## 6 Results Discussion  
The validation of the proposed SMO observer, which is used by the IRFOC control system shown in Figure 1, has been accomplished by using three tools: the first is through using the Hardware in the loop RT simulator shown in Figure 2, the second simulation test is carried out using the Matlab/Simulink environment, and finally the third test which is performed experimentally using TMS320C32 DSP based control board. The parameters of the used five-phase IM used in the three tests are given in Table 2, and the parameters of the proposed SMO observer are given in Table 3.  
For the first test shown in Figure 3, the performance of the observer is investigated at operating speed of 1000 RPM, with a sudden change in the estimated rotor resistance. This is to investigate the sensitivity of the proposed adaptive SMO observer. It is found that a sudden variation in the resistance value has a null impact on the estimated flux signal, the slight deviation demolishes and the estimated signal matches again the reference in a very short period (almost 0.2 s). At last, the observer's dynamic is tested when changing the motor load at time t = 25s. The obtained results in Figure 3 report that the behavior of the drive is normal i.e. smooth stator currents are obtained while maintain their ratings, both rotor speed and rotor flux track effectively their reference values with minimum error and high matching precision. The obtained results in this test also confirm the high dynamic performance of the controller when changing the load torque from 0 to 70% of its rated value.  
In the second test, which is carried out using the Matlab/Simulink software, the dynamic behavior of the proposed SMO observer is tested through investigating the estimated values of rotor flux, which under parameter variation, plays an important role in estimating the rotor speed. The test is performed when changing the rotor resistance value to 1.5 \(\star R_{m}\) at time t = 0.5 s while observing the rotor flux with and without using the SMO observer. The obtained results in Figure 4 approved the vital role that the SMO observer plays in maintaining the estimated flux values within the reference limits.  
Figure 6: Dynamic performance of five-phase IM drive at low speed operation.  
The third test is carried out experimentally using the TMS320C32 DSP based control board. In this test the dynamic performance of the SMO observer is tested for different operating speeds (medium and low). In Figure 5, the drive is operated at 250 RPM, with two values of load torque: 0 and 50% of rated load torque. The obtained results illustrate the feasibility of the proposed sensorless controller via obtaining sinusoidal signals of rotor flux and stator currents, while tracking precisely the reference speed and following the torque change as well.  
The drive performance is also tested experimentally at very low speed operation (20 RPM), which is considered as a challenge to the SMO observer. The results shown in Figure 6 confirm and validate the effectiveness of the proposed SMO in achieving the control targets and estimating the rotor speed and rotor flux values with minimum deviations.