## 1 Introduction  
There has been a renewed interest in the last decades concerning Switched Reluctance Motor (_SRM_) drives for a wide range of applications. One of the applications in which several studies were made about the type of motor that is more adequate to be used, is related to the electric vehicles (_EV_). From these studies, it was possible to see that the _SRM_ is a very interesting option for this kind of application [1; 2; 3; 4]. Another application that was verified that this machine is indicated to be used due to their simplicity and robust design, is related to their use as generator, namely, to extract energy from the wind and ocean waves [5; 6; 7; 8; 9; 10]. This machine is also very indicated to be used in applications associated with water pumps [11; 12]. There are also other applications in which this machine can also be used as can be seen in the work [13]. In fact, in most safety-critical applications a continuous drive operation (in normal or degraded mode) must be assured in the presence of a drive failure until a possible stop to repair. The interest in this motor is due to some important characteristics, such as high reliability level, high efficiency, simplicity of operation, and robust structure [13]. In contrast to other motors, the \(SRM\) has magnetic independence of the motor phases and withstands certain failure modes in motor windings or in the inverter circuitry without excessive degradation of its operation. Electrical drives play, in general, a very important role in many industries and applications, being essential to detect and diagnose failures in a very early stage in order to avoid risk to human life, damage of the environment or high costs arising from downtime, among other problems. Using suitable detection and diagnosis methods it becomes possible to replace faulty devices or parts by on-line or standby redundant devices and/or apply fault-tolerant control strategies. One of the characteristics of the \(SRM\) is that it requires a power electronic converter [9; 10; 11; 12; 13; 14; 15; 16; 17; 18]. Although the \(SRM\) presents a very high reliability level, the same does not happen with the power converter [19]. Normally the main problems of power converters are the failures in the power semiconductor devices. There are two possible failure modes associated with these components: open and short-circuit failures. In the case of an open-circuit failure, there will be a break in the excitation of the motor winding that is connected to such device. This can seriously affect the speed and torque of the motor. On the other hand, under short-circuit failure mode, the current through the motor winding connected to the power device under fault will increase to values that can irremediably damage that winding if proper precautions are not taken. To mitigate such problems, a fast-reliable detection and diagnosis of the power device under failure is normally necessary to minimize abnormal functioning and to avoid possible damages in the motor. To overcome these problems a fault-tolerant power converter is required. Thus, several research papers have been addressed to this topic. In [20; 21] it is proposed an asymmetric three-level neutral point diode clamped converter for the \(SRM\) drive. However, this scheme does not handle with all types of failure modes. In [22] another scheme is presented that also has fault-tolerant capability. In this scheme it is only required additional connections between the converter legs. However, it does not provide fault tolerance to short-circuit failures in the power devices. Other fault-tolerant topologies are presented in [23; 24; 25]. However, they require extra transistors and/or an \(SRM\) with extra connection windings per phase. As mentioned before, one of the most important aspects related to fault-tolerant converters is the requirement of reliable fault detection and diagnosis methods [26; 27; 28; 29]. The identification of a power device failure requires the use of advanced algorithms.