DESIGN AND CONTROL OF MICRO-GRID FED BY RENEWABLE ENERGY SOURCES

Abstract

This project presents a control of a Micro-Grid at an isolated location fed from wind and solar based hybrid
energy sources. The machine used for wind energy conversion is doubly fed induction generator (DFIG) and a battery
bank is connected to a common DC bus of them. A solar photovoltaic (PV) array is used to convert solar power, which
is evacuated at the common DC bus of DFIG using a DC-DC boost converter in a cost effective way. The voltage and
frequency are controlled through an indirect vector control of the line side converter, which is incorporated with droop
characteristics. It alters the frequency set point based on the energy level of the battery, which slows down over
charging or discharging of the battery. The system is also able to work when wind power source is unavailable. Both
wind and solar energy blocks, have maximum power point tracking (MPPT) in their control algorithm. The system is
designed for complete automatic operation taking consideration of all the practical conditions. The system is also
provided with a provision of external power support for the battery charging without any additional requirement. A
simulation model of system is developed in MATLAB environment and simulation results are presented for various
conditions e.g. un availability of wind or solar energies, unbalanced and nonlinear loads, low state of charge of the
battery.