Browsing by Keyword "Multilevel converter"
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Item Efficient modulation technique for a four-leg fault-tolerant neutral-point-clamped inverter(2008-03) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Martin, José L.; Robles, Eider; Gabiola, Igor; Ibáñez, Pedro; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHORE; SGThis paper presents a new low-loss modulation technique for the hybrid three-level four-leg converter. The total losses of the converter are reduced by about 18% on average compared to the standard three-leg neutral-point-clamped converter. Furthermore, the low-frequency voltage oscillation in the neutral point is completely cancelled, and the maximum benefit of the dc-link voltage is obtained. All these facts, together with the fault-tolerant ability due to the fourth leg, make this topology very interesting for applications such as wind generation, in which it is important to maximize efficiency and reliability. Some experimental results confirm the good performance of the proposed modulation technique.Item Efficient modulation technique for a four-leg fault-tolerant neutral-point-clamped inverter(2006) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Martin, Jose Luis; Robles, Eider; Gabiola, Igor; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHOREThis paper presents a new low-loss modulation technique for the hybrid three-level four-leg converter. The total losses of the converter are reduced on about 18% in average compared to the standard three-leg neutral-point-clamped converter. Furthermore, the low-frequency voltage oscillation in the neutral-point is completely cancelled, and maximum benefit of the dc-link voltage is obtained. All these facts, together with the fault-tolerant ability due to the fourth leg, make this topology very interesting for applications such as wind generation, in which it is important to maximize efficiency and reliability. Some experimental results confirm good performance of the proposed modulation technique.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 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 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.