Patent ID: 8078425

Claim:
A device for detecting an angular position of a rotor of a polyphase rotary electrical machine containing a stator and a plurality of magnetic field sensors, fixed with respect to the stator and capable of delivering first signals representing a rotating magnetic field detected by said sensors, comprising: means for generating ( 201 ), from linear combinations of said first signals ( 2001 - 2003 ), at least a first sinusoidal signal ( 2010 ) phase-shifted by a fixed value φ 1 and a second sinusoidal signal ( 2011 ) phase-shifted by a fixed value φ 2 , wherein a fixed phase shift value φ is different from zero and from 180°, and wherein said sinusoidal signals represent a real angular position of the rotor ( 100 ); means for detecting an estimated angular position value of the rotor ( 100 ) by locking from said real angular position using a feedback tracking loop and injecting at least a third and a fourth sinusoidal signals as an input, wherein said third and fourth sinusoidal signals are determined based on said estimated angular position value and are phase-shifted from said fixed phase shift value φ; means for multiplying ( 208 ) said first sinusoidal signal and said third sinusoidal signal to obtain a first result ( 2080 ); means for multiplying ( 209 ) said second sinusoidal signal and said fourth sinusoidal signal to obtain a second result ( 2090 ); and means for subtracting ( 210 ) said first and second results, so that the following relation is satisfied at any instant: sin(θ real +φ 1 )·sin(θ est +φ 2 )−sin(θ real +φ 2 )·sin(θ est +φ 1 )=sin(φ 2 −φ 1 )·sin(θ real −θ est ), wherein θ real and θ est are said real and estimated angular positions, φ 1 and φ 2 are phase shifts of said first and second sinusoidal signals in relation to a reference marker (RRef θ) linked to said stator ( 104 ) and said fixed phase shift φ being equal to (φ 2 −φ 1 ).