Patent ID: 6153993
Filing Date: 2000-11-28
Classification: G01R,H02H,H02P

Abstract:
A control apparatus for a brushless DC motor which has a permanent magnet rotor and a 3-phase stator winding for applying a rotating magnetic field to the permanent magnet rotor, the apparatus comprising:a plurality of switching devices configured to selectively provide current patterns to the phases of the stator winding;a plurality of comparison circuits, one provided for each of the phases of the stator winding, to compare a specified reference voltage with terminal voltages of the stator winding and to output specific response patterns in response to the current patterns;a position detection circuit configured to detect a rotor position based on the outputs of the comparison circuits; andan abnormality detection circuit configured to detect abnormalities in the DC motor by comparing a particular specific response pattern output from the comparison circuits when the comparison circuits are coupled to conducting phases of the stator winding to a particular normal response pattern of the comparison circuits when the comparison circuits are coupled to the conducting phases of the stator winding,wherein a difference between the particular specific response pattern and the particular normal response pattern indicates a type of abnormality in the DC motor.