**3.1 First scenario**

In this scenario, a comparative study between the classical DTC and the proposed SVM-DTC-IOFL is done under a rated load torque (10 Nm), a variable speed profile

**Figure 3.** *XSG design flow.*

*Robust Control Based on Input-Output Feedback Linearization for Induction Motor Drive… DOI: http://dx.doi.org/10.5772/intechopen.104645*

and a reversal of the direction of rotation. In order to show the effectiveness of the suggested SVM-DTC-IOFL, it is compared with the classical DTC in terms of torque ripples and stator current distortion. The performance analysis is carried out with a sampling period equal to 100 μs.

The IM starts with a reference speed equal to 100 rad/sec. At t = 1 sec the reference speed decreases slowly to reach 100 rad/sec at t = 2 sec. At t = 0.5 sec, a rated torque is applied.

**Figure 5** presents the evolution of the rotor speed of the IM controlled by two control strategies. It can be noticed that the rotor speed converges to the reference speed for both control strategies. However, the proposed SVM-DTC-IOFL offers better performance in terms of ripples around the reference speed, as shown in **Figure 5(b)**. As given in **Figure 6(a)**, the suggested control strategy gives better performance in terms of ripples compared to the classical DTC (**Figure 6(b)**). **Figure 7** presents the three phase stator current consumed by the IM control by both control strategies. It can be seen that the proposed control strategy offers better performance in terms current distortions. In fact, for the suggested SVM-DTC-IOFL, the stator current has a smooth waveform (**Figure 7(a)**). **Figure 8** presents the evolution of the stator flux components for both control strategies. In can be seen that

**Figure 4.** *Full architecture of SVM-DTC-IOFL using XSG.*

**Figure 5.** *Speed response for: (a) proposed SVM-DTC-IOFL, (b) classical DTC.*

**Figure 6.**

*Torque response for: (a) proposed SVM-DTC-IOFL, (b) classical DTC.*

**Figure 7.**

*Three phase stator current for: (a) proposed SVM-DTC-IOFL, (b) classical DTC.*

### **Figure 8.**

*Three phase stator current for: (a) suggested SVM-DTC-IOFL, (b) classical DTC.*

the real stator flux converges to its reference value. In addition, the proposed control strategy gives better performance in terms of flux-ripple reduction. More details are illustrated in **Table 2**.
