SOME INVESTIGATIONS ON GRID CONNECTED PV SYSTEMS

Abstract

This thesis investigates the grid connected LCL interfaced solar PV system. The application of various control algorithms for controlling multifunctional voltage source converter used in the grid connected PV system are explored. The proposed schemes are designed and modeled on MATLAB platform. The first case deals with the design and analysis of LCL filter for interconnection with grid connected PV system. The proposed LCL filter based scheme improves stability of the system as well as more cheaper as compare to conventional LC filter. The LCL filter also reduce the harmonic components significantly and also shows better attenuation performance in the switching harmonics in the system as compare to conventional interfacing inductor based scheme. The second case presents the control algorithms for LCL filter interfaced grid connected power quality improved solar PV system. The scheme is suitable for grid connected solar PV system deals with nonlinear loads typically rectifier loads, battery charging loads laptops and uninterrupted power supplies etc. The scheme uses a three leg IGBT base voltage source converter with a capacitor on its DC link. This converter compensates harmonic and fundamental reactive power of the system. It ensures the grid has minimum harmonics while grid is feeding highly nonlinear loads. A conventional synchronous reference frame theory based control algorithm is successfully modeled and simulated to validate the proposed scheme. An improvement of the above scheme to obtain the adaptability and improved steady state performance is developed using Anti-Hebbian control algorithm based neural network scheme. This scheme has the learning ability which makes the system adaptable to the system parameter variations.