Torque Control Method for Switched Reluctance Motor based on Equivalent Inductance of Magnetic Co-energy

Abstract

This paper proposes a torque ripple suppression method for a switched reluctance motor (SRM) with only measurable parameters. A large third-order torque ripple is generated via a conventional method with constant dq0-axis current, which is the dq-axis current and zero-phase current converted from the three-phase current of the SRM. The proposed method derives the zero-phase current with the third-order harmonic to suppress the torque ripple from a torque equation by considering the spatial harmonics of the inductance profile up to the fourth order and torque/current ratio in the entire region. Additionally, the average torque equation is derived from the inductance expressing the magnetic co-energy at the magnetic saturation. Consequently, the experimental results confirm that the torque ripple is reduced by 86.5% in the linear region and by 83.2% in the magnetic saturation region compared to the conventional method with the constant dq0-axis current. Finally, the derived average torque equation agrees with the experimental results, including the error of 5.2%.