Comparative Analysis of Three Non-Linear Control Strategies for Grid-Connected PV System

Abstract

This paper examines the limits of power injected to the grid for the photovoltaic (PV) system. Usually, the PV system injects to the grid active power with reactive power equal to zero. However, it can inject/absorb both powers according to the grid demand and maintain the stability of the grid characteristics (voltage and frequency). The proposed system consists of two main controllers: the DC/DC boost converter to track the possible maximum power from the PV panels and the grid-tied three-phase inverter. The controllers are designed based on a nonlinear adaptive backstepping approach, sliding mode control and the vector control strategy. The robustness of the proposed techniques is ensured by considering parametric uncertainties as well as external disturbances. In the proposed control strategies, the sliding mode control presents a small number of parameters than the other strategies. The reactive power is proposed by the grid manager which is controlled via the inverter. The simulation results indicate clearly the robustness of the sliding mode control in terms of injecting active and reactive power into the grid and improving power quality as compared to a backstepping controller and vector control.

KEYWORDS:

• Active and reactive power control
• Nonlinear control
• Photovoltaic system
• Three-phase grid

Acknowledgment

The authors would like to thank the anonymous reviewers and editors for their useful comments and suggestions.

Additional information

Notes on contributors

Amal Marrekchi

Amal Marrekchi received the engineering degree in electrical engineering from the National Engineering School of Sfax (ENIS), Tunisia, in 2012, and the “Summa Cum Laude” doctor degree in electrical engineering from National Engineering School of Sfax in 2017. She has a teaching position in electrical engineering and power electronics in the National Engineering School of Sfax since 2013. Her field of research is essentially based on electric drives modelling and simulation, control of power systems and renewable energy. Email: [email protected]

Salma Keskes

Salma Keskes received the engineering degree in electrical engineering from the National Engineering School of Sfax (ENIS), Tunisia in 2012, and obtained “Summa Cum Laude” doctor degree in electrical engineering from National Engineering School of Sfax in 2017. She has a teaching position in electrical engineering and power electronics in the National Engineering School of Sfax since 2013. Her research interests power system stability, transient stability, voltage regulation, linear and non-linear control theory including sliding mode control, backstepping control, adaptive control, robust control, flexible alternating current transmission system, SVC.

Souhir Sallem

Souhir Sallem received the PhD degree in electrical engineering from the National School of Engineering of Sfax, Tunisia, where she has a teaching position in electric systems since 2009. She received her University Habilitation in May 2017. Her research interests are mainly related to electric drives, modelling and simulation, control of power systems and renewable energy. Email: [email protected]

Mohamed Ben Ali Kammoun

Mohamed Ben Ali Kammoun received the PhD degree in electrical engineering from Paris VI (Jussieu) in 1976 and the doctorate degree in 1985 from the University of Tunisia. He has a teaching position in electrical engineering as a professor degree since 1992 in the National Engineering School of Sfax. His research interests are electrical machines: modelling, identification, stability and control; complex systems: reduction, decomposition, stability and control, application on machine and electrical network; and renewable energy. Email: [email protected]