A periodic adaptive current controller for torque ripple reduction in uncertain permanent magnet synchronous motor drives

This paper addresses an adaptive control approach to achieve high-performance response in phase currents and to minimize torque ripples in uncertain permanent magnet synchronous motor drives. In this manner, the electrical part of the permanent magnet synchronous motor drive is considered completely uncertain by taking the inherent characteristic of the parameters into account. A periodic adaptive controller is formulated in order to achieve the torque ripple reduction in the presence of the time-varying periodic uncertainties. In the sense that the periodic uncertainties appearing in permanent magnet synchronous motor drives change by the angular position, a change of the time variable is applied in the formulation of the proposed adaptive controller, and the stability analysis is conducted accordingly utilizing a Lyapunov–Krasovskii functional. Extensive numerical simulations are successfully performed for various operation points to validate the effectiveness of the proposed method.

Torque Ripple Reduction of Switched Reluctance Motor with Non-Uniform Air-Gap and a Rotor Hole

A switched reluctance motor has a very simple structure which becomes its key signature and leads to various advantages. However, because of its double saliency and switching principle, the motor is also known to have a relatively high torque ripple, and this hinders its use as a high-performance drive. In this paper, a method to reduce torque ripple while maintaining average torque is introduced. Two elements are used to achieve this, namely, a non-uniform air-gap on the rotor-pole face and one hole in each non-uniform region, which maintains the saturation level of the air-gap. This approach preserves the mechanical simplicity of the motor and is easy to implement. Simulations and experiments were performed to verify the effectiveness of the proposed design.