Patent ID: 6861966
Filing Date: 2005-03-01
Classification: G01P,H02P

Abstract:
1. A method for providing a digital current signal from an analog armature current signal of a motor, the analog armature current signal having current ripples, the method comprising: subjecting the analog armature current signal to an analog-to-digital conversion based on a threshold value in order to produce a first digital current signal having current pulses for each current ripple of the analog armature current signal; during a transient phase of operation of the motor, sampling the analog armature current signal at a predetermined sampling rate which is greater than an expected rate of the current ripples of the analog armature current signal in order to produce a second digital current signal having current pulses for each current ripple of the analog armature current signal during the transient phase of operation of the motor; comparing the current pulses of the first and second digital current signals; and evaluating the current pulses of the second digital current signal which are in non-conformance with the current pulses of the first digital current signal.