Browsing by Keyword "Fault tolerance"
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Item Fault-tolerant multilevel converter topology(2006) Ceballos, Salvador; Pou, Josep; Gabiola, Igor; Villate, José Luis; Zaragoza, Jordi; Boroyevich, Dushan; POWER ELECTRONICS AND SYSTEM EQUIPMENT; GENERALThis paper presents a modified topology of the neutral-point-clamped converter. The main change consists on adding a fourth leg, which is based on the flying-capacitor converter structure. The aim of this additional leg is to provide fault tolerance to the converter. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage oscillations that appear in the neutral point of the standard three-level topology for some operation conditions no longer exist. As a result, the modulation strategy of the three main legs of the converter does not have to take care of voltage balance, and it can be design to achieve optimal output voltage waveforms, as well as to improve efficiency of the converter. Some simulation results are presented to show viability of this approach under both, normal operation mode and fault event. Experimental results are expected to include in the final paper.Item Performance evaluation of fault-tolerant neutral-point-clamped converters(2010-08) Ceballos, Salvador; Pou, Josep; Robles, Eider; Zaragoza, Jordi; Martin, Jos Lus; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHOREThis paper presents a study of the fault tolerance capacity of a neutral-point-clamped converter. Different faults in power semiconductors are considered, and the available postfault states of the converter are shown. In regard of the operation limits, two possible solutions are presented. In these solutions, adding a reduced number of additional components, the behavior of the converter when a switch fails improves considerably. Furthermore, an analysis of the neutral-point voltage balancing conditions after a fault and reconfiguration of the system is also evaluated. Experimental results that prove the correct operation of the proposed topologies are shown.Item Soft-switching topology for a fault-tolerant neutral-point-clamped converter(2007) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Robles, Eider; Villate, José Luis; Martín, José Luis; POWER ELECTRONICS AND SYSTEM EQUIPMENT; GENERALThis paper presents a new three-level topology based on the neutral-point-clamped converter. The new topology includes a fourth leg that provides fault tolerance to the converter. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage oscillations that appear in the neutral point of the standard three-level topology for some operation conditions no longer exist. As a result, the modulation strategy of the three main legs of the converter does not have to take care of voltage balance, and it can be design to improve the efficiency of the converter. On the other hand, the addition of a fourth leg to the converter produces additional losses. However, in order to eliminate switching losses of this leg, all the power devices commutate under zero-current or zero-voltage transitions. Some simulation results are presented to show viability of this approach under both, normal operation mode and fault event.Item Survey on fault operation on multilevel inverters(2010-07) Lezana, Pablo; Pou, Josep; Meynard, Thierry A.; Rodriguez, Jose; Ceballos, Salvador; Richardeau, Frédéric; POWER ELECTRONICS AND SYSTEM EQUIPMENTThis paper is related to faults that can appear in multilevel (ML) inverters, which have a high number of components. This is a subject of increasing importance in high-power inverters. First, methods to identify a fault are classified and briefly described for each topology. In addition, a number of strategies and hardware modifications that allow for operation in faulty conditions are also presented. As a result of the analyzed works, it can be concluded that ML inverters can significantly increase their availability and are able to operate even with some faulty components.Item Three-leg fault-tolerant neutral-point-clamped converter(2007) Ceballos, Salvador; Pou, Josep; Robles, Eider; Zaragoza, Jordi; Martín, José Luis; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHOREThis paper presents a study of the fault tolerance capacity of a neutral-point-clamped (NPC) converter. Furthermore, two possible solutions are presented. In these solutions, adding a reduced number of additional components, the behavior of the converter when a switch fails improves considerably. Simulations results that prove the correct operation of the proposed topologies are shown.Item Three-level converter topologies with switch breakdown fault-tolerance capability(2008-03) Ceballos, Salvador; Pou, Joseph; Robles, Eider; Gabiola, Igor; Zaragoza, Jordi; Villate, José L.; Boroyevich, Dushan; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHORE; GENERALThis paper presents some modified topologies of the neutral-point-clamped converter. In all of them, the main change consists of adding a fourth leg, which is based on the flying-capacitor converter structure. The aim of this additional leg is to provide the converter with fault tolerance. Furthermore, during normal operation mode, this leg is able to provide a stiff neutral voltage. Consequently, the low-frequency voltage oscillations that appear at the neutral point of the standard three-level topology in some operating conditions no longer exist. As a result, the modulation strategy of the three main legs of the converter does not have to take care of voltage balance, and it can be designed to either achieve optimal output voltage spectra or improve the efficiency of the converter. Simulation and experimental results are presented to show the viability of this approach both under normal operation mode and in the event of faults.