Investigation of the behavior of a three phase gridconnected photovoltaic system to control active and reactive power with DPC

Abstract This paper proposes an extended direct power control (DPC) for a three-phase PWM multilevel inverter fed by photovoltaic generation system (PVGS) and connected of a grid. The model contains a detailed representation of the main components of the system that are the solar array, and the grid side inverter multilevel inverter NPC VSI. In order to extract the maximum amount of from the photovoltaic generator, we propose an intelligent control method (fuzzy logic controller) for the maximum power point tracking (MPPT) of a PVGS. The DPC approach for multilevel inverter NPC which makes it possible to achieve unity power factor (UPF) operation by directly controlling its instantaneous active and reactive power. The other is a fuzzy logic controller, in the multi-DC-bus voltage control loop, developed to provide active power command. To achieve UPF operation, the reactive power command is set to zero. It is shown via simulation results that the proposed DPC has high performance. Moreover, the controller multi DC bus link voltages based on fuzzy logic has excellent performance in transient and steady states, a good robustness, a good dynamic behaviour response, and a good rejection of impact of load disturbance.