Dual-Core Current Sensor Layout for Wideband Accuracy
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Solution Overview
Problem
Current sensors with windings wound around the same core experience capacitive coupling issues at high frequencies, limiting their frequency band and affecting measurement accuracy.
Innovation Solution
A current sensor design featuring a first magnetic core surrounding the measurement-target object, a second magnetic core arranged next to the first, an excitation detection winding, an auxiliary winding, and a feedback winding wound around both cores to minimize capacitive coupling and enhance frequency band capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the feedback winding and auxiliary winding are wound around the same core, then the device complexity is reduced, but capacitive coupling occurs in high frequency band limiting the frequency band
Solution Approach 1:
The patent divides the single core structure into two separate magnetic cores (first magnetic core and second magnetic core). The feedback winding is wound around the first magnetic core while the auxiliary winding is wound around the second magnetic core. This segmentation physically separates the two windings, eliminating capacitive coupling between them and enabling the sensor to operate across a wider frequency band while maintaining structural simplicity.
2Volume of moving object
If windings are placed in close distance to reduce device size, then the volume is reduced, but capacitive coupling increases causing frequency band limitation
Solution Approach 1:
By segmenting the magnetic path into two separate cores with各自 windings, the patent achieves physical separation of the feedback winding and auxiliary winding. This eliminates capacitive coupling while maintaining a compact overall sensor structure, thus resolving the contradiction between small volume and wide frequency band operation.
Solution Approach 2:
The second magnetic core is positioned inside the first magnetic core, creating a nested configuration. The auxiliary winding on the inner core and feedback winding on the outer core are spatially separated yet maintain a compact overall structure. This nesting arrangement reduces sensor volume while preventing capacitive coupling between the windings.
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
The configuration allows for a wider frequency band and improved measurement accuracy by reducing capacitive coupling between windings, enabling more precise detection of measurement-target currents across a broader range of frequencies.
Implementation Method 1
a feedback winding wound around the first magnetic core and the second magnetic core, the feedback winding being configured such that a signal generated from the detection signal is input, the feedback winding being wound so as to cancel out magnetic flux of the first magnetic core
Implementation Method 2
an excitation detection winding wound around the second magnetic core, the excitation detection winding being configured such that an excitation signal for exciting the second magnetic core is input, and the excitation detection winding being configured to detect magnetic flux flowing through the second magnetic core and to output a detection signal indicating the measurement-target current
Implementation Method 3
an auxiliary winding wound around the second magnetic core, the auxiliary winding being configured to detect the magnetic flux flowing through the second magnetic core and to output an auxiliary signal indicating the measurement-target current
Implementation Method 4
a circuit configured to output an output signal indicating a level of the measurement-target current by modifying a signal output from the feedback winding based on a correction signal generated from the auxiliary signal
Data Source
AI summary
A current sensor includes an excitation detection winding configured such that an excitation signal for exciting a second magnetic core is input, the excitation detection winding detects magnetic flux flowing through the second magnetic core and outputs a detection signal indicating a measurement-target current. The current sensor includes an auxiliary winding that detects the magnetic flux and outputs an auxiliary signal indicating the measurement-target current. The current sensor includes a feedback winding wound around first and second magnetic cores, the feedback winding being configured such that a signal generated from the detection signal is input, and the feedback winding being wound to cancel out magnetic flux of the first and second magnetic cores. The current sensor includes a circuit to output an output signal indicating a level of the measurement-target current by modifying a signal output from the feedback winding based on a correction signal generated from the auxiliary signal.