Interlayer Coupling Detection Coil for Metal Object Sensing
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Solution Overview
Problem
Existing metal object detection systems face challenges in accurately detecting small-size metal objects like coins and clips due to non-detection blind zones and poor detection sensitivity, especially in wireless power transmission systems where conductive objects can be heated by alternating magnetic fields, posing safety hazards.
Innovation Solution
A detection coil structure based on interlayer coupling with a top and bottom sub-detection coil arranged orthogonally, where the coils are connected through terminals and switches to change mutual inductance modes, allowing for improved detection sensitivity and elimination of blind zones by synthesizing results from adjacent coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single-layer detection coils are used, then the structure is simple, but the detection sensitivity for small-size metal objects is poor and blind zones exist
Solution Approach 1:
The patent transitions from a single-layer detection coil to a multi-layer interlayer coupling detection coil structure. By adding the vertical dimension (multiple layers stacked together), the detection coverage is expanded and blind zones are eliminated while maintaining reasonable structural complexity through standardized coil designs.
Solution Approach 2:
The patent combines multiple detection coils into an interlayer coupling structure where coils are stacked in layers with coupling between layers. This merging approach maintains detection sensitivity while reducing the overall footprint and eliminating blind zones through cooperative detection across layers.
2Reliability
If detection coils are densely laid in multiple layers, then blind zones are eliminated, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The detection system is segmented into multiple independent but coupled layers, each layer containing detection coils that can be manufactured and assembled separately. This segmentation allows for standardized production of each layer while achieving comprehensive coverage when combined, simplifying the overall manufacturing process compared to creating a single complex multi-layer structure.
3Measurement precision
If metal objects are detected using traditional coils, then the detection process is simple, but small-size and remote metal objects cannot be detected accurately
Solution Approach 1:
By stacking detection coils in multiple layers with interlayer coupling, the system creates a three-dimensional detection field that extends coverage in the vertical dimension. This allows small-size and remote metal objects that would be missed by single-layer coils to be detected through the expanded detection volume and enhanced magnetic field interaction.
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
The interlayer coupling detection coil structure significantly enhances detection accuracy for small-size metal objects by amplifying impedance variations and reducing magnetic flux and induced voltage, ensuring safety in wireless power transmission systems and increasing signal-to-noise ratios.
Implementation Method 1
a transmitting coil is excited by an alternating current to generate an alternating magnetic field
Implementation Method 2
Conductive objects will be heated due to the eddy current effect
Implementation Method 3
A detection coil structure based on interlayer coupling with a top and bottom sub-detection coil arranged orthogonally, where the coils are connected through terminals and switches to change mutual inductance modes
Data Source
AI summary
The disclosure discloses a detection coil structure based on interlayer coupling and a metal object detection system. The detection coil structure includes: a top sub-detection coil and a bottom sub-detection coil, wherein the top and bottom sub-detection coils are the same in structure and similar or same in size and are orthogonal to each other, and both the outer boundaries and geometric symmetry centers of the detection coils are completely coincident; the top sub-detection coil includes a first terminal, a second terminal, a third terminal and a fourth terminal, and the bottom sub-detection coil includes a fifth terminal, a sixth terminal, a seventh terminal and an eighth terminal; and the first terminal is connected to the second terminal, the seventh terminal is connected to the eighth terminal, and the third terminal and the fourth terminal are respectively connected to the fifth terminal and the sixth terminal. When there is no metal object near the coil, the top and bottom sub-detection coils are completely decoupled, and the mutual inductance is zero. When there is a metal object near the coil, the detection coil structure can significantly amplify the impedance variation of the metal object to the entire detection coil to improve the detection effect by means of the mutual inductance coupling effect between the top and bottom sub-detection coils, and at the same time, a staggered arrangement structure can further eliminate non-detection blind zones.