*4.1.4.3.3 Simulation results and discussion*

The two proposed schemes namely 1.Fuzzy Logic Controller (FLC) for DTC-SVM and 2.Artificial Neural Network (ANN) controller for DTC-SVM respectively for IM. Has been simulated using MATLAB version R2009a and the results are compared and shown in **Table 4**. Both of the proposed scheme methods uses HASVPWM. The parameters of IM used in the simulation are given in the appendix.

The torque ripple can be calculated by using the relation.

Torque Ripple Factor ¼ ð Þ Peak to Peak torque *=*Rated torque (16)

The simulation results of FLC for DTC-SVM of IM with HASVPWM is shown in **Figures 18** and **19**.The simulation results of ANN for DTC-SVM of IM with HASVPWM is shown in **Figures 20** and **21**.

From **Figure 19** (Torque ripple waveform) it is inferred that the torque ripples oscillates from 9.5 Nm (Minimum) to 10.1 Nm (maximum) for the given Reference torque of 10 Nm.

Torque Ripple factor (%) as per Eq. 23 is given by = ((10.01–9.5)/10) � 100 = 0.51/10�100 = **5.1.**

**Figure 19.** *Torque ripples for FLC based DTC-SVM of IM with HASVPWM.*

It is clear that variation in Torque ripples shown in **Table 4** is less in case of ANN and they can achieve a minimum torque ripple than other control techniques. It has been viewed that the discussed control strategy has helped in reducing the torque ripples. Thus, by using FLC and ANN based controller for DTC of IM, the ripples

*Torque ripple comparison of FLC and ANN based DTC- SVM of IM with HASVPWM.*

*Torque Ripple Reduction in DTC Induction Motor Drive*

*DOI: http://dx.doi.org/10.5772/intechopen.94225*

The limits of the torque hysteresis band are controlled by FLC. It entails a minimization of the torque ripples as well as an improvement of the dynamic performances of IM. The FLC selects the optimum bandwidth of the torque

angle are the input to FLC. The switching state of the inverter is a crisp value

A detailed classification and comparison of DTC strategies like SMC, FLC and ANN in terms of performance parameters of induction machine were discussed

The fuzzified parameters such as torque error, stator flux errors, and stator flux

The PI controller and FLC algorithm have been implemented for the three-phase induction motor and it is found that the proposed FLC scheme is better than the

The effective DTC improvements are achieved by Fuzzy logic controller thereby the ripples in torque and flux are reduced, consequently secondary problems for the motor such as heating, mechanical vibration, aging are also rectified. The merits of

A multilayer ANN allows to replace both hysteresis comparators and the

The ANN offers the following merit over classical DTC.

i. The complexity of the controller is reduced;

are reduced completely.

**Figure 22.**

**5. Modern strategies of DTC**

**5.1 Fuzzy logic control (FLC)**

hysteresis in real time [9].

in [20].

**155**

obtained as an output from the FLC [11].

the conventional are also preserved [22].

**5.2 Artificial neural network (ANN)**

selection table in classical DTC.

conventional DTC control with PI control in [21].

**Figure 20.** *Speed and torque output for ANN based DTC-SVM of IM with HASVPWM.*

**Figure 21.**

*Torque ripples for ANN based DTC-SVM of IM with HASVPWM.*

From **Figure 21** (Torque ripple waveform) it is inferred that the torque ripples oscillates from 9.55 Nm (Minimum) to 10 Nm (maximum) for the given Reference torque of 10 Nm.

Torque Ripple factor (%) as per Eq. 23 is given by = ((10–9.55)/10) � 100 = 0.45/10�100 = **4.5.**

**Figure 22** shows the comparison of Torque Ripple of FLC and ANN based DTC-SVM of IM with HASVPWM at 1000 rpm.

*Torque Ripple Reduction in DTC Induction Motor Drive DOI: http://dx.doi.org/10.5772/intechopen.94225*

**Figure 22.** *Torque ripple comparison of FLC and ANN based DTC- SVM of IM with HASVPWM.*

It is clear that variation in Torque ripples shown in **Table 4** is less in case of ANN and they can achieve a minimum torque ripple than other control techniques. It has been viewed that the discussed control strategy has helped in reducing the torque ripples. Thus, by using FLC and ANN based controller for DTC of IM, the ripples are reduced completely.
