Magnetic Angle Position Sensor

Abstract

The present invention relates to magnetic angular position sensors. A magnetic angular position sensor system is described herein. According to an exemplary embodiment, the angular position sensor system comprises a shaft rotatable about an axis of rotation, wherein the shaft has a soft magnetic shaft end. The system also includes a sensor chip axially spaced from the shaft end and defining a sensor plane substantially perpendicular to the rotational axis. At least four magnetic field sensor elements are integrated in the sensor chip, wherein two of the magnetic field sensor elements are spaced apart from each other and are only sensitive to a magnetic field component in a first direction, and wherein two of the magnetic field sensor elements are spaced apart from each other and are only sensitive to a magnetic field component in a second direction, whereby the first and second directions are non-parallel to each other and the first and second directions are perpendicular to said axis of rotation.

Description

technical field [0001] The present invention relates generally to angular position sensors utilizing magnetic field sensors to measure angular values, and more particularly to on-axis angular position sensors, systems and methods having various applications, including in brushless direct current (DC) motors application. Background technique [0002] Magnetic field sensors can be used to sense the angular position of a shaft or other object. For example, a permanent magnet may be mounted on the shaft, and a magnetic field sensor may be arranged proximate to the magnet to sense the magnetic field generated by the magnet as it rotates with the shaft. When a magnetic field sensor is mounted close to the shaft at a specific distance from the axis of rotation of the shaft, the sensor is often referred to as an "off-axis" magnetic angular position sensor. Off-axis magnetic angular position sensors are often implemented when the front side of the shaft is not accessible (eg due to...

AI Technical Summary

Problems solved by technology

BLDC motors present a challenging environment for magnetic field sensors because they typically include strong rotating magnets and copper windings carrying high currents, both of which generate a time-varying magnetic field that interferes with the magnetic field used to measure angular position and resulting in measurement errors

These interfering magnetic fields are strongly inhomogeneous, which makes it difficult to eliminate their influence on angular position measurements

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