An open-switch fault detection method and tolerance controls based on MPDPC in a NPC rectifier

Abstract

In recent years, fault tolerance has become one of the most interesting topics because the open-switch faults rise to unbalance of the AC input currents and unable to control DClink voltage that can cause serious damage to the connected application. This paper proposes a model predictive direct power control (MPDPC) method to tolerance control using a neutralpoint clamped (NPC) topology in a switch fault situation. This method uses the cost function concerning active power and reactive power to select a voltage vector and can detect the openswitch fault without using additional devices or complex calculations. Simulations are carried out to confirm the reliability of the proposed fault-detection method.

A comprehensive review of fault diagnosis and fault-tolerant control techniques for modular multi-level converters

“…It has shown much attention in the industry, and it has given a suitable solution in high power transmission applications. 6 The MMC consists of a series of sub-modules (SMs), including many switch modules, called the half-bridge and full-bridge modules. Due to the usage of many switches, switch faults have occurred in MMC, which is one of the main reasons for the system's failure.…”

Fault Analysis and Non-Redundant Fault Tolerance in 3-Level Double Conversion UPS Systems Using Finite-Control-Set Model Predictive Control

“…On the other hand, a complete correction of the fault is not always possible. This type of approach can be based solely on software adaptations, relying only on changes to the control and modulation strategies [21][22][23][24][25][26][27][28][29][30], or require some changes to the converter topology . Software-based fault correction presents the lowest possible complexity and cost but typically carries significant operational limitations, resulting in reduced post-fault performance.…”

“…In NPC converters, the inherent voltage vector redundancy allows a greater degree of control when in the presence of a fault, in comparison to 2-level converters. Hence, several solutions have been proposed to alter the control and modulation stages to correct IGBT faults in PWM-based AC/DC converters [22][23][24][25][26][27]29]. In AC/DC applications, the IGBTs have a reduced use compared to the diodes, which allows these techniques to acceptably correct outer IGBT faults [22,23].…”

“…In both cases, the post-fault control-set is merely a subset of the one available in normal conditions instead of a distinct one, making controller implementation significantly simpler. The solutions in [27,31] provide fault-tolerant capabilities to 3-level NPC rectifiers and motor drive inverters and also consider a subset of the initial control set for fault-tolerant operation. In these cases, switching states affected by the fault are excluded from the control set only when current in the faulty phase flows in a specific direction (affected by the fault), which allows the converter to still use them in other conditions.…”

“…However, these studies do not explain how this exclusion is implemented. Moreover, [27] considers only faults in inner IGBTs of the NPC converter (all other faults are overlooked) and, since no other corrective actions are taken, the converter is actually unable to correct the effect of these faults (it is somewhat reduced, but high current distortion still exists). In [31] both inner and outer IGBT faults can be corrected.…”