Differential Signal Current Sensor With Offset Slots
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Solution Overview
Problem
Current sensors face challenges in providing consistent and accurate measurements in environments with stray magnetic fields and for electrical currents across a wide frequency range, as they are sensitive to unknown or undesirable magnetic fields.
Innovation Solution
A differential signal current sensor device with offset slots and integrated current sensors positioned within these slots to measure vertical magnetic flux, allowing for the cancellation of external magnetic fields and improved signal-to-noise ratio, eliminating the need for additional shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic current sensor is used to detect electrical current, then current measurement capability is provided, but the sensor becomes sensitive to stray magnetic fields causing incorrect measurements
Solution Approach 1:
The conductor is divided into multiple segments with slots created at different positions along its length. Multiple current sensors are placed in these slots to measure magnetic flux at different locations. This segmentation allows the system to distinguish between magnetic flux generated by the current (which appears at all slots) and stray magnetic fields (which may appear differently at each slot), thereby improving measurement accuracy in the presence of external interference.
Solution Approach 2:
Multiple current sensors are deployed at different slots along the conductor, creating redundant measurements of the same current-induced magnetic flux. By copying the sensing function at multiple locations, the system can compare measurements and identify/eliminate the effect of stray magnetic fields, ensuring accurate current measurement even when external magnetic interference is present.
2Object-affected harmful factors
If additional shielding and integrated magnetic concentrators are used to protect against stray magnetic fields, then resistance to external interference is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the magnetic flux measurement function from a single-point sensor and distributes it across multiple slots along the conductor. By taking out the sensing function and placing it at multiple locations, the system inherently gains immunity to stray magnetic fields without requiring additional shielding structures or magnetic concentrators, thus reducing device complexity while maintaining resistance to external interference.
Solution Approach 2:
The multi-slot sensor configuration enables the system to self-correct for stray magnetic field interference through differential measurement. The sensors themselves provide the means to identify and eliminate external interference by comparing measurements across slots, making the system self-protecting against magnetic interference without requiring external shielding components.
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 solution provides high accuracy and resistance to temperature increases and external stray field interference, reducing the requirement for integrated magnetic concentrators and additional shielding, thereby lowering costs and enhancing measurement reliability.
Implementation Method 1
One method for detecting and measuring an electrical current in an electrically conductive wire uses a Hall sensor based on the Hall effect. The Hall effect is the production of a voltage difference (the Hall voltage) across an electrically conductive material (such as a wire), transverse to an electric current in the material and to an applied magnetic field perpendicular to the current.
Data Source
AI summary
A differential signal current sensor device (100) may include a conductor (102) for conducting electrical current in a current direction. The conductor (102) may include a first slot (120A) extending from a first perimeter edge (122), towards a central axis extending along a length of the conductor (102), and a second slot (120B) extending from a second perimeter edge (124), towards the central axis. The current sensor device (100) may further include a first current sensor (130) positioned within the first slot (120A) and a second current sensor (132) positioned within the second slot (120B).