Microcomputer implementation of optimal algorithms for closed-loop control of a hybrid stepper motor drives

Abstract

Optimal control algorithms for closed-loop control of a hybrid stepper motor drive and their microcomputer implementations are discussed. An analytical expression for the average torque of a two-phase hybrid stepper motor with bipolar supply and current controller is developed. Approximate and exact expressions for the optimal control angle of a two-phase hybrid stepper motor with bipolar supply and current controller are derived. An actual hybrid stepper motor drive and the microcontroller-based implementation of the proposed optimal control algorithms are described. The experimental results obtained by positioning of a two-phase hybrid stepper motor drive with phase current controller and incremental encoder suggest that the proposed optimal control algorithms provide maximum acceleration and minimum positioning time of the hybrid stepper motor drive.