Patent ID: 6441572
Filing Date: 2002-08-27
Classification: H02P

Abstract:
A method for determining the rotor position in a motor at standstill in a motor having multiple phase windings arranged as a stator and a permanent magnet rotor, comprising the steps of:applying a test voltage of a first and second polarity across a first pair of said stator phase windings for selectively establishing a current flow through said first phase pair and holding a remaining phase winding open; measuring a voltage response to the application of said test voltage across said first phase pair at said remaining open phase winding; applying a test voltage of a first and second polarity across a second pair of said stator phase windings for selectively establishing a current flow through said second phase pair and holding a remaining phase winding open; measuring a voltage response to the application of said test voltage across said second phase pair at said remaining open phase winding; and determining the rotor position of the motor at standstill based on the magnitude of the measured responses across the open phases of said motor in response to said applied voltages.