Predictive Controller Design for a Grid-Connected PV Central Inverter

In this paper, a predictive control for power injection of a photovoltaic (PV) system to the grid is investigated. Structure of power conversion system is central and electrical power is injected into the grid by a single-phase inverter. Photovoltaic power generation control system usually consists of two loops: the outer loop for maximum power point tracking (MPPT) and the inner loop to control the output current. Since the time constant of the outer loop is much more in comparison with the inner loop, these two loops can be considered as decoupled loops. The aim of this paper is to inject a desired pure active power into the grid. This is done by controlling the output current. To achieve this goal, a predictive controller is proposed that controls the power by controlling the output current. Grid is modeled with a sinusoidal voltage source and is connected to the inverter output by an inductor. The proposed controller is quite simple for practical implementation and doesn’t require any modulator. Simulation results show good performance of the proposed controller.