INVESTIGATIONS ON POWER CONVERTER TOPOLOGIES FOR RENEWABLE ENERGY APPLICATIONS

Abstract

Renewable energy sources are gaining popularity due to shortcomings of conventional sources of energy. Solar power is considered a very promising source for electric power generation. The abundance of sunlight over a large area of the earth surface gives rise to several applications of photovoltaic systems. These systems are widely used today to provide power to either standalone loads or for connection to the power system grid. Integration of PV generators with power system grid is presented in this work. There has been a phenomenal development in the area of power converter topologies for PV systems. Two level and three level voltage source inverters are amongst the most popular topologies for grid connected systems. Investigation of load and insolation based variations are studied for these two topologies. Maximum power point tracking (MPPT) is a very important consideration that is taken into account when building a new photovoltaic power system. This is needed in order to extract maximum power output from a PV array under varying atmospheric conditions to maximize the return on initial investments. In dual stage PV system boost DC-DC converter is responsible for this particular function. There is also a need for developing control techniques for three phase grid connected PV systems including a method for DC link voltage control that can stabilize the voltage at the inverter input. Control of injected current is also essential for unity power factor operation. Simulation of the designed PV system has been carried out in MATLAB and effects of change in conditions have been investigated for two topologies in consideration.