Novel Control Strategy for Photovoltaic Systems in Three-Phase Grid-Connected Applications

MOLINA, MARCELO GUSTAVO; PONTORIERO, DOMINGO HECTOR; MERCADO, PEDRO ENRIQUE

Foz do Iguazú-Pr, Brasil

Congreso; XII Encuentro Regional Iberoamericano de CIGRÉ (ERIAC); 2007

CIGRÉ-Brasil

This paper proposes a novel control approach of a three-phase grid-connected photovoltaic system, incorporating a maximum power point tracker (MPPT) for dynamic active power generation jointly with reactive power compensation of distribution utility systems. A multi-level control scheme of the power converters is presented, including coordinated control of the power inverter and the dc-dc converter used as MPPT. The control technique proposed is based on the instantaneous active and reactive power theory on the synchronous-rotating d-q reference frame. The control algorithm for maximum power point tracking uses a “Perturbation and Observation” (P&O) method that proves to be efficient in tracking the MPP of the PV array for different environmental conditions. Validation of models and control algorithms is carried out through simulations by using SimPowerSystems of the Simulink/MATLAB™ environment. The results obtained demonstrate the good performance of the multilevel controller and models presented. The improved capabilities of the grid-connected PV system to rapidly exchange active power with the electric system, simultaneously and independently of the reactive power exchange, permit to greatly enhance the operation and control of the electric system.