Control of single-stage grid-connected three-phase solar photovoltaic system using sliding mode control

In this paper, two approaches based on sliding mode control for controlling a single-stage grid-connected three-phase solar photovoltaic system have been presented. The sliding mode control is robust and has good disturbance rejection as compared to the conventional proportional-integral control. Another advantage is that feedback linearization is not required for controlling nonlinear systems. There are two controlled variables namely the dc-link voltage and the q-axis component of the line current of the Voltage Source Converter. In the first approach, twisting controller and first order sliding mode controller have been used. Super twisting controller has been used to control both the variables in the second approach. The propsed control scheme has been simulated to verify the results.

I. Introduction

In recent years, solar photovoltaic (PV) systems have attracted extensive research due to the adverse effects of the use of fossil fuels on the environment and global energy crisis. National policies have been adopted in favor of green energy. Moreover, in India, availability of high solar insolation, falling prices of solar PV panels and increasing cost of grid power have provided further encouragement to explore the possibilities of improving the performance of the solar PV systems.