Patent ID: 6459230
Filing Date: 2002-10-01
Classification: H02P

Abstract:
A method of reconnecting a motor to a motor drive comprising:(A) controlling a current which flows through the motor using a current regulator, the current regulator producing a voltage command output based on a current command input; (B) commanding a current at the current command input of the current regulator; (C) acquiring back EMF measurements at different instants in time by monitoring the voltage command output of the current regulator; (D) determining back EMF phase angles for a plurality of the instants in time based on a respective plurality of the back EMF measurements; (E) determining a frequency of the back EMF based on the back EMF angles determined for the plurality of instants in time; and (F) reconnecting the motor drive to the motor based on the frequency of the back EMF; wherein the current that is controlled during the controlling step (A) is a first current, the current regulator is a first current regulator, the voltage command output is a first voltage command output, and the current command input is a first current command input; wherein the method further comprises (1) controlling a second current which flows through the motor using a second current regulator, the second current regulator producing a second voltage command output based on a second current command input, and (2) commanding a current at the second current command input of the second current regulator; wherein, during the acquiring step (C), a plurality of back EMF measurements are acquired each different instant in time, including a first back EMF measurement acquired by monitoring the first voltage command output of the first current regulator and a second back EMF measurement acquired by monitoring the second voltage command output of the second current regulator; and wherein the determining step (D) includes comparing the first and second back EMF measurements.