A Tutorial on Current Controlled DC-DC Converter used in Microgrid System

A microgrid system is a small-scale power generation system which can connect to other utility grids or operate independently as a stand-alone system. With the advancement in power electronics, DC/DC converters are widely used in remote data communication, manufacturing and aerospace industry, and energy field. In this tutorial paper, we represent an entire microgrid system to explain different operational modes of DC/DC converters. DC/DC converters can be classified as a boost converter, buck converter, and bi-directional converter. We represent a simple structure bi-directional DC/DC converter connected to the DC bus and battery storage to achieve two-directional energy flow: from the battery to DC bus or DC bus to the battery. With a simple control scheme, the bi-directional DC/DC converter operates in two modes: buck and boost. In discharge mode, the bi-directional DC/DC converter acts as a boost converter and power flows from the battery to DC bus, whereas in charge mode, the bi-directional DC/DC converter acts as a buck converter and transmits energy from DC bus to the battery. Also, a stand-alone photovoltaic power system is connected to the battery to supply power for the battery storage. The entire microgrid system is utilized to supply power for the DC load in a sustainable way. The proposed model is implemented and simulated on MATLAB and effective results are demonstrated.