Detecting load torque and determining stepper motor drive current optimization involves setting drive current amplitude to bring measured transition voltage duration into agreement with target duration

摘要

The method involves reading out the voltage at the nodes (N1-N5) between each pair of series-connected windings (L1-L5) whilst the motor is running at a given speed to detect transition voltage regions that occur after stimulation of the windings by the drive current; measurement of the duration of the detected transition voltage regions; setting at least one target duration; comparing at least one measured duration with the target duration; setting the amplitude of the drive current if necessary to bring the measured duration into agreement with the target duration. An independent claim is also included for an arrangement for controlling the operation of a stepper motor and for a motor system with a stepper motor.