Browsing by Keyword "fault tolerance"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Fault-tolerant neutral-point-clamped converter solutions based on including a fourth resonant leg(2011-06) Ceballos, Salvador; Pou, Josep; Zaragoza, Jordi; Robles, Eider; Villate, José Luis; Martín, José Luis; POWER ELECTRONICS AND SYSTEM EQUIPMENT; RENOVABLES OFFSHORE; GENERALThis paper presents a new three-level topology based on the neutral-point (NP)-clamped converter. An additional leg is added to the basic topology. The main purpose of this leg is to provide the converter with fault-tolerant capabilities. In addition, during normal operation mode, the fourth leg can be used to balance the NP voltage. In this way, the low-frequency voltage oscillations that appear in the NP under some operating conditions are cancelled out effectively. As a result, the modulation strategy of the three main legs of the converter does not have to take care of the voltage balance and can focus on other aspects such as, for instance, minimizing the switching losses of the converter. However, the inclusion of the fourth leg produces some additional losses. A resonant topology is proposed to minimize the switching losses of this leg. Three different fault-tolerant solutions based on the fourth-leg topology are presented. A comparison of these topologies showing their respective advantages and drawbacks is made. Experimental results are presented to show the viability of this approach.Item Reliable Modular Multilevel Converter Fault Detection with Redundant Voltage Sensor(2017-01) Picas, Ricard; Zaragoza, Jordi; Pou, Josep; Ceballos, Salvador; POWER ELECTRONICS AND SYSTEM EQUIPMENTThis paper presents a fault-tolerant configuration for the modular multilevel converter (MMC). The procedure is able to detect faults in voltage sensors and semiconductor switching devices, and it can reconfigure the system so that it can keep on operating. Both switch and sensor faults can be detected by comparing the output voltage of a set of submodules (SMs), which is measured by a so-called supervisory sensor, with two calculated reference voltages. Faults in the supervisory sensors are also considered. Sensor faults are overcome by using a measuring technique based on estimates that are periodically updated with the voltage measurements of the supervisory sensors. Additional SMs are included in the arms so that the MMC can bypass a faulty SM and continue operating without affecting the output voltage of the phase-leg. Experimental results obtained from a low-power MMC prototype are presented in order to demonstrate the effectiveness of the proposed techniques.