Reconstruction of BEMF signals for synchronizing the driving of brushless- sensorless motors by means of predefined driving signals

摘要

The sensing of BEMF signals in the motor's windings for synchronizing the phase switchings, in driving a brushless and sensorless motor with predefined constant voltage or current values or predefined voltage or current profiles stored permanently in a memory, is greatly simplified through a reconstruction technique that avails itself of the knowledge of the predefined drive values. The sensing does not require access to the center star point and is performed by sensing either the voltage difference between the terminals of two windings or of the current flowing in two windings, depending on whether a current or voltage mode is employed.