An Improved Grid Tied Photovoltaic System

摘要

This paper suggests an alternate improved setup of connecting a photovoltaic generator (PVG) with the power grid. The proposed improved setup uses a single phase full wave controlled bridge rectifier working in an inverter mode of operation. The controlled bridge rectifier is operated in such a way that it should be able to extract maximum power from the PVG and inject it into the power grid at different solar irradiation levels. The performance of the proposed improved setup has been tested using MATLAB/SIMULINK toolboxes. The tests results showed a positive active power contribution of the PVG to the grid and maximum possible power values extracted from the PVG source were noted. Unfortunately, quite distorted current waveforms were encountered at the AC side of the bridge (i.e power grid side). To overcome such distortion, an active power filter has been shunted with the controlled bridge rectifier. The active power filter generated an out of phase current consisting of the sum of all undesired harmonic currents. In doing so, the power grid AC current ended up with nearly pure sinusoidal ac current waveforms. The duty of the active power filter has been further extended to reactive power compensation. In doing so. a quite reasonable power factor levels were reached in addition to the nice quality of the power grid current waveforms.