Miniaturized Fluxgate Sensor Coil Design
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Solution Overview
Problem
Existing magnetic flux detection systems, such as fluxgate systems, face challenges in producing a homogeneous magnetic field and achieving high detection sensitivity due to the limited number of windings and rapid field strength drop between coil windings, especially in micro-electromechanical systems (MEMS) on semiconductor substrates.
Innovation Solution
The system optimizes magnetic field homogeneity and detection sensitivity by distributing windings suitably between excitation and pickup coils, using magnetic thin films, and implementing additional flux-detecting coils in series or parallel configurations to maximize winding numbers and reduce electric resistance, thereby enhancing field homogeneity and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the number of windings is increased to improve magnetic field homogeneity, then field homogeneity improves, but device complexity and manufacturing difficulty increase due to limited space in MEMS structures
Solution Approach 1:
The patent implements pickup coil windings nested within the excitation coil windings, with pickup coil windings disposed between adjacent excitation coil windings. This nested configuration allows both coils to share the same spatial envelope, maximizing the number of effective windings for magnetic field generation while maintaining a compact MEMS footprint and avoiding increased device complexity.
Solution Approach 2:
The patent transitions from planar coil configurations to three-dimensional nested coil structures. By positioning pickup coil windings in the spaces between excitation coil windings in multiple layers, the design effectively utilizes vertical and lateral dimensions simultaneously, achieving higher winding density and improved field homogeneity without proportionally increasing device area.
2Force
If the gap between adjacent windings is reduced to improve magnetic field strength, then field strength improves, but manufacturing precision requirements increase due to minimum structure width constraints
Solution Approach 1:
The patent optimizes the spatial distribution of windings locally, positioning pickup coil windings specifically in the regions between adjacent excitation coil windings where magnetic field density is highest. This local optimization maximizes magnetic field strength in critical regions without requiring uniform reduction of all gaps, thereby maintaining manufacturability within minimum structure width constraints.
3Measurement precision
If additional flux-detecting coils are added to improve detection sensitivity, then detection sensitivity improves, but device complexity and power consumption increase
Solution Approach 1:
The nested coil structure serves multiple functions simultaneously: the excitation coils generate the primary magnetic field for magnetizing the magnetic core, while the nested pickup coils detect magnetic flux changes. This multi-functional design improves detection sensitivity without requiring separate dedicated detection coil systems, thereby avoiding proportional increases in power consumption and device complexity.
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 enables the generation of extremely homogeneous magnetic fields with high detection sensitivity in magnetic cores, reducing power output requirements and improving field detection capabilities while maintaining cost-effectiveness and low space requirements.
Implementation Method 1
The excitation element includes a coil, which is operated using an alternating current featuring an excitation frequency. A magnetic flux in accordance with the magnetic hysteresis curve (B-H-curve) having the same frequency as the excitation frequency of the alternating current is generated in the magnetic core.
Implementation Method 2
The magnetic flux density B in a ferromagnetic material is defined by the strength of the surrounding magnetic field H. The magnetic flux in the magnetic core is proportional to the product from magnetic permeability μ and field strength H of the magnetic field.
Implementation Method 3
A magnetic flux in accordance with the magnetic hysteresis curve (B-H-curve) having the same frequency as the excitation frequency of the alternating current is generated in the magnetic core. Due to the non-linearity of the permeability, an external magnetic field causes a distortion of the magnetic flux, which is detectable with the aid of the detection coil.
Data Source
AI summary
A system for detecting a magnetic flux includes: a magnetic-flux-generating coil having a first and second excitation-track elements extending essentially parallel to a reference plane; a flux-conducting structure for guiding the produced magnetic flux; and a flux-detecting coil having a first detection-track element for measuring at least a portion of the produced magnetic flux, the first detection-track element extending in a first plane defined by the first and second excitation-track elements between the first and the second excitation-track elements. The projection of the excitation-track elements of the flux-generating coil onto a projection plane extending parallel to the reference plane essentially covers the projection of the flux-conducting structure onto the projection plane, at least in the region of the windings of the flux-generating coil.