Direct-Read Meter Magnetic Interference Correction Matrix
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Solution Overview
Problem
Direct-read electronic flow meters with multiple permanent magnet rotating wheels face magnetic interference issues, leading to non-linear magnetic field angle calculations due to proximity of the wheels, which complicates the magnetic circuit and increases manufacturing costs when soft magnetic materials are used for shielding.
Innovation Solution
A direct-read meter system that employs N permanent magnet rotating wheels and N biaxial magnetic angle sensors, using a correction matrix [Cij] to eliminate interfering magnetic fields from raw output signals, converting them into precise rotation angle measurements without relying on magnetic shielding, by forming a raw signal matrix [V/Vp]k(i)raw and performing arithmetical operations to isolate the intended magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple permanent magnet rotating wheels are placed close together, then the device size is reduced, but magnetic interference between wheels increases causing non-linear measurement errors
Solution Approach 1:
The patent converts the harmful magnetic interference into a useful signal by using the interfering magnetic fields from adjacent wheels as reference inputs. The computation element processes these interference signals through the correction matrix to calculate and remove the interference components, transforming the previously harmful magnetic coupling into a beneficial source of correction data that improves measurement linearity.
Solution Approach 2:
The patent changes the measurement parameters by using biaxial magnetic angle sensors that detect both X and Y axis magnetic field components, creating a two-dimensional measurement space. This parameter expansion allows the system to distinguish between the intended magnetic field and interfering fields through mathematical processing, maintaining measurement precision despite close wheel spacing.
2Object-affected harmful factors
If soft magnetic shielding materials are introduced between permanent magnet rotating wheels, then magnetic interference is reduced, but manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical/physical magnetic shielding approach with a computational/electronic solution. Instead of using soft magnetic materials to physically block or redirect magnetic fields, the system uses biaxial sensors to detect magnetic field components and a computation element with correction matrices to mathematically eliminate interference, substituting physical shielding with digital signal processing.
Solution Approach 2:
The computation element acts as an intermediary that processes the raw magnetic sensor outputs. It receives both the intended magnetic field signals and interfering magnetic field signals, applies correction matrices to separate and eliminate interference components, and produces corrected rotation angle measurements, serving as a mediator between the magnetic fields and the final measurement output.
3Object-affected harmful factors
If soft magnetic shielding materials are introduced between permanent magnet rotating wheels, then magnetic interference is reduced, but the magnetic circuit becomes more complex
Solution Approach 1:
The patent replaces the complex magnetic circuit design with a simpler computational approach. Instead of designing complex magnetic shielding structures and managing complicated magnetic flux paths through soft magnetic materials, the system uses straightforward biaxial magnetic field detection combined with mathematical correction, significantly reducing magnetic circuit complexity while maintaining interference rejection capability.
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 enhances measurement precision by reducing non-linear components in output signals, maintaining constant magnetic field magnitudes, and improving the accuracy of rotation angle calculations, while avoiding the need for soft magnetic shielding materials.
Implementation Method 1
the ith magnetic angle sensor sensing, along an X axis and a Y axis perpendicular to each other, a linear superposition of an intended magnetic field produced by the ith permanent magnet rotating wheel and interfering magnetic fields produced by the other N−1 permanent magnet rotating wheels
Data Source
AI summary
A direct-read meter capable of eliminating magnetic interference of adjacent rotating wheels, comprising N coaxial rotating wheel permanent magnets and corresponding magnetic angle sensors, a sampling element, a storage element, and a computation element. The magnetic angle sensors sense a linear superposition of the magnetic field from the intended permanent magnet rotating wheel and the interfering magnetic fields from the other rotating wheel permanent magnets. The sampling element samples the output signals of the N magnetic angle sensors to form a N*1 raw signal matrix [V/Vp]k(i)raw. The storage element stores an N*N correction matrix [Cij]; and the computation element computes the correction signal matrix [V/Vp]kcorr(i)=[V/Vp]k(i)raw−sum{C(i, j)*[V/Vp]k(j)raw}, thus eliminating the interfering magnetic field and permitting calculation of the rotation angle of the rotating wheel permanent magnets. This direct-read meter has the advantages of simple calculation, high precision, and elimination of the need for magnetic shielding.