Modeling and experimental validation of a DSP controlled photovoltaic power system with battery energy storage

For photovoltaic (PV) energy system integration to the power grid, knowledge of its operating characteristics is invaluable to power engineers. Such knowledge can effectively be achieved via system modeling, simulation and experimental studies. This paper develops models for an integrated PV power system which comprises PV array, SEPIC (single ended primary inductance converter) converter, bidirectional dc-dc converter, dc-ac converter, and battery energy storage using Matlab/Simulink. The models are used for simulation studies to investigate: 1) the response of the system to the ever-changing environmental variables, 2) the ability to track the maximum power point, 3) the role of the battery energy storage in the mitigation of voltage and power oscillations, and 4) the role of the inverter in ensuring compliance to the grid requirements. To validate the simulation results, the converters and sensor boards are built and a DSP (digital signal processor) controller is used to implement the control functions.