Magnetic angular position sensor

Abstract

The invention relates to a magnetic angular position sensor. A magnetic angular position sensor system is described herein. According to one exemplary embodiment the angular position sensor system comprises a shaft rotatable around a rotation axis, wherein the shaft has a soft magnetic shaft end portion. The system further comprises a sensor chip spaced apart from the shaft end portion in an axial direction and defining a sensor plane, which is substantially perpendicular to the rotation 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 magnetic field components in a first direction and two of the magnetic field sensor elements are spaced apart from each other and are only sensitive to magnetic field components in a second direction, and therefore the first and the second direction are mutually non-parallel and the first and second directions are perpendicular to the rotation axis.

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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