Patent ID: 7990090

Claim:
Method of determining the position of a rotor ( 4 ) of a machine ( 1 ), the rotor being provided with at least one excitation winding ( 25 ), the excitation winding being connected to a chopper ( 6 ), the machine comprising n stator windings, n being an integer number, the rotor being magnetically coupled with each of the n stator windings of the machine, this machine being connected to a control device ( 2 ) able to control it in full wave mode or pulse width modulation mode, characterised in that the method comprises the following steps: inhibition of the control device, application of an excitation voltage variable over time to the rotor, by means of the chopper, measurement of an induced electromotive force (e 1 , e 2 or . . . e n ) in each of the stator windings, determination of a position of the rotor at rest or at low speed, from at least an operation of comparing the induced electromotive forces with each other and at least one operation of comparing an induced electromotive force and a common reference, implementation of the commands of the control device, according to the position of the rotor determined.