Comparison of Two Techniques for Closed-Loop Drive of VR Step Motors Without Direct Rotor Position Sensing

Abstract:

Closed-loop control of variable reluctance (VR) step motors without using direct rotor position sensing is investigated. Two indirect rotor-position sensing techniques, namely, the waveform detection (WD) and the pulse-width modulation (PWM) were implemented and applied to a four-phase (15° step-angle) VR step motor. Test results show that a dc shunt motor and a dc series motor type of performance can be achieved from the step motor with PWM drive and WD drive, respectively. The stability problem encountered with the existing PWM controller due to motional emf effects at higher operating speeds is investigated, and modifications are suggested to include speed as an additional control signal to make the system more stable. With the inclusion of speed signal, the operating speed of the test motor is improved from 1000 to 1750 r/min. Comparison of performance from both techniques along with experimental results are also presented. © 1991 IEEE

Año de publicación:

1991

Keywords:

Fuente:

scopus