Angle Sensor Magnetic Anisotropy Harmonic Error Reduction
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Solution Overview
Problem
Magnetic angle sensors face errors in detected angle values due to distortions in the rotating magnetic field and magnetic detection element characteristics, leading to angular errors that are challenging to mitigate without increasing system complexity.
Innovation Solution
The angle sensor system incorporates a magnetic field generation unit producing a rotating magnetic field with orthogonal components, utilizing first and second magnetic detection elements with specific magnetic anisotropies to generate detection signals that reduce errors caused by harmonic components, and an angle detection unit for error correction processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple detection circuits with different phases are used to reduce angular error, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent changes the magnetic anisotropy parameter of the magnetic detection element to align the easy axis of magnetization with the first direction. This parameter change allows the detection element to inherently generate a first detection signal corresponding to the cosine of the rotating magnetic field direction, eliminating the need for multiple phased detection circuits while maintaining angular error reduction capability
2Measurement precision
If magnetic anisotropy is utilized to reduce harmonic-related errors, then measurement precision improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating specific magnetic anisotropy properties in the magnetic detection element. The easy axis of magnetization is oriented in the first direction through controlled magnetic anisotropy, giving the detection element a localized directional sensitivity that enables it to inherently distinguish the cosine component of the rotating magnetic field, thereby reducing angular error without requiring complex external alignment mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces angular errors associated with the rotating magnetic field while maintaining a simple system configuration, improving the accuracy of detected angle values by aligning the magnetic anisotropies to minimize harmonic-related errors.
Implementation Method 1
The magnetic detection element includes a magnetic layer provided with magnetic anisotropy, and a resistance value of the magnetic detection element varies according to a direction of the rotating magnetic field
Data Source
AI summary
An angle sensor system includes a magnetic field generation unit for generating a rotating magnetic field, and an angle sensor for detecting the rotating magnetic field to generate a detected angle value. The rotating magnetic field contains first and second magnetic field components orthogonal to each other. Each of the first and second magnetic field components contains an ideal magnetic field component, and an error component corresponding to the fifth harmonic of the ideal magnetic field component. The angle sensor includes first and second detection signal generation units. Each of the first and second detection signal generation units includes a magnetic layer whose magnetization direction varies according to the direction of the rotating magnetic field. The magnetic layer is provided with a magnetic anisotropy that is set to reduce an angular error resulting from the error components of the first and second magnetic field components.