Rotating Field Sensor Signal Correction for Angle Error Reduction
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Solution Overview
Problem
Rotating field sensors with magnetic detection elements face errors in detecting angles due to induced magnetic anisotropy of the free layer, causing arbitrary phases in error components of output signals, which existing correction methods cannot account for.
Innovation Solution
A rotating field sensor design that includes a signal generation unit and an angle detection unit, where the angle detection unit calculates a detected angle value by generating and correcting signals based on the sum of squares of signal components, estimating and subtracting error components to reduce errors even when their phases are arbitrary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional angle detection methods are used with MR elements, then the sensor can detect the rotational position, but the detected angle includes errors due to waveform distortion from induced magnetic anisotropy
Solution Approach 1:
The patent implements feedback by detecting the actual output signals from MR elements, analyzing their waveform characteristics, and using this information to correct the angle detection results. The system continuously monitors the output signals and adjusts the detection algorithm to compensate for waveform distortion, ensuring accurate angle measurement despite signal degradation.
Solution Approach 2:
The patent changes the detection parameters by transitioning from direct angle calculation based on ideal sinusoidal waveforms to a corrected detection method that accounts for actual waveform characteristics. The system modifies the detection algorithm to use corrected sine and cosine values derived from the distorted waveforms, thereby maintaining measurement accuracy under varying magnetic field conditions.
2Measurement precision
If correction sensing elements are added to reduce error signals, then the angle detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical approach of adding physical correction sensing elements with a signal processing approach. Instead of increasing hardware complexity with additional sensors, the system uses mathematical correction methods and signal analysis to achieve the same error reduction effect, thereby maintaining simplicity while improving accuracy.
Solution Approach 2:
The patent introduces an intermediary correction mechanism in the signal processing domain. Rather than adding physical components, the system uses intermediate calculation steps that correct the distorted waveforms before final angle determination, effectively mediating between the distorted sensor output and the required accurate angle measurement.
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 approach effectively reduces errors in detected angles by accounting for arbitrary phase error components, improving the accuracy of angle detection in rotating field sensors.
Implementation Method 1
The rotating field sensors use magnetic detection elements to detect the angle that the direction of the rotating magnetic field forms with respect to a reference direction
Data Source
AI summary
An angle detection unit including first to third arithmetic units receives first and second signals that are associated with intensities of components of a rotating magnetic field in mutually different directions. The first arithmetic unit generates a sum of squares signal made up of the sum of squares of the first and second signals. Based on the sum of squares signal, the second arithmetic unit calculates a first error component estimate which is an estimated value of a first error component included in the first signal and a second error component estimate which is an estimated value of a second error component included in the second signal. The third arithmetic unit generates a first corrected signal by subtracting the first error component estimate from the first signal, generates a second corrected signal by subtracting the second error component estimate from the second signal, and calculates a detected angle value based on the first and second corrected signals.