Fault-Diagnosis and Virtual Flux-Based Tolerant Control for Grid Connected PV System

Abstract

This article presents easy and robust Measurement Fault Detection and Isolation (MFDI) and Fault Tolerant Control (FTC) technique against grid voltage measurement failure, where scaling and dc-offset errors are considered. The proposed MFDI method is based on grid voltages orientation, which enables to generate two residuals. It does not require an extra hardware and is insensitive to system parameters variation; therefore, the model knowledge is not necessary. FTC technique is applied to overcome the fault. It is focused on Virtual Flux using Second-Order Generalized Integrator with a Frequency Locked-Loop. The estimated quantity is injected into the system control instead of the erroneous measurement. Simulation results prove the effectiveness of the proposed MFDI and FTC methods against different magnitude and type of grid sensor faults, and well identify the occurrence fault in each phase. In addition, it is characterized by a lower software capacity compared with model-based methods. An experimental platform was used to validate the obtained results and to show the reliability of the proposed techniques.

Keywords:

• PV system
• fault detection
• fault isolation
• SOGI-FLL
• virtual flux
• grid voltage
• estimation
• fault tolerant control

Additional information

Funding

This work was supported by the Tunisian Ministry of High Education and Scientific Research under Grant: Research Laboratory of Processes, Energetics Environment and Electrical Systems LR34ES18, Gabes University, Tunisia.

Notes on contributors

Fatma Ben Youssef

Fatma Ben Youssef was born on November 16, 1990, She received in Gabes-Tunisia. She received the B.S. degree in automatic-electrical engineering from the National Engineering School of Gabes, University of Gabes, in 2014, and the Ph.D. degree from the National Engineering School of Gabes, in 2018. She is currently a contractual assistant at the Higher Institute of Industrial Systems. Her research interests include power electronics, converters control, fault detection, fault tolerant control, and renewable.

Ahlem Ben Youssef

Ahlem Ben Youssef was born in Tunisia, in 1984. She received the Ph.D. degree in electrical engineering from the National Engineering School of Tunis (ENIT), Tunis, Tunisia, in 2014. She is currently an Assistant Professor at the Higher Institute of Industrial Systems of Gabes, University of Gabes, Tunisia. Her research interests are in the detection and isolation method based on Luenberger observer and fault tolerant control of railway electrical traction.

Lassaad Sbita

Lassaad Sbita was born in Hammam Lif, Tunisia, in 1962. He received the B.E. degree in electrical engineering from the University of Tunis, Tunisia, in 1985, and the D.E.A. and Thesis degrees in electrical engineering from the ENSET of Tunis, Tunisia, in 1987 and 1997, respectively. In 1988, he joined the Department of Electrical Engineering, ENIS, University of Sfax, as a Professor Assistant, and in 1991 with the Department of Electrical Engineering, ENIG, University of Gabes, became an Associate Professor in 1998 and a Professor in 2009. Dr. Sbita is a director of a research unit of PV, wind and geothermal systems, which ministry code is “ur11es82.” He was the General Chair of the IEEE International Conference on Green Energy Conversion Systems (GECS 2017). His current research interests include power electronics, electrical machines and drives, active filters, renewables energies, electrical grid, and power quality.