Soft Magnetic Core Noise Estimation Using Peak Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a lack of a clear and physically-interpretable analytical expression for estimating the noise of a soft magnetic core in fluxgate sensors, which hinders the optimization and performance stability of these sensors.
Innovation Solution
A method is provided to estimate the noise of a soft magnetic core by measuring impedance and resistance values of an excitation coil under different conditions, using high-order polynomials to fit inductance values, and calculating equivalent noise based on unsaturated inductance and resistance peak values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no analytical expression is formed for estimating soft magnetic core noise, then sensor optimization cannot be effectively performed, but this lack of expression makes it difficult to connect material research and development with sensor design
Solution Approach 1:
The patent transforms the noise estimation problem from a complex physical analysis into a parameter-based calculation system. By identifying key measurable parameters (impedance, inductance, resistance at peak frequency) and establishing their relationship with noise through empirical formulas, the patent enables systematic optimization without requiring complex theoretical models of magnetic domain dynamics.
Solution Approach 2:
The patent replaces the need for complex physical interpretation and theoretical modeling with a measurement-and-calculation approach. Instead of analyzing magnetic domain wall dynamics and Barkhausen noise mechanisms directly, the method uses electrical measurements (impedance spectroscopy, inductance, resistance) substituted for direct noise measurement, enabling practical optimization through standard electrical testing equipment.
2Measurement precision
If impedance measurement by frequency sweeping is performed to find peak frequency, then accurate noise estimation becomes possible, but this requires additional measurement steps and time
Solution Approach 1:
The patent performs frequency sweeping and identifies the peak frequency point in advance as a preliminary step. By determining the resonant or peak impedance frequency beforehand, subsequent noise estimation measurements can be focused at this specific frequency point rather than requiring continuous frequency scanning, thereby reducing the time for actual noise characterization while maintaining accuracy.
Solution Approach 2:
The impedance measurement by frequency sweeping serves multiple purposes: it identifies the peak frequency point, provides information about the magnetic core's resonant characteristics, and establishes the basis for subsequent noise calculations. This single measurement procedure fulfills multiple characterization needs, reducing overall measurement time compared to separate dedicated tests for each parameter.
3Ease of operation
If inductance and resistance values are measured under different direct current bias magnetic fields, then optimal excitation magnetic field can be determined, but this requires multiple measurements under varying conditions
Solution Approach 1:
The patent uses inductance and resistance measurements as intermediary parameters to determine the optimal excitation magnetic field. Instead of directly measuring or calculating the optimal field, the method uses these electrical parameters (which are easily measurable and respond predictably to bias field changes) as mediators. The bias field that produces maximum inductance or optimal resistance-inductance ratio is identified as the optimal excitation condition, simplifying the optimization process.
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
Enables accurate prediction and reduction of noise levels in fluxgate sensors, facilitating effective optimization and design by providing a clear estimation method for the soft magnetic core noise.
Implementation Method 1
measuring an impedance value of the excitation coil under a natural geomagnetic field by frequency sweeping
Implementation Method 2
exciting the soft magnetic core to a saturated magnetization state using the optimal excitation magnetic field
Implementation Method 3
measuring, under different direct current bias magnetic fields, an inductance value and a resistance value of the excitation coil at the peak frequency point
Data Source
AI summary
The present disclosure provides a method for estimating a noise of a soft magnetic core, including: acquiring a soft magnetic core, where an excitation coil is wound around the soft magnetic core; measuring an impedance value of the excitation coil under a natural geomagnetic field by frequency sweeping, and determining a peak frequency point when the impedance value reaches a peak; measuring, under different direct current bias magnetic fields, an inductance value and a resistance value of the excitation coil at the peak frequency point along an axial direction of the soft magnetic core to respectively obtain an unsaturated inductance value and a resistance peak value of the soft magnetic core; and obtaining an equivalent noise of the soft magnetic core based on the unsaturated inductance value and the resistance peak value.