Accurate Modeling and Control of Grid-Connected Photovoltaic System based on Average Equivalent Circuits

In this paper, a fully modeled grid connected photovoltaic system is presented using average modeling of power converters and analytic transfer function equations. The conduction and switching losses are also simulated and integrated into the model. A PQ control and voltage control of the decoupling dc-link capacitor are implemented, using the closed loop model to derive the gains for the controllers. The control parameters and output filter values are also accurately selected. Finally, the accuracy of the derived average models for DC/DC and DC/AC conversion stage is experimentally tested using a laboratory prototype.