Micro-stepping control of a two-phase linear stepping motor with three-phase VSI inverter for high-speed applications

This paper presents a synchronous frame current control scheme for micro-stepping of two-phase linear stepping motor drive using three-phase voltage source inverter. Due to the wide operating frequency the frequency dependent voltages are decoupled from the controller in order to reduce the current following errors and to preserve the dynamical characteristics as frequency varies. A motor cogging force compensation scheme performed in the synchronous frame is proposed to reduce the positioning error and the velocity ripple caused by detent force. A space vector PWM scheme is used for the modulation of motor voltage. The scheme is based on the principle of harmonic injection originally derived for three-phase motor drives. Good static and dynamic performances were obtained in the experimental verifications.