A fault-tolerant T-type three-level inverter system

Investigation of Fault-Tolerant Capabilities in an Advanced Three-Level Active T-Type Converter

“…After the introduction of three-level T-Type and I-Type neutral point clamp (NPC) converters in 1981 [1], different fault-tolerant solutions and circuit topologies have been introduced in the literature to improve the reliability of the three-level converters [2]- [3] [11]. The fault-tolerant capability of the conventional T-Type inverter has been investigated in [2].…”

“…In certain safety-critical applications, such as the aforementioned MEA, EV, and UPS, where the rated output power is crucial, the derated output voltage and power may not be allowable. Two other faulttolerant T-Type inverter topologies with redundant phase legs were reported in [3] and [4] and can tolerate any open-circuit and short-circuit switching faults. However, the redundant leg is not leveraged in normal operation and is just reserved for the faulty condition.…”

A fault-tolerant topology of T-Type NPC inverter with increased thermal overload capability

“…where rated voltage is a stringent requirement. One more existing solution for the fault-tolerant operation of T-Type NPC inverters is mainly achieved by paralleling one or three redundant inverter legs, as reported in [5] , which does ensure a **Standard Drives Business Rockwell Automation Mequon, Wisconsin, 53092…”

“…As a matter of fact, most of the redundant semiconductor devices in the existing fault-tolerant topology idle, under healthy conditions, in the circuit without contribution to system performance, while conversely degrading system efficiency due to additional switching and conduction losses [5]. Therefore, it would be of great significance to improve the inverter topology to obtain certain fault-tolerant characteristics, while guaranteeing rated output voltages under faulty conditions and with acceptable efficiency degradation under healthy condition.…”

A fault-tolerant T-Type multilevel inverter topology with soft-switching capability based on Si and SiC hybrid phase legs

“…Therefore, it would be of great significance to improve the inverter topology with improved fault-tolerant characteristics, to guarantee full output voltages under post-fault conditions. The existing solutions for the faulttolerant operation of T-Type inverters are mainly achieved by paralleling multiple redundant inverter legs, such as the topology detailed in [4] , which achieves full output voltage under inverter fault-tolerant condition, but at a much higher system cost with decreased inverter efficiency due to a large number of redundant semiconductor devices involved in the circuit. As a matter of fact, most of the redundant semiconductor devices in the existing fault-tolerant topology simply idle in the circuit without contribution to system performance improvement under healthy conditions, which in turn decrease the inverter efficiency due to the associated device losses.…”