Giant Magneto-Impedance Sensor Impedance Compensation
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Solution Overview
Problem
Magnetic sensors face dynamic range saturation due to the earth's residual magnetic field, which overwhelms their ability to measure smaller magnetic fields, and existing solutions like geo-field nulling coils are bulky, costly, and limit miniaturization.
Innovation Solution
An impedance compensation method using a highly integrated impedance matching network with low-capacitance solid-state switches and a microcontroller to automatically null out the impedance change caused by the geo-field in Giant Magneto-Impedance fibers, allowing the sensor to maintain dynamic range for smaller field measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If geo-field nulling coils are used to compensate for the earth's residual magnetic field, then the sensor can null out the geo-field effect, but the device size increases and manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical/physical geo-field nulling coils with an electronic impedance matching network. The network uses solid-state switches, capacitors, and inductors to electrically compensate for the geo-field effect on the GMI fiber, eliminating the need for bulky magnetic coils while maintaining compensation capability.
Solution Approach 2:
The patent introduces an impedance matching network as an intermediary component between the GMI fiber and the measurement system. This network acts as a mediator that compensates for the geo-field induced impedance changes without requiring direct physical interaction with the magnetic field, thus avoiding the need for large nulling coils.
2Reliability
If geo-field nulling coils are used to compensate for the earth's residual magnetic field, then the sensor can null out the geo-field effect, but manufacturing cost increases
Solution Approach 1:
The patent replaces the expensive geo-field nulling coils with a cost-effective electronic impedance matching network consisting of standard solid-state switches, capacitors, and inductors. This substitution dramatically reduces manufacturing costs while maintaining the geo-field compensation functionality.
Solution Approach 2:
The patent uses inexpensive, readily available electronic components (solid-state switches, capacitors, inductors) to build the impedance matching network, replacing the costly and complex geo-field nulling coils. These electronic components are much cheaper and easier to manufacture than precision magnetic coils.
3Adaptability or versatility
If the sensor allows voltage to swing the entire range of the earth's geo-field, then the sensor covers the full geo-field range, but the dynamic range for measuring small magnetic fields is reduced
Solution Approach 1:
The patent converts the harmful effect of the geo-field induced impedance change into a beneficial compensation mechanism. The impedance matching network is configured to provide an equal and opposite impedance adjustment, effectively canceling the geo-field effect and freeing up dynamic range for measuring small magnetic fields.
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring the impedance matching network to counteract the known geo-field induced impedance changes before they affect the measurement. The network is designed to provide compensating impedance adjustments that preemptively offset the geo-field effects, ensuring optimal dynamic range for small field measurements.
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 eliminates the need for large geo-field nulling coils, enabling miniaturization and reducing manufacturing costs while preserving capture sensitivity, allowing for effective measurement of small magnetic field disturbances.
Implementation Method 1
If a soft magnetic conductor is driven by a high-frequency (typically radio frequency) current, and then undergoes an applied changing magnetic field, the resultant electrical impedance change of the conductor (which is often significant) is called the Giant Magneto-Impedance effect.
Data Source
AI summary
The invention is a method, described with the appropriate auxiliary electronic circuitry, for compensating the effect of the earth's magnetic field on Giant Magneto-Impedance magnetic sensors. The method as taught is an alternate way of cancelling out the effect of the very large residual earth's magnetic field using an impedance-tuning circuit (i.e. electrical compensation) rather than the usual magnetic type of compensation.