Fault diagnosis in grid‐connected PV NPC inverters by a model‐based and data processing combined approach

Abstract

This study presents a fault detection and isolation (FDI) method for open-circuit faults (OCFs) in the switching devices of a grid-connected neutral-point-clamped (NPC) inverter for photovoltaic (PV) applications. The proposed methodology addresses the fault diagnosis problem by a combined model-based and data processing perspective to study single and simultaneous faults in the NPC inverter. For the model-based scheme, a bank of sliding-mode proportional-integral observers is suggested to estimate the fault profiles under an additive model. Thus, from the estimated fault profiles, and by performing a directional residual evaluation in a fixed reference frame, single and simultaneous fault scenarios can be isolated in the NPC inverter. However, for some fault classes, there is some ambiguity by just the model-based approach that is overcome by employing the average line currents to construct extra fault signatures. The proposed FDI scheme only requires the measurements of line currents and grid voltages in the diagnosis media and can isolate 6 × 2 single OCFs and 12 × 4 simultaneous OCFs in the order or lower than a fundamental period of the grid frequency. Our new FDI methodology is validated through experimental data from a practical PV system in a closed-loop grid-connected NPC inverter under single and simultaneous OCF conditions.

Diagnosis of Multiple Open-Circuit Faults in Three phase Induction Machine Drive Systems Based on Bidirectional Long Short-Term Memory Algorithm

“…More recently, intelligence artificial tools had become more attractive for fault diagnosis and fault classification issues [31][32][33][34][35][36][37][38][39][40][41][42][43]. Indeed, data driven approaches are only based on recorded data obtained from measured quantities instead of specific complex mathematical models.…”

Industrial Fault Detection Based on Discriminant Enhanced Stacking Auto-Encoder Model

“…The improvement of science and continuous growth of the economy causes increasing scale of the process industry and closed coupling degree so that the abnormalities and faults of any equipment in system such as power system and industrial equipment will affect the system's normal operation [1][2][3]. Therefore, fault detection should run during the whole processing industry, it is an indispensable part of process monitoring and plays a vital role to ensure safety and stable operation of the whole process industrial system.…”

Open‐switch fault diagnosis in three‐level rectifiers based on selective calculation method for instant voltage deviation

“…The FDI methods for NPC converters can also be divided into current‐based methods [20–22], voltage‐based methods [23, 24] and model‐based methods [25–28]. In [21], a current‐based method was proposed for NPC inverters of ac motor drives.…”

“…And the residual between the measured current and the estimated one was used to detect open‐circuit faults in [25]. A model‐based algorithm was proposed by building a sliding‐mode proportional‐integral observer to estimate the fault profiles with data processing of the line currents and grid voltages [26].…”