Patent ID: 7246029
Filing Date: 2007-07-17
Classification: H02P

Abstract:
1. A system for determining a position angle of an electric machine having a rotor and a stator, the system comprising: a plurality of windings; a circuit configured to create a pulse current in at least three stator windings of the plurality of windings; at least one voltage sensor, each sensor being configured to sense a pulse field response in a corresponding winding of the plurality of windings; a processor in communication with the at least one sensor and configured to determine the position angle of the rotor based on the pulse field response; and wherein the processor is configured to determine the position angle based on the relationship F_A=I_field*L_FA=I_field*L*sin(theta), F_B=I_field*L_FB=I_field*L*sin(theta−120°), F_C=I_field*L_FC =I_field*L*sin(theta−240°), where: F_A, F_B, F_C are flux linkage of phase A, B, C; L_FA, L_FB, L_FC are mutual inductances between rotor coil and phase A, B, C; I_field is rotor coil field current; L is a constant; theta is the rotor angle position.