Differential Transmitting Coil Layout for Reliable Position Sensing
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Solution Overview
Problem
Existing sensor technologies, particularly those using electromagnetic flux sensing elements, face challenges in achieving optimal performance and reliability in safety-critical applications due to issues with sensor quality, failure rates, and overall functional safety.
Innovation Solution
The proposed solution involves an apparatus comprising a first transmitting coil with portions of different polarities and a second transmitting coil disposed above or below the first, configured such that when the first coil is not driven and the second is driven, a net magnetic flux through certain portions is approximately zero, entirely attributable to the second coil. Additionally, the apparatus includes a receiving coil with specific polarity configurations to enhance signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electromagnetic flux sensing elements are used, then sensor functionality is achieved, but sensor quality and reliability are insufficient for safety-critical applications
Solution Approach 1:
The transmitting coil is divided into multiple portions with different polarities (first portion with first polarity, second portion with second polarity). This segmentation allows independent control of magnetic flux generation in different spatial regions, enabling differential measurement techniques that improve both reliability and precision by canceling out common-mode errors and interference.
Solution Approach 2:
Different portions of the transmitting coil are assigned different polarities to create localized magnetic field characteristics. The first portion generates magnetic flux in one direction while the second portion generates flux in the opposite direction, allowing the system to selectively probe different regions and improve measurement accuracy through spatially-resolved sensing.
2Reliability
If multiple transmitting coils are used to improve measurement coverage, then functional safety is enhanced, but coil interaction errors increase
Solution Approach 1:
The second transmitting coil is positioned above or below the first coil and configured to generate magnetic flux that counterbalances the flux from the first coil. By driving the coils in a differential manner (one driven, one undriven), the system creates a null point or balanced state that eliminates mutual interference and allows accurate sensing of target position without coil interaction errors.
Solution Approach 2:
The transmitting coils are arranged asymmetrically in space (one above the other) with opposite polarities, creating an unbalanced magnetic field configuration that is deliberately exploited to achieve differential measurement. This asymmetric arrangement allows the system to distinguish between signals from the target and interference from the coils themselves.
3Measurement precision
If transmitting coils generate strong magnetic flux for better signal detection, then signal strength is improved, but magnetic flux leakage and interference increase
Solution Approach 1:
The magnetic flux that would normally be considered leakage or interference from the transmitting coils is converted into a useful signal by the receiving coil. The receiving coil is specifically configured to detect the magnetic flux generated by the transmitting coils and convert it into an electrical signal, transforming what would be harmful interference into beneficial measurement information.
Solution Approach 2:
The receiving coil acts as an intermediary element that couples the transmitting coils to the measurement system. It selectively receives magnetic flux from the transmitting coils and converts it into electrical signals, while being isolated from the high-current driving circuits. This intermediary function allows strong magnetic flux generation without direct electrical interference in the sensing circuitry.
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 enhances the accuracy and reliability of sensor measurements by minimizing errors associated with coil interactions and improving the signal-to-noise ratio, thereby addressing the challenges of sensor quality and functional safety in safety-critical applications.
Implementation Method 1
sensors include one or more electromagnetic flux sensing elements, such as a Hall effect element, a magnetoresistive element, or a receiving coil to sense an electromagnetic flux associated with proximity or motion of a target object
Implementation Method 2
sensors include one or more electromagnetic flux sensing elements, such as a Hall effect element
Implementation Method 3
sensors include one or more electromagnetic flux sensing elements, such as a Hall effect element, a magnetoresistive element
Data Source
AI summary
An apparatus, comprising: a first transmitting coil including at least one first portion and at least one second portion, the first and second portions having different polarities; and a second transmitting coil that is disposed above or below the first transmitting coil, the second transmitting coil including at least one third portion and at least one fourth portion, the third and fourth portions having different polarities, wherein the first and second transmitting coils are configured so that, when the first transmitting coil is not driven and the second transmitting coil is driven, a net magnetic flux through at least one of the first portions is approximately zero, the net magnetic flux being a magnetic flux that is entirely attributable to the second transmitting coil.