Magnetic device for determination of angular position in a multiphase rotary electrical machine

摘要

Disclosed is the selecting of the optimum characteristics of a magnetic device producing a sinusoidal signal for determination of angular position in a rotary machine. The device includes a multi-polar magnetic ring which is mobile in rotation around an axis, and creates a variable magnetic field according to an angle of rotation. In close proximity to the magnetic ring, a magnetic sensor is placed in this magnetic field, and generates the sinusoidal signal. The air gap between the sensor and ring is constituted by spacing the sensor by a distance E from the magnetic ring on a radial plane. Optimum performance is achieved when a first ratio e/E of a thickness e of the multi-polar magnetic ring in a direction which is radial relative to the air gap E is between 0.4 and 2.3. A second ratio h/e of a height h of the ring, in a direction which is axial relative to the thickness e, is between 1.5 and 8.

主权项

1. A magnetic device (1) associated with a multiphase rotary electrical machine, the device (1) comprising:
a multi-polar magnetic ring (2) mobile in rotation around an axis (R′R) and creating a variable magnetic field (B) according to an angle of rotation (0); a plurality of magnetic sensors (3) placed in the variable magnetic field (B), wherein said plurality of magnetic sensors (3) are coupled to the multiphase rotary electrical machine and each sensor generates a sinusoidal signal, where said signals generated by the plurality of magnetic sensors control a phase current switching function of the multiphase rotary electrical machine; and an air gap (4) formed by spacing each sensor by a distance E from said magnetic ring on a radial plane (XOY); wherein a first ratio e/E of a thickness e of said magnetic ring (2) in a direction (OX) is radial relative to the air gap E is between 0.4 and 2.3, and the multi-polar magnetic ring (2) includes a plurality of angularly spaced alternating magnetic poles.