An integrated active and reactive power control scheme for grid-connected photovoltaic production systems

The paper presents an advanced control scheme for a photovoltaic unit (PV) to suitably drive the injection of both active and reactive power into a MV radial distribution grid. Such algorithm allows a decoupled control of active and reactive power by properly adjusting the modulating signals of the PWM interface converter with the grid. A closed loop regulation scheme has been derived and guidelines for the design of the regulators are provided. The control algorithm has been applied to a real MV grid-connected PV power plant and several simulations have been performed in order to analyze the behavior of the system and to verify the effectiveness of the adopted regulation. The positive effect of reactive power support has been highlighted showing benefits on grid current and voltage profiles with respect to the typical case of the sole active power production.