Open-Switch Fault Detection and Classification in Five-Level Neutral-Point-Clamped Inverter by Using Fuzzy Interface System

Abstract

In industry generally uses multilevel inverters (MLI) for high voltage and high power applications. As the number of switches increases in a multilevel inverter, the possibility of faults increases. A paramount concern for the power industry is the trustability of multilevel inverters. To increase the reliability of a switch, methods for detecting faults are necessary. This paper focuses on open switch fault detection and neutral point clamped (NPC) inverter classification. A fuzzy logic controller is used to diagnose faults, a logic-based approach. Based on the Discrete Fourier Transformation (DFT) output voltages and currents, fault detection and classification are carried out on faulty switches and clamping diodes. Clamping diodes are also susceptible to breakdown, although switches are more fragile. So it is crucial to develop a method for clamping diode fault diagnosis. Pulse width modulation (PWM) is also used to generate the gate pulse of insulated-gate bipolar transistors (IGBT) switches. Various simulations have been performed to validate the effectiveness of the proposed method.