This book discusses the fundamental concepts of power grid integration on microgrids of green energy sources. In each chapter, the author presents a key engineering problem, and then formulates a mathematical model of the problem followed by a simulation testbed in MATLAB, highlighting solution steps. The book builds its foundation on design of distributed generating system, and design of PV generating plants by introducing design- efficient smart residential PV microgrids. These include energy monitoring systems, smart devices, building load estimation, load classification, and real-time pricing. The book presents basic concepts of phasor systems, three-phase systems, transformers, loads, DC/DC converters, DC/AC inverters, and AC/DC rectifiers, which are all integrated into the design of microgrids for renewable energy as part of bulk interconnected power grids. Other topics of discussion include the Newton formulation of power flow, the Newton-Raphson solution of a power flow problem, the fast decoupled solution for power flow studies, and short circuit calculations. Focuses on the utilization of DC/AC inverters as a three-terminal element of power systems for the integration of renewable energy sources.