Improved Current Profile Selection for Noise Reduction of Switched Reluctance Motor at Middle Speed Considering Back EMF

An improved current profile selection for noise reduction of a switched reluctance motor (SRM) during middle-speed operation is presented with the principle of flattening the three-phase radial force sum. The improved current is selected from the proposed algorithm, which considers the limited input voltage and back electromotive force influence at middle-speed operation. The improved current profile is compared with the single pulse current, which is the typical current for SRMs at middle-speed operation. The analysis results show that the variation of the radial force sum by the improved current profile is less than that of the single pulse current, although the influence of the back electromotive force is high. The effectiveness of radial force sum flattening is verified by the experimental results. The experiments were carried out with the downscaled operating point of a SRM owing to the limited range of the operating speed. The experiment results show a significant reduction in the highest and second-highest peak noises at 5.4 and 1.8 kHz by 11.04 and 17.51 dB, respectively, with the improved current profile. The other noises were also reduced.