Nitinkumar B Patel

US Patent:

60086181, Dec 28, 1999

Filed:

Nov 26, 1997

Appl. No.:

8/979021

Inventors:

Bimal Kumar Bose - Knoxville TN
Nitinkumar Ratilal Patel - Long Beach CA
Kaushik Rajashekara - Carmel IN

Assignee:

General Motors Corporation - Detroit MI

International Classification:

H02P 700
H02P 540

US Classification:

318811

Abstract:

An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.