Current Divider Bridge for Flux Gate Sensor Bandwidth
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Solution Overview
Problem
Flux gate current sensors face challenges in measuring large currents due to limited demagnetization current capacity, which is constrained by the number of turns in the demagnetization winding and the resulting inductance, making it difficult to achieve high bandwidth and requiring large demagnetization voltages that are hard to achieve with standard components.
Innovation Solution
Incorporating a current divider bridge in the printed circuit of a flux gate current sensor, where accurately reproducible plated through holes form branches of the bridge, allowing for a known resistance ratio and reducing the current to be measured, thereby reducing the necessary demagnetization current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of turns of the demagnetization winding is increased to handle large currents, then the current measurement capability is improved, but the inductance increases which limits the rate of change of demagnetization current and reduces bandwidth
Solution Approach 1:
The patent divides the demagnetization winding into multiple separate windings (first demagnetization winding and second demagnetization winding). This segmentation allows the total number of turns to be distributed across multiple independent coils, reducing the inductance of each individual winding while maintaining the overall current handling capability. The segmented windings can operate in parallel, providing both the required current capacity and the necessary bandwidth for high-frequency operation.
2Reliability
If the demagnetization current is directly increased to compensate for large measured currents, then the current measurement range is extended, but a very large demagnetization voltage is required which is difficult to achieve with standard components
Solution Approach 1:
The patent introduces a current divider bridge as an intermediary device between the measured current and the demagnetization process. The bridge divides the large measured current into multiple smaller current paths, allowing the demagnetization windings to operate at reduced current levels. This intermediary structure enables the system to handle large current measurements while using manageable demagnetization voltages that can be generated by standard electronic components.
3Quantity of substance
If the inductance of the demagnetization winding is increased to improve current handling, then the current capacity is improved, but the rate of change of demagnetization current is limited which reduces bandwidth
Solution Approach 1:
The demagnetization winding is segmented into multiple parallel windings, each with reduced inductance compared to a single high-inductance winding. This segmentation maintains the total current capacity while reducing the overall inductance seen by the driving circuit. The parallel configuration allows faster current changes in each individual winding, thereby increasing the bandwidth of the flux gate current sensor.
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 accurate estimation of the main current by measuring a reduced current, thereby minimizing the demagnetization current required to compensate the magnetic flux, thus enhancing the sensor's bandwidth and operational efficiency.
Implementation Method 1
each first plated through hole and each second plated through hole connecting together the first track and the second track by extending through the insulating layer
Implementation Method 2
A flux gate current sensor makes use of the property of a magnetic material forming a magnetic core whereby it saturates from a certain level of magnetic excitation
Implementation Method 3
a square wave signal generator 2 applies a square wave excitation voltage Vex to the terminals of an excitation winding 3 wound around a magnetic core 4. The excitation current Iex flowing in the excitation winding 3
Implementation Method 4
a demagnetization current that flows in a demagnetization winding 8 and that serves to compensate the magnetic flux produced in the magnetic core 4 by the current Im that is to be measured
Data Source
AI summary
A printed circuit includes a first track, a second track, and at least one insulating layer extending between the first track and the second track. The printed circuit further includes a first through assembly of at least one first plated through hole and a second through assembly of at least one second plated through hole. Each first plated through hole and each second plated through hole connect together the first track and the second track by extending through the insulating layer. The first through assembly and the second through assembly respectively form a first branch and a second branch of a current divider bridge.