Magnetic Position Sensor Irregular Pole Field Correction
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Solution Overview
Problem
Existing magnetic sensors for detecting angular positions, particularly in automotive ignition systems, face challenges in achieving high precision and coding accuracy due to irregular poles with different spacings and magnetization, leading to unstable differential signals.
Innovation Solution
Incorporating means to correct the magnetic field value of irregular poles, ensuring the differential signal slopes are identical to those of regular poles, thereby stabilizing the signal and enhancing coding precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an irregular pole with different spacing is introduced to increase coding possibilities, then coding accuracy is improved, but the differential signal becomes unstable and measurement precision deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the magnetization strength of the irregular pole. Specifically, the magnetization of the irregular pole is adjusted to a value different from regular poles (e.g., 0.8 times the regular magnetization) to compensate for the spacing difference, thereby stabilizing the differential signal slope and maintaining measurement precision while preserving enhanced coding capabilities
Solution Approach 2:
The patent applies local quality by creating distinct magnetic field characteristics at different locations on the encoder ring. Regular poles maintain standard magnetization values while the irregular pole has a specifically adjusted magnetization value, allowing each region to contribute optimally to either coding resolution or signal stability depending on its local requirements
2Measurement precision
If the magnetization of irregular pole is adjusted to stabilize differential signal, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by precisely controlling the magnetization strength of irregular poles during the manufacturing process. This allows the irregular poles to generate a corrected magnetic field that stabilizes the differential signal slope, improving measurement precision without requiring additional correction mechanisms or increasing overall device complexity
Solution Approach 2:
The patent applies self-service by designing the irregular pole's magnetization to inherently compensate for its own spacing irregularity. The adjusted magnetization value enables the irregular pole to self-correct the differential signal distortion it would otherwise cause, eliminating the need for external correction circuits or complex control 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 approach stabilizes the differential signal, allowing for improved coding accuracy and precision in detecting irregular poles, maintaining high measurement precision while increasing coding possibilities.
Implementation Method 1
The detection cell, such as a Hall effect probe, for example, delivers a periodic sinusoidal signal
Implementation Method 2
the irregular pole comprises means for correcting the value of its magnetic field, so as to stabilize the differential signal
Data Source
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Figure 3A~4B
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AI summary
The invention relates to a position sensor characterized in that the irregular pole (Pi) includes means (10) for correcting the value of its magnetic field, so as to stabilize the differential signal, so that the part of the differential signal taken at the zero crossing and located between the parts of the differential signal corresponding to the crossings of the adjacent poles has a slope whose value, in absolute value, is substantially identical to the values of the slopes of the parts of the differential signal taken at the zero crossing and corresponding to the crossings of the other poles.