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- Fault-tolerant SRM dive with a diagnosis method based on the entropy feature approachPublication . Fernao Pires, Vitor; Amaral, Tito; Cordeiro, Armando; Foito, Daniel; Pires, Armando J.; Martins, JoaoThe power electronic converter design is essential for the operation of the switched reluctance motor (SRM). Thus, a fault-tolerant power converter is fundamental to ensure high reliability and extend the drive operation. To achieve fault tolerance, fault detection and diagnosis methods are critical in order to identify, as soon as possible, the failure mode of the drive. To provide such capability, it is proposed in this paper a new fault-tolerant power converter scheme combined with a fault detection method regarding the most common power semiconductors failures in SRM drives. The fast and reliable proposed diagnosis method is based on the entropy theory. Based on this theory, normalized indexes (diagnostic variables) are created, which are independent from the load and speed of the motor. Through this method, it is possible to identify the faulty leg, as well as the type of power semiconductor fault. To test and evaluate the proposed solution several laboratory experiments were carried out using a 2 kW four-phase 8 / 6 SRM.
- A multilevel fault-tolerant power converter for a switched reluctance machine drivePublication . Fernao Pires, Vitor; Cordeiro, Armando; Foito, Daniel; Pires, A. J.; Martins, Joao; Chen, HaoReliability in the electrical drives is becoming an important issue in many applications. In this context, the reliability associated to the switched reluctance machine (SRM) is also an important area of research. One of the major problems, that strongly affect its operation, are drive power semiconductors faults. Typical power converter topologies used in SRM drives cannot handle faults in their power semiconductors. So, this paper presents a power converter topology that provides fault-tolerant capabilities to the drive under a switch fault. This power converter will be used considering that a change in the direction of the current that flows in the SRM windings does not affect the behavior of the machine. Besides that, the proposed power converter will allow to generate multilevel phase voltages in order to apply different voltage levels as function of the SRM speed. A laboratory power converter was developed to test the SRM drive in normal and faulty conditions. From the obtained results it was possible to verify the fault-tolerant capability of the drive under switch faults in different devices and failure modes. It was also possible to confirm the multilevel operation of the drive.
- A multilevel topology based on the T-Type converter for SRM drivesPublication . Fernao Pires, Vitor; Cordeiro, Armando; Pires, A. J.; Martins, João; Chen, HaoMultilevel power converters have been used in SRM drives to improve high speed operating characteristics and reduce switching frequency. Several topologies have been proposed to these drives but it requires an increased number of switches. In this paper it is presented a new multilevel topology for the SRM drives. This topology is based on the T-type structure and characterized by a reduced number of power semiconductors resulting in a low cost, size and weight system. With this topology it is possible to accelerate the magnetization and demagnetization process as well as the efficiency of the system through the reduction of the switching frequency at low speed operation. The characteristics and performance of the proposed topology will be verified through several numerical tests.