Current Sensor Plate Magnetic Shields High-Frequency Detection
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Solution Overview
Problem
Current sensors face challenges in measuring high-frequency currents in wide plate-like conductors due to reduced detection sensitivity and increased measurement errors when adjacent conductors are close, leading to narrowed frequency bands and increased resistance losses.
Innovation Solution
A current sensor design featuring multiple plate-like conductors with magnetic shields positioned to minimize external magnetic field influence, allowing the magnetic sensor to be placed between the shields, which reduces measurement errors and widens the measurable frequency band without increasing sensor size or resistance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic sensor is placed near the center of the conductor in the width direction, then the detection sensitivity is improved for low-frequency currents, but the detection sensitivity is lowered at high frequencies due to skin effect
Solution Approach 1:
The patent transitions from a single-plane sensor placement to a three-dimensional arrangement by positioning the magnetic sensor between two plate-like magnetic shields that face each other with the conductor intervening. This spatial configuration allows the sensor to detect magnetic fields generated by high-frequency currents concentrated at the conductor edges while maintaining protection from external magnetic fields.
Solution Approach 2:
The magnetic shields act as intermediaries between the magnetic sensor and external magnetic fields from adjacent conductors. The shields block harmful external magnetic field interference while allowing the sensor to detect the magnetic field generated by the current in the target conductor, thus resolving the contradiction between sensitivity and frequency adaptability.
2Adaptability or versatility
If the magnetic sensor is moved to the edge of the plate-like conductor to improve high-frequency detection, then the frequency band is widened, but the magnetic sensor is easily influenced by external magnetic fields from adjacent conductors
Solution Approach 1:
The magnetic shields serve as intermediary elements that selectively filter magnetic fields. They block external magnetic fields from adjacent conductors while permitting the detection of the magnetic field generated by the current in the target conductor, thus enabling high-frequency measurement without exposure to external interference.
Solution Approach 2:
The magnetic shields provide localized magnetic field management around the sensor. The shields create a protected detection zone with different magnetic field characteristics than the surrounding environment, allowing the sensor to operate with high precision in a controlled magnetic environment while maintaining edge-positioning for high-frequency detection.
3Measurement precision
If the spacing between plate-like conductors is widened to reduce mutual magnetic field interference, then measurement error is reduced, but the size of the entire current sensor is enlarged
Solution Approach 1:
The magnetic shields act as intermediaries that actively block external magnetic fields, replacing the passive solution of increasing physical spacing. This allows maintain compact conductor spacing while achieving the same level of interference reduction that would otherwise require larger distances between conductors.
Solution Approach 2:
Instead of solving the interference problem by increasing horizontal spacing between conductors, the patent introduces a vertical dimension with magnetic shields positioned above and below the conductor. This three-dimensional shielding approach reduces mutual interference without increasing the horizontal footprint of the sensor.
4Measurement precision
If the width of the plate-like conductor is narrowed to widen spacing between conductors, then measurement error is reduced, but the cross-sectional area is reduced and resistance loss is increased
Solution Approach 1:
The magnetic shields serve as intermediary elements that actively reduce mutual magnetic field interference, allowing the conductor width to be maintained at optimal levels for both current carrying capacity and spacing. This eliminates the need to narrow conductor width solely for interference reduction purposes.
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 design effectively suppresses measurement errors caused by adjacent conductors and improves high-frequency detection sensitivity, enabling a broader frequency range while maintaining compact size and low resistance loss.
Implementation Method 1
two plate-like magnetic shields, each of which has a plate surface parallel to the virtual plane, the two magnetic shields facing each other with the conductor intervening therebetween
Implementation Method 2
a magnetic sensor positioned between the two magnetic shields. The two magnetic shields have the same length in a width direction parallel to the virtual plane and perpendicular to a length direction of the conductor
Implementation Method 3
At a high frequency, however, a current flows so as to concentrate near the edges of the conductor due to a skin effect
Data Source
AI summary
Each of three magnetic sensors is positioned on a first virtual line that passes the centers of two magnetic shields in the width direction and is perpendicular to a virtual plane, so a value detected by the magnetic sensor is less likely to be influenced by an external magnetic field. The first virtual line and the center of a conductor intersecting the first virtual line are separated from each other by a certain distance. Therefore, even if a distance from the center of the conductor in the width direction to the magnetic sensor is short, it is possible to improve, on a high-frequency side, frequency characteristics in the detection sensitivity of the magnetic sensor for the frequency of the current under measurement.