Partially Compensated Coil Arrangement for Magnetic Induction Impedance Measurement
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Solution Overview
Problem
Magnetic induction impedance measurement apparatuses face challenges in accurately determining object parameters due to high signal noise ratios caused by the magnetic excitation field in detection coils, making it difficult to distinguish signal changes induced by the object's parameters.
Innovation Solution
A coil arrangement with a partially compensated magnetic excitation field in the detection coil, where the field strength of the net magnetic excitation field is within the magnitude range of the average field strength of the magnetic response field, enhancing sensitivity to signal changes and allowing for accurate parameter determination using the phase angle between the excitation and response fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the excitation coil is located in the vicinity of the detection coils to enable detection of the magnetic response field, then the measurement capability is improved, but the magnetic excitation field causes an additional current or voltage to be induced in the detection coils, leading to a poor signal-to-noise ratio
Solution Approach 1:
The harmful magnetic excitation field component is extracted and removed from the detection coil output through signal processing. The system separates the unwanted excitation field signal from the desired magnetic response field signal, eliminating the interference while preserving the measurement capability.
Solution Approach 2:
A reference signal from the excitation coil serves as an intermediary to enable cancellation of the magnetic excitation field interference. By using the known excitation signal as a reference, the system can subtract the harmful field component from the detection coil output through adaptive noise cancellation techniques.
2Measurement precision
If full compensation of the magnetic excitation field in the detection coil is implemented to improve signal-to-noise ratio, then measurement accuracy is improved, but the signal changes caused by object parameters become difficult to detect
Solution Approach 1:
Instead of fully compensating the magnetic excitation field, the system applies partial compensation by adjusting the compensation factor between 0 and 1. This partial action maintains enough excitation field presence to generate detectable signal changes from object parameters while sufficiently reducing interference to improve signal-to-noise ratio.
Solution Approach 2:
The system dynamically adjusts the compensation factor parameter to optimize the balance between noise reduction and signal preservation. By varying this parameter, the system can adapt to different measurement conditions and object types, changing the degree of excitation field compensation to maintain optimal detection sensitivity.
3Measurement precision
If the field strength of the magnetic excitation field in the detection coil is reduced to improve signal-to-noise ratio, then detection accuracy is improved, but the ability to induce eddy currents in the object is reduced
Solution Approach 1:
The system segments the magnetic field functions by using separate coils for excitation and detection. The excitation coil generates the magnetic excitation field at high power to induce strong eddy currents, while the detection coil operates at low power to detect the magnetic response field with high signal-to-noise ratio. This functional segmentation allows both high power induction and high precision detection simultaneously.
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 improves the accuracy of parameter determination by increasing the signal-to-noise ratio and enabling sensitive detection of small signal changes, facilitating easy and precise measurement of object parameters.
Implementation Method 1
a time-varying current is induced in the excitation coil such that the excitation coil generates the magnetic excitation field which penetrates through the object to be examined and accordingly induces the eddy currents within the object
Implementation Method 2
The magnetic response field is generated by the flow of the eddy currents in the object and is detected by the one or more detection coils in that a current or a voltage is induced in the one or more detection coils
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
A coil arrangement (215) for a magnetic induction impedance measurement apparatus comprises an excitation coil (208) configured for generating a magnetic excitation field in an object, and a detection coil (210-214) configured for detecting a magnetic response field generated in response to the magnetic excitation field inducing a current in the object (106). In order to enhance an accuracy of a determination of a parameter of an object, a value of a field strength of a net magnetic excitation field in the detection coil (210-214) comprises a magnitude range of an average value of a field strength of the magnetic response field in the detection coil (210-214).