Grid connected DC distribution system for efficient integration of sustainable energy sources

In this paper, some of the aspects related to the design and implementation of grid connected DC microgrids are investigated. A prototype system has been designed and implemented to address these aspects. The described system is dependent mainly on sustainable energy sources. Hence, a special care has been given to dealing with these kinds of sources while designing different components of the system. Certain features had to be maintained in the system in order to assure efficient integration of different sources, efficient and reliable load-feeding capability and full controllability of voltage and power flow among various buses in the system. Moreover, a fully controlled rectifier has been designed to tie the DC grid with the AC one. A vector decoupling controlled sinusoidal pulse width modulation (SPWM) technique has been used to allow the designed rectifier to maintain a constant output voltage while being able to control the active and reactive power drawn from the grid independently. Both simulation and experimental results verify the validity of the proposed system.