A control structure for a photovoltaic supply system with power compensation characteristics suitable for smart grid topologies

A system controller for a three-phase grid-connected inverter for photovoltaic applications is presented. The active and reactive currents will both be controlled in order to realize active power supply and reactive power compensation. The three-phase inverter will be controlled by a fast and robust sliding mode controller. The active and reactive current references will be calculated in order to maximize the electrical energy produced by PV arrays and at the same time as a reactive power compensator. For the calculation of these references the maximum apparent power of the three-phase inverter is also considered. When the PV system is not working at full power the three-phase inverter can also be working as reactive power compensator. The grid injected reactive power is limited by the maximum apparent power of the inverter. This allows integrating this system into a smart-grid. Numerical simulations obtained in the Simulink environment are presented in order to validate the proposed system.