Abstract
This article presents a gain-scheduling adaptive proportional-integral speed controller for field-oriented control of hybrid stepper motor drives. The proportional-integral gains are designed to be a function of the speed error and are allowed to vary within a pre-determined range. This, therefore, eliminates the problems suffered by the conventional proportional-integral controller. The performance of the proposed gain-scheduled proportional-integral controller with field-oriented control is simulated and compared with that of the conventional fixed proportional-integral controller under starting, speed reversal, repetitive operation, and parameter variations, as well as load disturbances. The experimental system of the hybrid stepper motor drive is implemented using a digital signal processor DS1102 control board (Texas Instruments, dSPACE GmbH, Germany) to examine and evaluate the performance criterion of the proposed controller under different operating conditions. Simulation and experimental results show good improvement in transient as well as steady-state responses of the proposed controller over the conventional fixed proportional-integral one. Moreover, field-oriented control of a hybrid stepper motor modifies the dynamic performance and current distortion rather than the stepping mode of the open-loop control system.