STABILIZATION OF VARIABLE-RELUCTANCE MOTOR DRIVES OPERATING WITHOUT SHAFT POSITION FEEDBACK.

This paper describes a technique for stabilizing the operation of variable-reluctance stepping-motor drives operating without a shaft-position sensor. In such systems there is a trade-off between the system efficiency and the torque margin (or pullout torque) which depends on the width of the conduction pulse. The scheme described in the paper permits the motor to run in the steady state with narrow conduction angles and high efficiency. Under transient or overload conditions the conduction pulse is increased in response to a change in the dc link current, providing an increase in available torque. Tests on a small motor drive have produced a steady-state torque margin of over 300% and of 200% under step-change conditions.

STABILIZATION OF VARIABLE-RELUCTANCE MOTOR DRIVES OPERATING WITHOUT SHAFT POSITION FEEDBACK. Conference Paper