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.