Advanced Nonlinear Control of Single-Phase Grid Connected PV Generator

Abstract

In this article, we address the problem of the controlling PV generators connected to the single-phase grid is addressed. The PV system presented consists of a PV generator, a DC_AC inverter, an LCL filter and a single-phase grid. The main advantages of the studied system are: the abundance of the use of a DC_DC converter, the minimization of the total harmonic distortion of the current injected into the grid, the stabilization of the system, the great reliability and high efficiency. In this paper, we seek to achieve the following objectives: (i) extracting the maximum power from the PV generator, (ii) setting the DC-link voltage to its reference voltage vp,ref, (iii) injecting a sinusoidal and in phase current with the grid voltage (unit power factor UPF), while ensuring a total harmonic distortion (THD) less than 5%. To fulfill the above objectives, a nonlinear controller based on a nonlinear state model is proposed. This controller is realized by the Integral Backstepping technique. The results of the simulation showed that the extraction of the maximum power and the injection of the current with the unit power factor (UPF) are obtained whatever the climatic conditions.