A Review of Open-Circuit Switch Fault Diagnostic Methods for Neutral Point Clamped Inverter

Abstract

Due to numerous advantages, a neutral point clamped (NPC) inverter is a preferred choice for high-power applications and renewable technology. The reliability of the NPC inverter is a major concerning factor during the assessment of system performance as power semiconductor switches are vulnerable to abnormal conditions. Open-circuit (OC) switch faults are not as dangerous as short circuit (SC) faults but eventually have enough potential to cause cascaded failure to other components in the system and thus need to be supervised carefully. The OC faults result in a distortion of voltage and current signals in the NPC converter. Based on these signals, over the past few years, many efforts have been made to identify and localize the OC switch fault to the switch level in the NPC topology. In this paper, a review of different OC switch fault diagnostic methods is provided. Starting from the NPC inverter operation under healthy and faulty conditions, the various possible and unavailable switching states along with the deviation in pole voltage under different switch fault conditions is discussed. Then, based on the approach used for system-based fault detection, the OC fault detection methods are classified. The various OC methods are further discussed on the basis of signal, i.e., current, voltage or a combination of both signals used as a signature for fault detection. Emphasis is given to the principle involved, diagnostic variables utilized, the implementation approach and the diagnostic time required. Finally, the approaches are tabulated so as to provide a quick reference for NPC fault diagnostics.

Currents Analysis of a Brushless Motor with Inverter Faults—Part II: Diagnostic Method for Open-Circuit Fault Isolation

“…Figure 6a displays the impact of different torque values on rMSBubbEn with two open-circuits on T a and B a . rMSBubbEn decreases for load in the range (1,2), increases in the range (2, 3) and is followed by a decrease in the range (3,5). This case is similar to the previous one: the distance between the rMSBubbEn of healthy phases (b and c) and the rMSBubbEn of open-circuit phase a is nearly constant.…”

“…In recent years, numerous open-switch fault diagnostic methods applied in multilevel inverters have been presented [1][2][3]. Fault detection and isolation methods for Mosfet or IGBT open-circuit faults have been studied in previous works, particularly focusing on arm voltages or current measurements.…”

A Comprehensive Review of Supervised Learning Algorithms for the Diagnosis of Photovoltaic Systems, Proposing a New Approach Using an Ensemble Learning Algorithm

“…The IGBT (insulated gate bipolar transistor) power switch, being the main energy transfer component, is the most likely source of failure in the photovoltaic inverter [69]. The most common faults that can occur during the inverter's operation are open-circuit, insulation faults and short-circuit faults [70].…”

A Review of Symmetry-Based Open-Circuit Fault Diagnostic Methods for Power Converters

“…SC faults are often accompanied by overcurrent, which will trigger a circuit breaker, fuse, or other hardware-protection circuits immediately and are easy to detect. Whereas an OC fault will generally not cause the system to shutdown immediately, but degrade the system's performance, such as by creating voltage unbalance, harmonic distortions, and system fluctuations [4,5]. Even worse, if not dealt with in a timely manner, such OC faults may lead to cascading failures or even system crashes, causing a loss of life and property [6].…”

“…At present, some scholars have summarized and analyzed the methods use for diagnosing faults in power converters, which has promoted the development of research on diagnosing the faults in power converters [4,16,24]. In [4], a detailed analysis of the current path in NPC inverters under healthy and different fault conditions was conducted, and the performance of three types of diagnostic methods was summarized in depth. However, there is currently no literature that systematically summarizes the symmetry-based fault diagnosis methods.…”