Grid connected PV system with maximum power point estimation based on reference cells

This paper proposes a control strategy for a single-stage, three-phase photovoltaic (PV) system connected to a distribution network. The control entails obtaining the maximum power point of the PV system by means of a control strategy that is based on an inner current-control loop and an outer DC-link voltage regulator. The current-control mechanism decouples the PV system dynamic from those of the network and searches for unitary power factor at the grid side. The DC-link voltage-control scheme achieves maximum active power output. The maximization of the output power is performed by operating the PV array at its maximum power point that is estimated by a proposed technique that uses two PV measuring cells, one operating in open-circuit and the other one in short-circuit.