# An NUTSF at Sub-Region for Suppression of Torque Ripple in Switched Reluctance Motors
## 6 Experimental Verification  
The experimental platform to verify the proposed TSF control strategy is shown in Figure 14. The TSF control strategy is implemented at the TMS320F28335 DSP platform, the rotor position is measured by an encoder with a 15-bit absolute value, the load acts as a magnetic brake and the asymmetrical half-bridge converter is employed to drive the SRM. The parameters of the SRM prototype are consistent with those in the simulation experiment.  
The conventional exponential TSF and the proposed control strategy are compared and verified in order to verify the correctness of the proposed strategy. The load torque is set to 5 N\(\cdot\)m, and the SRM operates at 500 r/min and 1000 r/min, respectively.  
The waveforms of the current and torque of the SRM are shown in Figure 14(a),b and Figure 15(a),b when the SRM operates at 500 r/min. Figures 15 and 15 are obtained from the conventional exponential TSF control strategy and the proposed control strategy, respectively. Comparing Figure 14(b) with Figure 15(b), the torque ripple of the conventional exponential TSF control strategy is 30%, and the NUTSF control strategy is 19%. The results show that the NUTSF control strategy can reduce torque ripple effectively.  
The waveforms are shown in Figure 17a,b and Figure 18a,b when the SRM operates at 1000 r/min. Figures 17 and 18 are obtained from the conventional exponential TSF control strategy and the proposed control strategy, respectively. Comparing Figure 17b with Figure 18b, the torque ripple of the conventional exponential TSF control strategy is 70%, and the NUTSF control strategy is 22%. The results show that the proposed control strategy can effectively suppress torque ripple when the speed increases.  
According to Figures 15 and 16, when the load torque is 5 N\(\cdot\)m at 500 rpm, the torque ripples of the conventional TSF and the NUTSF are 30% and 19%, respectively, and the peak currents are 14 A and 12 A, respectively. Corresponding to the torque ripples of 21% and 15% and the peak currents of 15 A and 12 A in the simulation results of Figure 12. According to Figures 17 and 18, when the load torque is 5 N\(\cdot\)m at 1000 rpm, the torque ripples of the conventional TSF and the NUTSF are 70% and 22%, respectively, and the peak currents are 15 A and 10 A, respectively. Corresponding to the torque ripples of 62% and 18% and the peak currents of 15 A and 11 A in the simulation results of Figure 13. This indicates that the simulation results of peak current, current waveform and torque ripple are consistent with the experimental results under the same experimental conditions. The  
Figure 16: Waveforms of NUTSF at 500 r/min: (**a**) current; (**b**) torque.  
Figure 17: Waveforms of conventional TSF at 1000 r/min: (**a**) current; (**b**) torque.  
Figure 18: Waveforms of NUTSF at 1000 r/min: (**a**) current; (**b**) torque.  
conventional TSF control strategy produces larger torque ripple owing to the weak ability of torque tracking. The control strategy proposed in this paper has good performance of tracking torque and suppressing torque ripple.