Instantaneous Current Profile Control of Four-Phase SR Motor for Industrial Servo Drives

Abstract

This paper presents instantaneous current profile control of a four-phase switched reluctance (SR) motor for servo drive applications. Generally, a positioning controller for servo drives has torque and adjustable-speed regulators as its inner loop. The proposed instantaneous current controller works as the torque regulator of the SR motor in the low-speed range less than 10% of the rated speed on the assumption that it switches to or from a different torque regulator beyond or within the threshold speed. The proposed instantaneous current controller enables the suppression of the inherent torque ripple of the SR motor and employs voltage PWM control with a fixed switching frequency for tracking the instantaneous current profile with respect to given torque reference. Experimental studies using a 400W SR motor with a four-phase 8/6 configuration demonstrate the effectiveness of the proposed instantaneous current profile controller as the inner loop of the positioning controller for servo drives.