Efficiency Investigation of a Grid Connected PV System with Power Smoothing

Efficiency is of paramount importance in renewable energy technologies as the energy loss is converted into financial loss to the investor. A thorough investigation of efficiency is attempted in a grid connected photovoltaic (PV) system employing smoothing. Smoothing is necessary due to cloud movements and other reasons where the produced power is fluctuating. Partial controlled storage in a small lithium battery is applied to alleviate the problem of stability and voltage flickering of the grid. Losses in such systems are identified in the switching transistors, diodes and inductors. The grid connected system consists of the PV modules, the MPPT and the inverter. A bidirectional DC-DC converter and a lithium battery are used for smoothing. For the purpose of this research, PSIM is employed as it contains all the elements for simulating a grid connected PV system. Furthermore, it simulates transistors, diodes and inductors with their characteristics derived from the datasheets.