Stepping motor control system and method for controlling a stepping motor using closed and open loop controls

摘要

A stepping motor is driven in both closed-loop and open-loop modes while initiating microstepping after a predetermined threshold velocity has been reached. A feedback device such as an encoder is mounted on the stepping motor shaft and the encoder keeps track of the mechanical position of the rotor. Based on feedback from the encoder, stator phases are activated to maintain a 90° phase advance and produce maximum torque. A lead angle compensation technique is used to advance the motor lead angle, to allow for the excitation currents to reach maximum even at higher speeds. The stepping motor controller employs this strategy in order to produce maximum torque across a wide range of motor speeds and actuator motions.