Open-Circuit Fault Diagnosis and Fault-Tolerant Control for a Grid-Connected NPC Inverter

Abstract

This paper presents an open-circuit fault detection method for a grid-connected NeutralPoint Clamped (NPC) inverter system. Further, a fault-tolerant control method under an open-circuit fault in clamping diodes is proposed. Under the grid-connected condition, it is impossible to identify the location of a faulty switch by the conventional methods which usually use the distortion of outputs because the distortion of the outputs is the same in some fault cases. The proposed fault detection method identifies the location of the faulty switch and the faulty clamping diode of the NPC inverter without any additional hardware or complex calculations. In the case of the clamping diode faults, the NPC inverter can transfer full rated power with sinusoidal currents by the proposed fault-tolerant control. The feasibility of the proposed fault detection and fault-tolerant control methods for the gridconnected NPC inverter are verified by simulation and experimental results.

Impact of Postfault Flux Adaptation on Six-Phase Induction Motor Drives With Parallel Converters

“…Open-circuit faults are the most common and unpredictable ones in the converter [32,35] and they are also the most widely studied in literature [3]. A review of IGBT fault diagnostic and protection methods for power converters can be found in [36], while the detection and isolation to safeguard the integrity of the system is addressed in [37][38] for multiphase and multilevel converters, respectively. Other recent works have explored the fault-tolerant capability of multiphase drives against short-circuit faults in the converter [39] or machine [40], but it typically requires a specific design of the drive with a modular structure and dedicated winding arrangement [41].…”

A Principal Components Rearrangement Method for Feature Representation and Its Application to the Fault Diagnosis of CHMI

“…However, when its level increases, the reliability of the inverter will be reduced due to the eventual loss and faults of components [5,6]. The healthy functioning of an inverter plays an important role in the process of DC to AC power conversion [7]. Therefore, the fault diagnosis of CHMI is particularly important [8][9][10].…”

Real-Time Implementation of an Open-Circuit Dc-Bus Capacitor Fault Diagnosis Method for a Three-Level NPC Rectifier

“…Many diagnosis methods have been proposed in the recent literature to identify the open-circuit fault of power transistors and diodes utilized in the three-level NPC converter [5,6,7,8,9,10]. Some of the diagnosis and faulty components identification methods are based on the analysis of the instantaneous pole voltage and its duration [5], as well as the currents in the dc-bus neutral point.…”

“…The latters (pole voltages and current in the mid-point) are compared with their estimated values which are computed in terms of the switching states and dc-bus voltage or phase currents. Some other methods are based on the analysis of the average current Park's vector [7], the normalized average current [8], the phase current distortion [9], the slope method [10], etc.…”