, named DCMG through case studies for residential customer assuming four types of home appliances; constant load such as a refrigerator, lighting, air conditioner and the others. The results of case studies show the economic advantage of DCMG over ACMG.