Fully digital control of distributed photovoltaic power systems

This paper investigates power converter topologies and presents control techniques for a photovoltaic power system with parallel operation. Instantaneous power sharing control is used to achieve the current distribution and ensure a fast dynamic response, an adjustable load sharing capability and eliminate the circulation current. The system controller is based on a DSP to simplify the circuit and it is easy to modify the system. A modified method of tracking the photovoltaic maximum power points (MPPs) and forcing the system to operate close to these points is presented. Simulation and experimental results are presented to verify the proposed system performance.