COMPARATIVE STUDY OF DIFFERENT CONVERTER TOPOLOGIES FOR GRID CONNECTED PV SYSTEM

Abstract

Fossil fuel are depleting at very fast rate so we need to go for other renewable energy sources for the completion of energy demand. Solar energy is considered as one of the promising source of renewable energy. Due to heavy burden on environment because of the prolonged use of fossil fuels electricity generation through solar photovoltaic has emerged as an attractive option for reducing carbon emissions, remote area electrification and also reducing the electricity bills. Solar energy conversion equipments have longer life and need lesser maintenance and hence provide higher energy infrastructure security. Solar energy is available free of cost in whole world so it is the best option for getting electrical energy. This dissertation work presents work a comparative study of different converter topologies for grid connected PV system. Centralized inverter is used for large PV array system and it is less flexible. String inverter topology and Multi string inverter is used for small PV array and both are very flexible, while in string inverter one inverter is used for each parallel string and in multi string inverter only one inverter used for whole system with DC-DC converter in each parallel string. AC module inverter is the new and best technology because inverter is fitted in the PV modules directly so losses are very less. The MATLAB software has been used for modelling and simulation for different converter topologies for grid connected PV system. On basis of that model, different parameter like efficiency, current, voltage, and power has been calculated and compared. The performance parameters are also discussed with the mathematical expressions that can be used to analyse the performance of the PV system. Pulse width modulation inverter and 180 degree mode voltage source inverter is used for comparison of parameters. PWM inverter gave higher efficiency, less total harmonic distortion in voltage waveform compare to 180 degree mode voltage source inverter.