MODEL PREDICTIVE CURRENT CONTROL OFGRIDCONNECTED THREE-PHASE INVERTER FOR PV SYSTEMS

Abstract

This paper presents model predictive current control of a grid-connected two-level
voltage-source three-phase inverter for a photovoltaic(PV) system. The output of a solar
array is fed to a DC-DC boost converter to make a DC link voltage that is fed to theinverter.
In this PVsystem, the theory of model predictive control (MPC) is applied to design an
effective controller for the grid-connected currents. In addition, asuitable PI controller is
used to compute the reference grid-connected currents and keep a DC link voltagefor the
inverter to be constant. Model of the system is established to predict the controlled
variables. Optimal switching states are selected by minimizing a cost function defined
using the difference between the reference and measured grid-connected currents for each
sampling period. Simulation results obtained using MATLAB/Simulink show that if the
reference currents change dynamically, the model predictive controller has the ability of
fast current regulation. Moreover, thiscontroller can also result in an effectively injectionof
the active power into the grid.